Raw materials

CHAPTER 1

Raw materials Stuart Howe Howe Brewing Consultancy, United Kingdom

Contents 1.1 Introduction 1.1.1. The importance and unimportance of ingredients 1.2 Malted carbohydrate sources 1.2.1. The Malting Process 1.2.2. Malt Specification 1.2.3. Production and Attributes of Special malts 1.2.4. Other significant malt types 1.2.5. Barley varieties 1.3 Unmalted carbohydrate sources 1.3.1. Why use them? 1.3.2. Pre-gelatinized cereal products 1.3.3. Grits 1.3.4. Oats - malted and otherwise 1.3.5. Sugars
syrups and dry 1.4 Water 1.4.1. The criticality of water 1.4.2. Water analyses 1.4.3. Salts, Ions and theories 1.4.4. Salts Calculations 1.4.5. pH, Alkalinity and Hardness 1.4.6. Additions and Adjustments 1.5 Hops 1.5.1. Background 1.5.2. The Bitter Stuff 1.5.3. The Aromatic Stuff 1.5.4. Polyphenolic materials 1.5.5. Hop Products 1.5.6. Varieties 1.6 Commercially Available Yeast and Bacteria 1.7 Recommendations for Procurement of Raw Materials Helpful Definitions

2 2 3 3 8 16 18 19 19 19 20 20 20 21 22 22 23 25 28 28 30 30 31 32 35 37 38 43 43 44 46

Abstract The raw materials you use, make the beer. Understanding what a “good” ingredient is, is a key skill of the successful brewer. The production and specification of malt, The Craft Brewing Handbook DOI: https://doi.org/10.1016/B978-0-08-102079-1.00001-1

Copyright © 2020 Elsevier Ltd. All rights reserved.

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adjuncts, yeast, water and hops are discussed and related to performance in the brewery and glass. How, where and why to buy certain raw materials is also described. This chapter is designed to acquaint you with some of the science behind your ingredients viewed through the lens of practical brewing experience. Hopefully after reading, you will be more confident in applying it to benefit your brewery and beer.

1.1 Introduction 1.1.1 The importance and unimportance of ingredients At one time it seemed every advert or package of beer featured the phrase brewed with the finest ingredients, some still do. That of course should go without saying and the marketing executive who coined the strapline ‘brewed with cheap malt and hop extract’ had a gloriously short career. Ingredients are also in the forefront of the mind of the consumer. Few would get excited about your wort separation system but most can identify with great malt or hops. Without wanting to undermine the importance of this chapter, the truth is, it is eminently possible to make good beer using low cost ingredients and even easier to make awful beer from the very best ingredients. When it comes to ingredients the success of the brewer depends on knowing the difference between good and bad (suitable and unsuitable) ingredients and then simply knowing how to get the best out of them. At this point I would like to introduce the truest phrase in brewing. Nothing is true until it happens in your brewery. You will read a great deal on internet forums or brewing guides from largely self-appointed experts about how certain malts give the best flavor for particular styles or how you can’t make a decent pilsner without a particular hop. Some of this I’m sure is true but there is also a lot of urban legend passed on by brewers and enthusiasts who want to appear knowledgeable without ever empirically demonstrating it. I was once in a German brewery discussing how to make an ESB (extra special bitter) with a group of young Russian brewers. They told me with burning conviction that you can’t make a decent ESB without using Maris Otter. This was news to the guy sitting next to me who happened to be a brewer from the brewery in London which makes the architype of the style and had never used Maris Otter to brew it! When reading information about ingredients look for the proper scientific evidence to back it up. Claims should be supported or supportable by work undertaken using scientific rigor and be published in a peer reviewed publication. Your online “global brewing expert” could

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be the bloke with the shakes who no one wants to sit next to from your local home brew club. If you want to know if something is true about an ingredient, ultimately you need to prove it in your brewery by doing identical side by side brews with and without it before analysing and evaluating the resultant brews, blind and without prejudice. Fact always trumps theory and opinion. As a brewer, the more you can understand the science behind the process, the easier it is to sniff out the urban legends and waste less time and money pursuing them. This chapter is designed to acquaint you with some of the science behind your ingredients viewed through the lens of practical brewing experience. Hopefully after reading, you will be more confident in applying it to benefit your brewery and beer and know brewing bullshit when you smell it.

1.2 Malted carbohydrate sources 1.2.1 The malting process The main malt used in breweries is barley so I will dedicate most of the discussion of malting to that of barley. Barley (Hordeum vulgare six row, Hordeum distichon 2 row) is a member of the grass family. The malted barley we use in beer is from a domesticated descendent of a wild grass which is abundant in northeast Africa and Western Asia. The grain we use is the seed of the grass plant. Two principal types are grown, one with six rows of seeds on the ear and one with two rows. Use of two row barley for malting and brewing is much more prevalent as it has a higher brewhouse yield and lower protein content. A cross section of a barley grain illustrating the key parts of its anatomy is shown in Fig. 1.1. Some beers are made with unmalted barley but this requires specialist equipment, the addition of enzymes and a greater degree of processing than that of malted barley. In short, the type of process which is only feasible in very large breweries. The malting process is divided into 3 stages, steeping, germination and kilning, although processing the barley on receipt is often as significant in terms of the time and effort taken to achieve it. The maltster is charged with the responsibility of taking a fairly flavorless, unfriable (difficult to breakdown during milling) seed in which any fermentable material is sealed in a matrix of proteins and gums and transforming it into an easily milled, readily converted grain with, for want of a better word, a malty aroma. During malting, the storage materials in the grain are unlocked by

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Figure 1.1 Anatomy of a barley grain.

the biological systems which the grain uses to grow into a barley plant. The grain is then dried to enable stability in storage and economy in transportation. Most craft brewers a start with malt as opposed to buying barley and malting it themselves, the economies of scale, capital investment required to set up a small maltings and concerns over quality/consistency of the final product make this proposition far from attractive. Fig. 1.2 shows the stages from barley to malt in a commercial maltings. (courtesy of Simpsons Malt). Steeping Water is critical to the germination process. Almost all of the reactions important for the freeing up of extract are hydrolysis (splitting with water) reactions. The steeping process involves providing the grain with the water and oxygen required to kickstart the growth of the seed. The barley delivered to the maltings will have less than 15% moisture. Through the steeping process this will typically increase to 42
44% for pale or pilsner malt and 44
47% for darker grains. There is some variation between varieties in terms of water requirement and effective management of the right conditions for germination is what the maltster is paid for! Steeping is the equivalent to a rain shower over the soil triggering the seed to start to grow. There are a range of steeping vessels in use in maltings but the basic principle of operation is the same. The grains are immersed in water to allow for the rapid uptake required for germination and the water is then drained off and an air rest is performed. During the air rest the CO2

Figure 1.2 The modern malting process.

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Figure 1.3 Rousing the steep.

produced by the respiring grain is driven off by aeration of the steep vessel. Air/rest steep time ratios vary from plant to plant but as a rule the more modern maltings tend to emphasize the air rest element. The critical aspect of steeping is that every grain experiences the same conditions and therefore is given the greatest opportunity to take up water and kick on with germination. Fig. 1.3 shows a steeping vessel being roused with air. This ensures even hydration of the grains and increases the oxygen level in the vessel. Germination The signal which switches on germination is the rise in hydration of the embryo to above 30% moisture. The architecture of the equipment used to undertake germination is even more diverse than that of steeping but all must achieve control of the elements of germination which impact on the quality of the malt. These are: 1. Water content of grain 2. Grain temperature 3. Availability of oxygen It is vital to ensure the moisture level in the grain does not drop or it will stop germinating. Germination produces a great deal of heat and this heat must be kept in check. Failure to do so will result in a loss of extract to excessive root growth and a reduction in the formation of enzymes which are required in the brewhouse to convert the mash. Without sufficient oxygen germination can cease and in extreme cases the grains become non-viable. To achieve the above, germination equipment

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features a means of applying moisture, aerating and ventilating the grains as well as a method of turning the grains. Malt suppliers are very friendly people and warmly welcome interested brewers. A visit to your local maltings provides an excellent overview of the mechanics and scale of the malting process and is well worthwhile. So that’s what goes on at a macro level, next we drill down to a micro level. During germination it is possible to roll grains between your finger and thumb and feel the extent to which the process has proceeded. Straight out of the steep, although moist the grain is hard and squeezing it will only succeed in bruising your thumb. Towards the end of germination as you rub, the grain will collapse and coat your thumb in barley paste. The processes which affect this change are termed ‘modification’. In response to the uptake of water the embryo sends a chemical message in the form of gibberellic acid to the aleurone layer which surrounds the endosperm. The gibberellic acid causes the aleurone layer to start manufacturing enzymes and β-amylase which is already resident in the endosperm is released from its complexes. The enzymes are the agents of degradation of the endosperm, catalysing the lysis of starch, gums, lipids and proteins. The seed at this stage is trying to grow so needs to mobilize the resources in the endosperm. To do this it must open up access to the energy store and remove the stored energy in the form of glucose. The glucose is stored as starch (amylose and amylopectin) in granules in the endosperm which are enclosed in cell walls. Enzymes from the aleurone layer work away at the β-glucans and proteins making up the cell walls rendering them porous. This allows the amylolytic (starch chopping) enzymes access to the starch granules. All this is great news to the brewer because we need the starch to give us our fermentable sugars and we definitely don’t need the large proteins or β-glucans because they will give us problems during wort separation and filtration. The trade-off of course is that when the seed starts to get hold of the starch, we are losing extract to the respiration and assembly of the growing plant. This is called the ‘malting loss’. There is a big, long list of enzymes, substrates and reactions which occur in malting which I don’t have the space to discuss and unless you are trying to baffle or impress you don’t strictly need to know. The key thing to understand is the basis of modification because this impacts on how the malt will perform in your Brewhouse and the specification which you will set the maltster for your favorite malt.

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Modification proceeds asymmetrically through the endosperm from the dorsal side of the embryo to the tip of the grain. Until the process has reached the tip some of the stuff you don’t want in your Brewhouse remains in the grain. While most of the malt specification relates to the sum changes during modification, several of the parameters cover the geographical extent of modification in your malt grains. Kilning The kilning stage is that part where the maltster stops the growth of the seed before it loses too much of its resources to growing into a new barley plant. It also locks in the enzymes and protects them from damage or decay during storage and transport. This is achieved by reducing the moisture content from above 40% to less than 5%. The removal of water is undertaken using heat and vast volumes of air flowing over the grain. Effective kilning is a balance of getting the most rapid termination of germination possible while causing the minimum possible damage to the viability of the malt enzymes and particularly in low color malt the avoidance of the formation of color and flavor by nonenzymatic browning. Non-enzymatic browning, also known as the Maillard reaction, involves a complex series of reactions between sugars and amino acids to form colored and flavored substances via intermediates. Not only are the products of non-enzymatic browning and their intermediates unwelcome in certain beer styles (no one wants to brew a nut brown helles) they are also precursors to stale off-notes in long shelf-life beers. At the start of kilning the temperature for low color malts needs to be kept low (sub 55 °C) to prevent the reactions above, to protect enzymes from being denatured and to prevent the production of steely grains where the starch of the green malt is gelatinized and then set into a nonfriable glass-like endosperm. When the moisture level is down below 10% the temperature can be raised to around 80 °C.

1.2.2 Malt specification Your malt specification should, if the malt supplier is up to the task, protect you from malt related headaches in the brewery. Poor malt will give you varying original gravities (varying volumes at collection and hence bitterness levels), extended processing times in the Brewhouse, inconsistent fermentations, filtration issues, hazes and off-flavors so the malt spec is very important. Figs. 1.4
1.6 show malt specs from UK, German and

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Figure 1.4 UK brewery malt specification.

US breweries. They are different in some terms, tests and unit of measurement but they all cover the same attributes of the grain. A malt spec should be achievable for the maltster and for base/white malt reviewed annually with the maltster to ensure both parties are happy with it and confident in it. If you are too small to ask the maltster directly to hit a spec you should review the analysis of their standard malts and reconcile them with what you want. The supplier who is closest can then be used to run a trial. Every malt spec should also have a statement covering food safety elements like non-approved pesticides, heavy metals, mycotoxins and N-Nitrosodimethylamine (NDMA) and a complete absence of GM materials depending on country and regulatory issues (NB the presence of GM materials is not a food safety issue per se).

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Paramater Variety Moisture Colour Boiled wort color Extract fine D.M. Fine/coarse grind extract difference Soluble protein Total protein Kolbach Friability Whole unmodified grains Wort viscosity pH NDMA content B –Glucans Diastatic power

Specification 2-row summer barley max 4.5% max 3.5 EBC max 6.5 EBC min 80% 1.0–2.5% 3.8–4.7% max 11.5% 35–45 min 80% max 3% max 1.60 cp max 6.1 max 2.5 ppb (**) max 250 ppm (*) min 230 WK (*)

: : : : : : : : : : : : : : : :

Specifications can vary depending on harvest quality (*) is not mentioned on the analysis report (**) controlled by HACCP-plan ; not mentioned on the analysis report Mycotoxins, pesticides and heavy metals controlled by HACCP-plan

Figure 1.5 A Belgian malt specification.

Specification Moisture content Extract fine grind, dry basis

Unit % %

Fine-coarse difference EBC

%

2.0

Viscosity (8.6%) Friability Glassiness

mPa·s % %

1.60 81.0

Protein, dry basis Soluble nitrogen Kolbach index

% mg/100 g Malz-Trs. %

9.0 610 36.0

Wort color

EBC

Wort color

L

Wort pH

Minimum

Maximum 4.9

80.5

2.5 11.5 750 43.0 2.9 1.5 5.7

Grading > 2.5 mm

%

90.0

Diastatic power

WK

250

6.1

Figure 1.6 A German malt specification.

Friability The friability of a grain relates to how completely it crushes. Poorly modified malt is less friable than its well modified counterpart. The material in a grain which doesn’t crush easily is likely to be the same stuff that will

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give you high wort viscosity, slow lautering/run off and filtration problems further down the line. As a minimum you should set 90% as a specification. Some schools of thought accept lower figures for Pilsner malt but most modern maltings can achieve above 90% on all malts. It is not sensible to condemn your brewery to processing issues unless you can personally demonstrate there is a tangible benefit in terms of flavor, stability or trueness to style from the poorly modified malt. Homogeneity Homogeneity takes friability a stage further by sieving the particles produced by the friabilimeter and weighing large pieces of endosperm. Any large pieces of endosperm will necessarily be unmodified or steely so specifications for homogeneity tend to have higher minimum levels, say 97
99% for a simple brewhouse. Total nitrogen (TN) This is the amount of nitrogenous material (protein, polypeptide, peptide and amino acids) in the malt and hence it is an indication of how much you will get in your worts. The nitrogenous material is derived from the protein in the barley used to make your malt, so higher nitrogen barleys give higher TNs. Yeast uses amino acids to build new cells during the growth phase of fermentation so providing sufficient soluble nitrogen is important for consistent and effective fermentations. If you are using high proportions of non-malt carbohydrate like maize, rice or sugar, selecting a malt with a higher TN is wise. A good proportion of the material which stabilizes foam is nitrogenous and nitrogenous material also contributes to palate fullness so ensuring you have a sufficiently high level in your malt is sensible. Sometimes protein is given instead of TN. You can estimate the protein level by multiplying TN by 6.25. One thing to bear in mind is that the as the amount of protein (nitrogen) in the grain increases the amount of starch and hence extract is reduced. There is therefore a practical upper limit. Kolbach index or soluble nitrogen ratio (SNR) The Kolbach Index is a measure of the degree of protein modification in the malt. The analysis determines the proportion of the malt’s nitrogenous material which dissolves in a standardized mashing process. The higher the number the greater the extent of breakdown of the barley proteins by the enzymes of germination. An index of below 35 suggests under

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The Craft Brewing Handbook

modification and an index of 41, over modification. The band in between indicates a malt with well modified protein. The SNR is as good an index of overall modification of the grain as friability or homogeneity. Free amino nitrogen (FAN) FAN is the weight per unit weight of amino nitrogen available from the malt. FAN is principally amino acids which as stated above are vital for yeast nutrition. While it might seem that having high FAN can only be a good thing if there is too much breakdown of the nitrogenous materials in the grain it is detrimental to the foam stability of the beer because the longer chained polypeptides and proteins which stabilize the bubbles in the head of beer are broken down into smaller molecules as FAN is produced. It is also thought that more extensively modified proteins in the grain detract from the body of the beer as some of the mouthfeel is conferred by polypeptides and proteins. The amount and degree of modification of protein in the malt is one of the many compromises in the process that you need to manage as a brewer. Diastatic power (DP) Diastatic power is the capacity of the grains to degrade starch during mashing and relates to the enzyme content of the grains. It is measured in the Institute of Brewing (IOB) analysis in degrees Lintner and in the European Brewing Convention (EBC) analysis in Windisch Kolbach units (°WK) the conversion is as follows Lintner 5 (°WK 1 16)/3.5 (NB other organizations, such as the American Society of Brewing Chemists, have their own methods of analysis so check what is best to use in your location) . It should be noted that however high the DP the malt will not have the capacity to degrade starch which is still encased in the gums or cells of an under/unmodified malt. A higher DP is important if you are using non-malt sources of starch like maize or rice as they provide no enzymes and hence require those from the malt to convert their starches to sugars. That is unless you are adding additional exogeneous enzymes. A DP of 35
45° Lintner should be sufficient for all malt brews while DPs around 120 would be necessary for above 20% non-malt material. Dimethyl sulfide precursor (DMS-P) Dimethyl sulfide (DMS) as you will discover later is the sweetcorn flavor evident in some lagers. DMS-P on a malt spec is the amount of the precursor to DMS in the grain. DMS-P will only be of concern in the paler

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white/base malt as it is destroyed by more intensive kilning regimes. Some maltsters also measure S-Methylmethionine which is also a precursor to DMS. β-glucan β-glucan in the malt specification refers to the concentration of β-glucan in a standardized wort produced from the malt and is measured in mg/L (sometimes referred to as parts per million or ppm). As indicated above, β-glucan is bad news in the brewhouse and filter room and indicative of under modified malt. If you have a very nice brewhouse which can have a β-glucan rest during mash conversion you can get away with a higher amount in the malt say a maximum 300 mg/L. If you have a simpler brewhouse or are averse to the risks posed by under modified malt a 120 mg/L as a maximum may be a better level. Moisture The percentage moisture of the grain is important. Too high and the grain will be at risk of mold and the enzymes are less well protected from decay. Mold on grain is a significant problem. The production of mycotoxins by molds can inhibit fermentation and contamination with Fusarium spp. can give rise to gushing in the finished beer through the production of heat stable polypeptides. There is also the small matter of their toxicity to humans! The obvious problem with high moisture is that you end up paying for a lot of water rather than grain. That said, it is very easy for the maltster to control so is very seldom a problem unless there have been problems in the supply chain. Extract Extract is the potential of the malt to provide principally, fermentable material (a small proportion of extract will be nitrogenous material, dextrins and trace elements). In a UK malt analyses the extract is given in liter degrees per kilogram Ld/kg of malt. So, for every Ld/kg in a malt the specific gravity of 1 L of water will be increased by one degree of specific gravity (SG) when the grain is mashed according to a standard procedure. The standard mashes for IOB and EBC are different. The IOB method is an analogue of the single temperature infusion mash and hence is isothermal whereas the EBC and American Society of Brewing Chemists (ASBC) methods more closely resembles the temperature programmed mash with progressively higher temperature rests. The EBC and ASBC

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Cane sugar Solution SG

Brewer's pounds

% W/V

divisor

SG 20C

Cane sugar

Balling

Baume

W/W

17.5C

modulus 145

1002.5

0.9 0.643

3.888

1.0025

0.641

1.0026

0.36

1005

1.8 1.287

3.885

1.0050

1.281

1.0051

0.72

1007.5

2.7 1.932

3.882

1.0075

1.9180

1.0077

1.08

1010

3.6 2.578

3.879

1.0100

2.5520

1.0102

1.43

1012.5

4.5 3.223

3.876

1.0125

3.1850

1.0127

1.78

1015

5.4 3.871

3.873

1.0150

3.8140

1.0153

2.14

1017.5

6.3 4.517

3.870

1.0175

4.4390

1.0178

2.48

1020

7.2 5.164

3.867

1.0199

5.0630

1.0203

2.83

1022.5

8.1 5.810

3.864

1.0224

5.6820

1.0227

3.17

1025

9 6.458

3.861

1.0249

6.3000

1.0252

3.52

1027.5

9.9 7.107

3.858

1.0274

6.9170

1.0278

3.86

1030

10.8 7.755

3.855

1.0299

7.5529

1.0303

4.20

1032.5

11.7 8.405

3.852

1.0324

8.1140

1.0328

4.54

1035

12.6 9.054

3.849

1.0349

8.7840

1.0353

4.88

1037.5 1040

13.5 9.703

3.846

1.0374

9.3520

1.0378

5.22

14.4 10.354

3.843

1.0399

9.9560

1.0402

5.55

1042.5

15.3 11.003

3.840

1.0423

10.5540

1.0427

5.88

1045

16.2 11.652

3.837

1.0448

11.1500

1.0452

6.21

1047.5

17.1 12.303

3.834

1.0473

11.7450

1.0477

6.54

1050

18 12.935

3.831

1.0498

12.3360

1.0502

6.87

1052.5

18.9 13.604

3.828

1.0523

12.9250

1.0527

7.20

1055

19.8 14.255

3.825

1.0548

13.5120

1.0552

7.52

1057.5

20.7 14.907

3.822

1.0573

14.0970

1.0576

7.84

1060

21.6 15.560

3.819

1.0598

14.6790

1.0601

8.16

1062.5

22.5 16.213

3.816

1.0622

15.2590

1.0625

8.48

1065

23.4 16.866

3.813

1.0647

15.8370

1.0650

8.80

1067.5

24.3 17.519

3.810

1.0672

16.4110

1.0675

9.12

1070

25.2 18.173

3.807

1.0697

16.9840

1.0700

9.44

1072.5

26.1 18.827

3.804

1.0722

17.5540

1.0724

9.75

1075

27 19.482

3.801

1.0747

18.1220

1.0749

10.06

1077.5

27.9 20.014

3.798

1.0772

18.6870

1.0774

10.37

1080

28.8 20.791

3.795

1.0797

19.2510

1.0799

10.69

1082.5

29.7 21.446

3.792

1.0821

19.8120

1.0824

11.00

1085

30.6 22.101

3.789

1.0846

20.3700

1.0849

11.30

1087.5

31.5 22.758

3.786

1.0871

20.9270

1.0874

11.61

1090

32.4 23.414

3.783

1.0896

21.4810

1.0899

11.91

Figure 1.7 Plato’s and balling’s table.

methods then require the use of tables that relate the strengths (sugar concentrations) of sucrose solutions with their specific gravities, the weight of extract in the laboratory wort is then calculated, assuming the material dissolved from the malt changes the specific gravity to the same extent as sucrose. What is extracted will not be sucrose but mostly maltose along with a host of other solutes. The EBC method uses Plato’s tables while the ASBC method uses Balling’s tables. Plato’s and Balling’s tables are shown in Fig. 1.7. The extract of the malt is expressed as a percentage.

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As a result of the differences in determination of IOB, EBC and ASBC extract there is no conversion factor between % extract and Ld/kg. That said, a rough conversion is made by multiplying % extract by 3.8. Low extract can be a sign of under or over modification, small corn size (lots of husk but little starch) and means you will need to use more grain to get the same original gravity (OG). Extract should really be as high as possible so only a minimum is set. Extract is specified either as is or on the basis of dry weight. It is possible to convert the dry weight to as is by multiplying it by (100 - %moisture)/100. pH The pH on a malt analysis is the pH of the wort produced using the standard mashing procedure. Lighter colored malts tend to have the highest pH and darker malts the lowest. The standard mashes are carried out using distilled water so there are no calcium salts to reduce pH. However, you should still take account of the malt pH when adjusting the water composition or calculating the volume of acid required for mash acidification. This is because variations in malt pH will have an impact on the pH in your mash, boil and finished beer. Color The color provided on a malt analysis is the color, measured by spectrophotometer or comparator, of the wort produced in the standard mash. Two mashes are used in the IOB method: 450 mL and 515 mL. Obviously the 450 mL figure will be higher as the wort is more concentrated. While the color measurement provided is helpful, it does not provide a precise measure of the color contribution of the malt to your beer because some color pick up occurs during wort boiling. The degree of this pick up is determined by the concentration of color precursors in the wort which will differ from malt to malt. Some analyses will give a boiled wort color but again this is only applicable to the mash and boil system employed in the laboratory at the maltings. The design and operation of your mash and kettle could give a significantly different color. European breweries and maltsters use °EBC as the unit of color measurement and US brewers and maltsters use SRM. SRM is roughly °EBC divided by 2. To calculate the theoretical color (excluding kettle color pick up) multiply the °EBC of the grain by the weight in kg, multiply the result by 10 and then multiply by the brewhouse efficiency.

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Divide the resultant figure by the volume produced in liters and you have your potential beer color. Steely corns Steely corns are poorly friable, will give little extract and may contribute materials which are problematic to run off and filtration. Specifying a limit for steely corns will prevent the maltster from blending over- and undermodified grains to hit specification. There should be less than 2% completely steely corns, preferably none! Steely corns are not friable so a low friability will coincide with high steely corn count. Whole unmodified corns are also given in some specs/analyses. It is sensible to view these in the same way as steely corns. As well as having a sound specification for your malt it is also important to undertake common sense checks on a representative sample at intake. The malt should be clean, free of mould or unpleasant smells, free of foreign bodies and broken grains (unless premilled!). It should also taste like delicious malt.

1.2.3 Production and attributes of special malts Special malt is the term used to describe malt which is used to contribute specific color or flavor attributes to beer. Malts used primarily for extract like pale ale and pilsner are termed white malts (UK) or base malts (US). All special malts are kilned to a higher temperature. In the production of cara and crystal the maltster manipulates the production process to favor the reactions between sugars and amino acids which give rise to sweet, rich, caramel-like compounds and precursors thereof. Below is a broad discussion of types of special malt. A number of maltsters now produce trademarked products which are variants of the basic types below and will be produced using techniques analogous to those detailed. It is wise to take with a healthy cynicism claims made about the properties of each product and what they will do to your beer, because they are all variations on a theme so are not likely to differ markedly to a competitor’s analogue. The information provided is primarily there to sell you the grain. Munich and Vienna Munich and Vienna malts are in effect darker versions of white (base) malts. It is argued by some that they are not actually special malts as their final processing is not carried out in a roasting drum. They contribute a greater amount of color and flavor but retain diastatic power. Their method of production encourages the formation of highly colored/

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flavored compounds through non-enzymatic browning. Munich comes in dark and light variants ranging from 15 to 35 EBC. Because of the way they are produced they have high potential for picking up color in the kettle by activation of color precursors. They are produced by germinating high nitrogen barleys until they are well modified but not overmodified and then kilning at elevated moisture levels and slightly higher kilning temperature. The result is a more richly aromatic grain than pale ale malt. Vienna malt is the lighter cousin of Munich made with well modified rather than highly modified barley and is kilned at a lower temperature.

Cara Cara is an abbreviation of caramel. This is a bit misleading because caramelization isn’t responsible for the flavor and color properties of any malt, let alone cara malt, although arguably they do have caramel-like properties. Cara malts are produced by allowing the endosperm of the malt to convert extensively to produce reducing sugars and amino acids and then kilning/roasting moist, at 150
180 °C to facilitate non-enzymatic browning. A range of cara malts are available from various suppliers which give different characteristics but all variations on the sweet, rich, malty and full-bodied theme. Because the endosperm has been heated at elevated moisture levels the enzymes of conversion are denatured and cara malts will not contribute any enzymatic power to the mash.

Crystal Crystal malts take the caramelization of the endosperm to the next level. The term crystal refers to the crystalline appearance of the endosperm of the malt. Crystal malts are produced from high nitrogen barleys which are then over-modified and roasted at very high moisture levels. The result is a stewing of the grain and extensive production of colored and flavored compounds through non-enzymatic browning. When the liquified endosperm is dried it sets into a glasslike (crystalline
hence the name) mass. As with cara malts, crystal malts range in color from golden to deep red. There is some crossover between high color cara malts and low color crystals. Crystal malt is thought to contribute to head retention and aid the action of finings. High percentages of crystal malts in grists (grain bills) can give rise to problems with sterile cartridge filters.

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The Craft Brewing Handbook

Black Black malts are prepared by roasting a standard malt to high temperature. The high degree of heating causing burning and burnt flavor. Dehusked malts are sold as less bitter and astringent than their standard counterparts. Although it sits comfortably within this style of grain, roasted barley isn’t actually a malt as the grains are not germinated before roasting.

1.2.4 Other significant malt types Acid malt Acid malt is a white (base) malt which has been sprayed with biologically prepared lactic acid or steeped in a sugar solution which is then converted into lactic acid by lactic acid bacteria, before kilning. The kilning increases the concentration of the acid to 2
4% volatile acidity. Acid malt is used as 5
10% by weight of the grist to reduce mash pH. Wheat malt Wheat malt is used at high rates in Weissbier and Witbier/Biere Blanche styles (50
60% in traditional wheat beers and anything up to 100% in modern “ground-breaking” ones) where it is said to confer characteristic softness and slight tartness. It is used by some brewers as a minor component in other styles to improve head retention and give a cleaner flavor. Wheat malt is huskless so has a higher extract potential than barley malt. Lack of a husk means it does not contribute to the filter bed during run off or lautering. This, the fact that it does not modify as completely as barley and has higher levels of the gums pentosans and glucans means that using high percentages in grists requires more elaborate equipment or a lot of patience. There are no dedicated brewing varieties as there are with barley but all wheat selected for malting for brewing is lower nitrogen than that used in food production because wheat proteins can give the same problems as the gums referred to above. Rye malt Rye has flat thin corns which often need to be milled on a different mill setting to barley malts. Like wheat it does not have a husk and has even greater pentosan levels so shares the same attributes during mashing. Rye has been said to give a smooth mouthfeel to beer, to give a reddish hue and confer a bready aroma.

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Alternative malted grains There are a number of other grains (cereals and so-called pseudocereals) which are malted in different parts of the world for use in beers that are often traditional in a particular geography. Many of these are being developed or used in more mainstream beers partly to explore new innovative cereals, partly due to potential cost savings and especially for production of gluten-free beers (pseudocereals not being grasses do not contain gluten). Several are difficult to malt and/or process in the brewhouse so anybody wishing to use these should investigate further. If you would like to know more a quick internet search will help but it is probably better to discuss with an expert or at least another brewer who has some experience in their use.

1.2.5 Barley varieties There are breeding programs in all the main barley growing areas of the world which develop new varieties through breeding and selection and unless you start brewing with a heritage variety like Maris Otter or Golden Promise the chances are after a few years the variety you buy will change. This is a good justification for using these premium price varieties. The impact of variety on flavor is however quite a contentious issue amongst brewers. As yet there is little scientific proof that valued/heritage varieties do confer superior flavor and even less showing they provide better brewhouse performance. Most experienced brewers would attest to the fact that the malting company making the malt certainly does have an impact on the quality of the flavor from the malt. One aspect which should not be forgotten in any discussion about the flavor from a particular variety, is that unless the grain processes consistently well in the brewhouse and provides the necessary nutrients to give effective fermentations any innate flavor quality in the grain becomes fairly insignificant.

1.3 Unmalted carbohydrate sources 1.3.1 Why use them? The use of alternatives to malted carbohydrate sources has been over time tainted with associations with low cost production of commoditized lagers. They are certainly cheaper than malt to purchase but in modern brewing their use is as much about what they can bring to the flavor,

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The Craft Brewing Handbook

foam or stability of a beer that drives the decision to use in all but the most monolithic scales.

1.3.2 Pre-gelatinized cereal products In order for starches to be hydrolyzed through the action of enzymes, the enzymes themselves need to be able to access the inner windings of the starch molecules. To enable this the starch must be moist and heated. Gelatinization is the name given to the disruption of the starch structure which gives this access. With malted barley gelatinization occurs at standard mash temperature in the mash tun or mash conversion vessel (MCV). For grains with higher temperatures of gelatinization the heat required must be provided by a cereal cooker or alternatively they can be bought in the pre-gelatinized form. Torrefaction is the process of heating a material to achieve a change in its composition. And micronization is just a posh way of saying making the particles of a material smaller. In micronized and torrefied cereals the starch is already gelatinized. Flaked products are also pre-gelatinized. Rice and maize both have gelatinization temperatures above that of barley so are pre-gelatinized before use in the mash tun or MCV. Both lack husk and have less protein than malt so do not contribute to filtration in the mash/lauter tun and tend to dilute FAN, TSN, foam potential and color. Both have less flavor potential than barley so are used to enhance the drinkability of beers. Both cereals are said to give a smoothness to beer palates. Maize is thought by some to give a corn-like aroma and taste to beer whereas rice just tends to dilute the flavor from the malt.

1.3.3 Grits Maize, rice and sorghum are also supplied as grits. Grits are small chunks of unprocessed endosperm. Rice grits are generally the by-product of processing of rice for food (the broken bits). Grits need to be cooked to gelatinize their starch granules before being added to a mash. Enzymes are also helpful to start the starch conversion in the cereal cooker or aid it in the mashing vessel. Grits have the same flavor/color properties as their torrefied counterparts i.e. not very many.

1.3.4 Oats - malted and otherwise Oats are supplied either malted, “toasted” or flaked/rolled. Some flaked oats arrive with husks whereas naked oats get their name from the absence

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21

of husk. The starch in oats will gelatinize at standard mash temperatures but flaked/rolled oats are pre-gelatinsed in any case. Oat corn size is substantially lower than barley so in 2- and some 4-roll mills they must be milled on a lower setting than the malted barley. Due to the high levels of β-glucans the amounts used must be kept low unless β-glucanase is to be added to the mash or a protracted β-glucan rest is employed. As well as high levels of gums, oats are also high in lipids. Lipids damage head retention and can lead to rancid off-notes in finished beers. Fashionable opinion has it that oats contribute a silky mouthfeel to beer there is however little scientific evidence that this is the case at present and some even describe them as providing a dry finish.

1.3.5 Sugars
syrups and dry Sugars are generally the most expensive source of extract. They are classified in terms of the number of sugar monomers linked together in the product or the dextrose equivalent (DE). The DE is the amount of reducing sugars present relative to D-glucose (dextrose). Sugars and syrups are prepared either from natural forms of sugar (cane and beet) or through the hydrolysis of starch by acids and/or enzymes. Glucose is the most refined form of sugar used in brewing. Some brewers feel that glucose gives beer a clean taste. Yeast will completely ferment a range of sugars to produce ethanol so it is unlikely that glucose produces a cleaner flavor than say maltose or sucrose. Glucose or syrups with sugar spectrums high in glucose should be used with caution because in its presence yeast represses (shuts off) the equipment in their cells for fermenting other sugars. If the percentage of glucose in wort is too high a slow or stuck fermentation (see Chapter 10) may result. This will certainly not make for a clean tasting beer! A range of syrups are available with different spectrums of sugars. Maltose is usually the predominant sugar in proprietary blends as it is the principle sugar in wort. Invert sugar was very popular in the last century. Invert sugar is sucrose which has been hydrolyzed into glucose and fructose by heat and an acid or occasionally with a hydrolytic enzyme. Different colors of invert are available and although the darker ones are more highly colored than plain sugar they do not contribute a significant amount of flavor or color when compared to even modestly colored malt. Below 70% solids, sugar syrups can support the growth of spoilage organisms so they are not supplied in a more dilute form. They are

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supplied and stored hot to prevent crystallization. The heat also makes it easier to pump the liquid to the point of use. Sugars are best used as late as possible in the brewhouse to avoid losses and color/flavor pick up. They are also used for priming in cask and bottle conditioning and for sweetness adjustment in filtered beers. When using sugars in recipes it is necessary to obtain the analyses from the suppliers which will detail the LdK/% extract of the sugar. For syrup colors you should not confuse the EBC/SRM given on the sugar analysis with that on a malt specification, the color displayed is the color of the syrup so will need to be adjusted by the dilution factor. For instance, adding 50 kg dark candy sugar with a color of 2000EBC to a 50hL brew the color contribution will be 20EBC. When added late in the boil or to hot wort in the whirlpool/hop back the brewhouse efficiency is close enough to 100% to not require a brewhouse efficiency adjustment factor in color or extract calculations.

1.4 Water 1.4.1 The criticality of water I’ll start by contradicting the title. The water you brew with is of no importance to your beer. What is important is the stuff dissolved in it. I must say in my experience we are a long way off understanding the impact of water on the palate of beer. Unlike aroma which we can quantify and qualify quite effectively using gas chromatography, beer palate remains a shadowy area of brewing. For this reason the impact of water on the palate remains slightly nebulous. Water chemistry isn’t the exciting part of brewing and other than breweries boasting about their crystal-clear mountain springs there is not a great deal of discussion about it at consumer level. I appreciate this sounds a bit dumb but as a general rule, if your beer tastes nice when brewed with your water then your water is good! As a faster test making tea with it can also be quite instructive. The water supply to your brewery is the least easy thing to obtain from an alternative supplier. The majority of small brewers will use the municipal supply because it is easier to connect to and potable. The cost of a borehole or abstraction from a local spring, would only pay back financially over a long period for most small breweries. Also, you have no guarantee that the water available from it will be suitable without the additional capital and operating cost of some form of water treatment. In Europe and the UK, water suppliers are required to comply with the EU

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23

drinking water directive (98/88/EC) which means it must be safe to drink. In the United States of America, municipal supplies are similarly covered by The Safe Drinking Water Act (SDWA). If you are looking for a site for a new brewery the right water supply as demonstrated by a trial brew and analyses over a few months is an essential requirement. Never forget that although they are required to ensure your supply is safe, municipal suppliers will happily supply you with water that makes terrible beer without telling you it has changed.

1.4.2 Water analyses If you use a municipal supply you can access a full suite of water analyses through the supplier who are required by law in many countries to make this information available to its customers. This analysis will however give you a range of data over which the water you get will vary throughout the year. If you are unfortunate enough to live in an area where diverse sources of water are used to supply one supply zone, your water may vary greatly from one day to the next. If this is the case use of reverse osmosis or ion exchange water treatment may be necessary to avoid your beer following the potentially wild inconsistency of your water. As well as the water supplier, the supplier of your water treatment salts (if used) may also offer water analysis and there are plenty of labs who will undertake the work although some of them charge an eyewatering fee and often use the water supplier’s labs as a subcontractor anyway. The water analysis provided by a UK water supply company is shown below in Fig. 1.8. Almost all municipal supplies are chlorinated which means the water will contain free chlorine. Free chlorine is not to be confused with chloride. Free chlorine is produced when chlorine gas is dissolved in water whereas chloride is produced when a salt containing chloride dissolves in water. If the supplies come from reservoirs (surface water) it is likely that the free chlorine will have reacted with organic materials in the water to produce undesirable flavor-active substances like trihalomethanes (THMs). Even if the free chlorine doesn’t react with organics in the supply water it can still react with the organic material in your brew to produce chlorine based off-notes. Free chlorine also attacks reverse osmosis membranes and sterile filter membranes. The antidote to all free chlorine related problems is adsorbtion on granular activated carbon in a carbon filter. Having chlorinated water doesn’t necessarily mean it is free of spoilage organisms so

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The Craft Brewing Handbook

Parameter

Legal limit

Units

Number of samples taken

Number of samples not meeting legal limit

Sample Results Min.

Average

Max.x.

Microbiological parameters Clostridium perfringens

0

No. per 100 mL

90

0

0

0

0

Coliform bacteria

0

No. per 100 mL

36

0

0

0

0

Colony counts (3 day at 22°C)

No abnormal change

No. per 1 mL

13

0

1

6

0

E. coli

0

No. per 100 mL

36

0

0

0

0

Enterococci

0

No. per 100 mL

2

0

0

0

0

1,2-dichloroethane

3

µg/L

6

<0.127

<0.127

<0.127

0

Alkalinity (as calcium carbonate)

No legal Limit

mg/L

1

176

176

176

0

Aluminium

200

µg/L

7

<14

<14

<14

0

Ammonium

0.5

mg/L

7

<0.042

<0.119

0.167

0

Antimony

5

µg/L

2

0.4

0.42

0.43

0

Chemical parameters

Arsenic

10

µg/L

2

0.36

0.39

0.41

0

Benzene

1

µg/L

6

<0.037

<0.037

<0.037

0 0

Benzo(a)pyrene

0.01

µg/L

2

<0.001

<0.001

<0.001

Boron

1

mg/L

6

0.081

0.097

0.123

0

Bromate

10

µg/L

6

<0.35

<0.94

1.56

0

Cadmium

5

µg/L

2

0.01

0.01

0.01

0

Calcium

No legal Limit

mg/L

1

114

114

114

0

Chloride

250

mg/L

6

77

79.7

83.2

0

Chlorine (free)

No legal Limit

mg/L

36

<0.05

<0.06

0.14

0

Chlorine (total)

No legal Limit

mg/L

36

0.25

0.57

0.92

0

Chromium

50

µg/L

2

<0.673

<0.673

<0.673

0

Colour

20

mg/L

Conductivity

2500

µS/cm @ 20 °C

Copper

2

Cyanide

50

Fluoride Hardness (total) as calcium

7

0.6

0.9

1.2

0

90

749

763

778

0

mg/L

2

0.014

0.017

0.019

0

µg/L

6

<1

<1

<1

0

1.5

mg/L

7

0.266

0.272

0.277

0

No legal Limit

mg/L

1

127.2

127.2

127.2

0

Iron

200

µg/L

13

<7

<9

12

0

Lead

10

µg/L

2

<0.16

<0.16

<0.16

0

Magnesium

No legal Limit

mg/L

1

8.33

8.33

8.33

0

Manganese

50

µg/L

7

<1

<1

<1

0

Mercury

1

µg/L

6

<0.029

<0.029

<0.029

0

Nickel

20

µg/L

2

3.17

3.29

3.4

0

Nitrate

50

mg/L

12

12.2

25

27.6

0

Nitrite

0.5

mg/L

21

<0.009

<0.048

0.191

0

12

0.307

0.516

0.569

0

13

0

4

47

1

0

Nitrite/Nitrate

1

Odour

Acceptable to consumers and no abnormal change

Dilution No.

PAHs (sum of 4)

0.1

µg/L

2

0

0

0

pH (Hydrogen ion)

6.5–9.5

pH value

7

7.56

7.68

7.8

0

Phosphorus

No legal Limit

µg/L

20

864

975

1040

0

Figure 1.8 A UK muncipal water analysis.

Raw materials

Parameter

Legal limit

Units

Number of samples taken

Number of samples not meeting legal limit

Sample Results Min.

Average

25

Max.x.

Potassium

No legal Limit

mg/L

1

10.1

10.1

10.1

0

Selenium

10

µg/L

2

<0.35

<0.35

<0.35

0

Sodium

200

mg/L

2

48.3

49.8

51.3

0

Solvents (tetrachloroethane and trichloroethene)

10

µg/L

6

0

0

0

0

Sulphate

250

mg/L

6

111

115

119

0

Taste

Acceptable to consumers and no abnormal change

Dilution No.

13

0

0

0

0

Temperature

No legal Limit

°C

36

6.2

8.7

11.6

0

Tetrachloromethane

3

µg/L

6

<0.094

<0.094

<0.094

0

Total organic carbon (TOC)

No abnormal change

mg/L

6

3.67

4.05

4.47

0

Trihalomethanes (THMs) (total)

100

µg/L

2

29.5

30.6

31.7

0

Turbidity

4

NTU

7

0.03

0.07

0.1

0

Pesticides Bentazone

0.1

µg/L

6

<0.004

<0.004

<0.004

0

Carbetamide

0.1

µg/L

6

0.009

0.014

0.029

0

Clopyralid

0.1

µg/L

6

0.021

0.03

0.044

0

Glyphosate

0.1

µg/L

6

<0.002

<0.003

0.005

0

Metaldehyde

0.1

µg/L

6

0.073

0.081

0.09

0

Metazachlor

0.1

µg/L

6

<0.003

<0.003

<0.003

0

Pesticides –Total

0.5

µg/L

6

0.148

0.167

0.187

0

Propyzamide

0.1

µg/L

6

0.02

0.024

0.026

0

Quinmerac

0.1

µg/L

6

0.015

0.017

0.018

0

Figure 1.8 (Continued)

mains water should not be used alone as a final rinse medium for cleaning-in-place (CIP) without further disinfection/sanitization. It is also wise to note that without the protection of free chlorine, any water which isn’t stored hot after the carbon filter will quickly resemble a stagnant pond due to the growth of microorganisms.

1.4.3 Salts, ions and theories There are broadly two schools of thought when it comes to salts. UK brewers tend to think that adding principally calcium salts to achieve a spectrum of ions in the water and hence beer is the best way to control water, mash, wort and beer pH and affect the palate of the beer. European brewers tend to control mash pH through acidification either through acidulated malt or biological/mineral acidification. There is some evidence that certain ions give particular palates to beer. However much of prevailing theory about chloride and sulfate etc. seems to be based entirely on work done in a single lab in Manchester, England in the 1970s.

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The best way to understand this in your own brewery is to conduct brews of the same beer with varying profiles and see which profile gives you the palate you are after. When evaluating the beers make sure you follow correct sensory protocols (blind difference tests with sufficient assessors and proper data handling) which remove the effect of expectation. As follows are some of the ions which are implicated in affecting beer palate: Sulfate SO22 4 Sulfate is generally held as the dryness ion. In the UK, sulfate is the ion favoured in ales whereas chloride is favoured in lagers. It is thought to enhance hop bitterness and provide a dryer finish. Some believe sulfate acts in tandem with chloride and the dryness/sweetness balance of the beer is affected by the ratio of the two ions. Sulfate is generally added to the brew in the form of calcium sulfate (gypsum) or by adding sulfuric acid to water with excess alkalinity. The water of Burton-upon-Trent in the UK is very high in calcium sulfate, so high in fact that the mega breweries use reverse osmosis (RO) to strip it out of all water used for brewing. Calcium ca21 Calcium is necessary in brewing water. Calcium interacts with phosphate and phytate in the mash which reduces mash pH. Calcium enables the effective operation of α-amylase in the mash and is used by yeast during flocculation. It is also important to have sufficient calcium available to deposit out calcium oxalate which causes a scale-like beer stone on fermentation vessels and when left in packaged beer can cause gushing through bubble nucleation. In extremely high concentrations it causes hazes in beer. Too much calcium in the water leads to excessive precipitation of phosphate which the yeast requires during growth and fermentation. For this reason it is sensible to have levels of calcium of less than 100 ppm in brewing water. Some brewers add a great deal more than this to control pH and to add the sulfate and chloride they feel are essential to the palate of their beer. Calcium itself is not currently thought to have any impact on palate but all of the anions associated with it are. Magnesium Mg21 Magnesium acts in a similar way to calcium in reducing pH but its effect is not so marked. It is required by yeast as a nutrient during growth and

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27

fermentation but only at around trace levels. Magnesium is not thought to have an impact on palate until at above 30 ppm when it gives a sour bitterness. Sodium Na1 Sodium is said to give a full sweetness to beer when present between 50
120 ppm. Above this level it gives a similar sourness to magnesium. Sodium is not commonly above 10 ppm in water supplies so to get the levels detailed above the addition of table salt (sodium chloride) is required. Chloride Cl2 Chloride is thought to be the ion of fullness/sweetness and roundedness. High levels of chloride can give beer a salty or pasty texture and detract from drinkability. As mentioned above the ratio between chloride and sulfate is thought to be important with regard to regulating the palatability of the beer. It should be noted that malt can be a rich source of chloride so you need to take account of this when deciding on the amount to specify in your water. Chloride, like sulfate is generally added in form of its calcium salt and sometimes through the removal of excess alkalinity by hydrochloric acid. Iron Fe21 Any level of iron above trace level in water supplies is bad news. Iron ions are very flavor active giving a bloody/metallic off note to beer. Iron also forms slimes in pipework and is toxic to yeast. Iron like the other transition metals, copper and manganese, is also involved in oxidative spoilage acting as a catalyst to oxidation. Breweries fed by municipal supplies can suffer from isolated incidences of iron contamination as old mild steel supply mains are disturbed. This will be delivered to the brewery as suspended sludge so some form of back washable physical filtration on the incoming main would be adequate to stop the issue before it arrives at the brewery. Iron in a water supply is relatively easy to remove through oxidation and sedimentation. Nitrate NO3Nitrate is often found in surface water contaminated with nitrates from industry or agriculture. Nitrate can be chemically reduced to the carcinogenic nitrite by bacteria so should be minimized in brewing water.

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High levels of nitrate can cause rapid fermentations due to a higher level of nitrogen available to yeast. Municipal supplies must have a nitrate level below 50 ppm by law in the UK so levels are not a concern for brewing but this may vary in other countries. Breweries fed by shallow springs or surface water are likely to need to treat the water to remove nitrate. Nitrate can be removed by ion exchange or reverse osmosis.

1.4.4 Salts calculations Salts dissolve and disassociate to give ions. For example, sodium chloride (NaCl) will give Na1 and Cl2 in water. The proportion of the weight of the salt contributed by the component ion is equal to its contribution to the salt’s molecular mass of the ion. For example, 1000 g of sodium chloride (NaCl) which has molecular mass of 58.44 g/mol is made up of chloride with an atomic mass of 23 g/mol and sodium with an atomic mass of 35.44 g/mol will have Chloride 5

1000 1000 3 23 and sodium 5 3 35:44 58:44 58:44

or 393.6 g of sodium and 606.4 g of chloride. So, if you dissolve 1 kg of NaCl in 100hL of water you have 39.36 mg/L (or ppm) of sodium ions and 60.64 mg/L (or ppm) of chloride ions. To calculate the molecular mass for salts where there are two anions like calcium chloride (CaCl2) you need to multiply the atomic mass of the anions by 2. When aiming for a particular ionic profile in beer you must of course factor in the contribution of the ions already in the water and for a final beer profile the contribution of the malt, yeast and process.

1.4.5 pH, alkalinity and hardness The correct pH is critical to most of the reactions during beer production. As both the principal component and the medium for these reactions, controlling pH of the water is therefore essential. pH is affected by materials in solution in the water. The relationship between pH and alkalinity is the stuff of headaches. Alkalinity is the ability of water to neutralize acids whereas pH is a measure of how acidic or basic (alkaline) the water is. Confused? It is quite possible for water with high alkalinity to have a pH of less than 8. Alkalinity is conferred by carbonate, bicarbonate and hydroxide all of which are basic chemicals and are pretty unwelcome in the brewery. Although some hardness ions confer alkalinity, alkalinity is not hardness. Hardness is a general term for the mineral content of the

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29

water and hence the ability of the water to absorb soap. Hardness is termed temporary or permanent. Temporary hardness decomposes and then precipitates when heated whereas permanent hardness does not. Temporary (calcium and magnesium bicarbonate) hardness is unwelcome because it raises water pH and scales up the hot liquor tank in the brewhouse. Some permanent (calcium sulfate) hardness is very welcome and often added deliberately. Lower pHs at every stage of brewing favor better processing and superior palate. I say low pH but perhaps absence of higher pH is a better way to put it so you are not tempted to add IBCs of mineral acid to every brew. Lower pH in the mash gives a better conversion of starch and proteins to fermentable material and FAN, in boiling while it does reduce hop utilization a lower pH favors a more effective removal of haze forming substances, lower color pick-up and it is believed the production of a less astringent (drying mouthfeel) palate. A lower pH in the finished beer helps yeast flocculation, makes finings work more effectively in the cask or tank, gives an improved shelf-life and cleaner palate. Low water alkalinity and the correct concentration of calcium in the brewing water are instrumental in giving these lower pH conditions. The EBC recommend an alkalinity of 20 mg/L (or ppm) for Pilsners. 50 ppm maximum has been mooted as the maximum for ales and 100 ppm for stouts and porters. Theory has it that darker beers should be brewed with more highly alkaline water. Colored malt is more acidic than white malt and tends to reduce more alkalinity by neutralisation in the mash. Prevailing pHs through the process will therefore not be that much higher than a light-colored wort made with brewing water with a lower alkalinity. Simple testing equipment for alkalinity and hardness is inexpensive and easy to use and if you have varying supply characteristics monitoring both and adjusting your treatment regime accordingly is essential. Also reconciling the changes with any fluctuations in beer palate is worthwhile to determine the best supply characteristics for your beers. If you don’t measure it, you can’t manage it. It is worth investing in capable pH measuring equipment with at least a 2-point calibration. It is also worth reading the instructions and following them to the letter. Most importantly it is essential to keep the pH meter safe in a dedicated room (dare I say lab) where its use can be monitored. pH electrodes are very costly and very fragile. Cheap handheld pH

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The Craft Brewing Handbook

meters are very inaccurate so should be avoided. The money saved buying one will be spent on throwing bad beer away.

1.4.6 Additions and adjustments There are a range of commercially available water additives/adjustments ranging from food grade chemicals to proprietary treatments. The producers of the treatments often offer free analysis of brewery water and recommendation of addition regimes. When trialing an adjustment regime you must have the beer analysed to confirm that the desired ionic profile has been achieved. Yeast, malt and the effects of the brewing process can change it markedly from what was there at the start. When adding chloride to water you must be careful not to allow chloride levels above 15 ppm in water stored above 50 °C. Above these levels all but the very highest grades of stainless will suffer stress corrosion. Several breweries have learned this the hard way with hot liquor tanks converted to tea bags over a few months. Some mill manufacturers take a dim view of adding calcium chloride with the grains prior to the mill as it is hygroscopic and causes corrosion in ferrous components. Gypsum is not especially soluble in water or wort. Care must be taken when adding it to mashing systems without mixers as it can just settle out on the base of the vessel to form a sludge under the false floor. Adding acids to adjust alkalinity should be undertaken with care from a health and safety perspective and you must also check alkalinity and pH before and after addition if you have varying water supply characteristics. Lactic and phosphoric acid are generally safer than sulfuric acid and hydrochloric acid. Hydrochloric acid’s propensity to fume means it is not usually employed on its own above single figure concentrations. Lactic acid is available as a concentrated liquid (80%) and also in the form of sour wort which means you don’t need to install a biological acidification plant to reduce alkalinity the reinheitsgebot-friendly way. It is however a very expensive way of getting the job done.

1.5 Hops Hops are the rock stars of the raw materials. More experienced brewers can remember a time when they all smelt like hops and aroma hops were those with low alpha acid levels. The last decade has seen all that change with a plethora of exciting new varieties created by breeding programs which seemed to have escalated to a kind of arms race of aroma and

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bitterness with a few people making a fortune in the process. Fig. 1.9 shows hop cones on the bine nearly ready for harvest in Australia.

1.5.1 Background For centuries brewers used spices and herbs (gruit) to make the beer of the day taste less awful and go rancid slightly less rapidly. Over the years other constituents of gruit fell out of favor and the hop became the norm in beer. It is thought that the bacteriostatic properties of hop derived compounds were the most significant aspect driving this change. The hop as termed in brewing are the stobilus (cone) of the hop plant (Humulus lupulus). The hop plant is a perennial which means it lives for more than 2 years. In fact, hop plants take around 2 years to produce a

Figure 1.9 Topaz hops.

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good yield. The hop plant dies back in the autumn leaving only the rootstock. In the spring the shoots appear and the plant again climbs as it grows. In nature the plant grows using vegetation like hedges to grow over whereas in the hop yard/garden it is manipulated to grow up wires or strings. The plant is dioecious, having either female or male reproductive equipment on each individual plant. Only the females are grown for hop cone production and male plants are excluded from the area to prevent pollination giving rise to unwelcome hop seeds. Hops will grow in most temperate regions of the world but cultivation tends to be undertaken in areas offering the climate to give a good yield and provide the right conditions for harvest and storage. Almost all commercial hop cultivation is between 30 and 50° North and 30
50° South of the equator. The stobilus consists of a central axis otherwise known as strig or spindle which is connected to the stalk and has a zigzag pattern. To the strig are attached the stipular bracts which are small leaves and bracteoles or bractlets which are even smaller but have the all-important lupulin glands attached. The lupulin glands contain the brewing principles, the resins (the bitter or potentially bitter stuff) and the essential oils (the aromatic stuff). The structure of the hop cone in dissection is shown in Fig. 1.10.

1.5.2 The bitter stuff The hop resins are divided in two and called the hard and soft resins. The soft resin is made up of the α-acids and β-acids. The hard is composed of compounds which may contribute some bitterness but not an especially large amount. β-acids are secreted first during the development of the strobilus, and consist mainly of lupulone, colupulone and adlupulone and are a great deal less bitter than the α-acids and there is some conjecture about the impact of their oxidation products on beer palate. The unoxidized β-acids are only very sparingly soluble in water and beer so it is unlikely that they will have a major impact on hop derived character. The oxidation products are more soluble and can contribute around a 30% bitterness yield when compared to iso-alpha acids. As the formation of the oxidation products requires time and poor storage conditions, unless you are in the habit of using tired hop cones, β-acid oxidation products should not be a problem for your beer. Hulupones are formed when β-acids oxidize and are 4 times more bitter than α-acids. Hulupones can be formed during wort boiling although in standard wort boiling not much more than a few parts per billion (ppb) appear to be

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Figure 1.10 The cross section of a hop cone. Courtesy of Barth Haas.

produced because oxygen is naturally driven off during the boil. Some oxidation products of β-acids have been characterized as having long lasting bitterness and have been found in commercial beers but not above the sensory recognition threshold of the compound. It seems reasonably safe to conclude from all the work on β-acids that although the oxidation products are not things of beauty, they are not around in sufficient amounts to cause a significant problem to beer palate. If your beer tastes awful don’t spend time looking up the β-acid level in your hops unless you have looked at more likely sources of awfulness first. The alpha acids are humulone, cohumulone and adhumulone and are all based on a standard carbon skeleton with slightly different side chains. Cohumulone is the alpha acid with all the bad press. It was thought to have a harsher bitterness and to have a negative impact on head retention. For this reason you will see % cohumulone as part of a hop analysis. Recently doubt has been cast over the widely-held antipathy for this alpha acid. A study using almost pure cohumulone as a source of isobitterness showed that the quality of the bitterness was as pleasant as that of its humulone and adhumulone analogues. Traditional nomenclature tended to class lower alpha acid hops as aroma hops and included in these are the noble hops. With the strides made through modern breeding programs in the creation of varieties with

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both very high alpha and bold, striking aromas, the term aroma hop doesn’t fit the lower alpha hops quite so well. There seems to be two main schools of thought when it comes to the quality of bitterness. In one camp are the brewers who prefer to use a lot of low alpha/noble hops, like Saaz or Mittelfrüh using them in first worts to maximize the time the hops spend in hot wort. In the other are those who favor super high alpha varieties, like Summit or Magnum added sparingly the start of the boil. A lot of brewers have a favorite hop to use for bitterness. Some evidence to support the low alpha hop camp was offered by a Hopsteiner study where a flavor panel found beers bittered with low bitterness “aroma” varieties to have a rounder/softer bitterness than their bittering hop counterparts. Proponents of the high alpha hop method would point to the greater extraction of polyphenolic materials from the larger volume of intensively boiled first wort hops as a source of astringency and hence negative influence on the overall palate. Quite a few respected brewers sit in either camp so as with malt varieties you are best off experimenting with your own beer with the bittering hop addition as the only change and seeing which variant you and your flavor panel/focus group prefer. Any discussion about the olfactory quality of bitterness should take account of the other factors of beer production/ composition which may turn the sensation caused by substances which could give a rounded bitterness into an aggressive lingering one. The variety of hops and the way they are used are only part of the story. The iso-apha acids are thought to be the most significant element of the hop to the bitterness of beer and because of this the bitterness of beer is often synonymous with the IBU/EBU (International Bitterness Unit/ European Bitterness Unit shortened to BU in this chapter to avoid an international incident). Alpha acids in the hop are not very soluble in wort/beer but are converted to iso-alpha acids in the boil by isomerisation. Iso-alpha acids are more soluble but not overly so. They are surface active so tend to stick to material that beer touches. This is why you lose BUs on filtration and why the bitter sensation of beer tends to linger on the palate. The BU is not per se a measurement of the sensory bitterness of beer but is the concentration in mg/litre of iso-alpha acids which are derived from the alpha acids from the hops when the hops are boiled or isomerized by heating. While BUs may be indicative of the bitterness of a beer they have no direct relationship with the flavor and aroma of hops in the beer. It is quite possible to have beer with 100BU which has no hop aroma and have a beer which smells like a stroll through the hop bines

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with less than 10BU. Another misnomer is that hops have BUs. Hops have a % by weight alpha acid content which indicates bittering potential but is not in itself a BU. The relationship between the amount of alpha added in the form of hops or hop products and the concentration of iso-alpha acid in the beer is called the hop utilization it is represented by the following equation. Hop utilization 5

concentration of iso-alpha acid in beer ðmg=LÞ 3 100 amount of alpha acid added to brew ðmg=LÞ

Is it affected by type of hops used, when they are added, the pH of the boil, the vigor of the boil, degree of trub removal, the length of the boil, the degree of downstream processing, pitching rate, dry hopping etc. Measurement of bitterness at various stages of the boil will give utilizations for hops added at those times. Thus, the amount of BUs derived from each addition can be estimated in the recipe for a new product. All brewhouses and production systems will be different in that regard. You will also find variations between recipes boiled in the same way as pH, wort gravity and prior hop additions will all affect hop utilization. Recently another source of bitterness, this time contributed by dry hopping has been identified. Humulinones which are found in hops and are the result of peroxidation of α-acids are soluble in beer and are 0.66 times as bitter as iso-alpha acids. On a molecular level they look fairly similar to isoα-acids.

1.5.3 The aromatic stuff The essential oils of hops are volatile. That means they evaporate easily and fly up your nose. It also means they are lost easily when the wort is boiled. They are the part of the hop which the world of brewing and brewing science love to talk about. This is mainly due to the fact that with analytical techniques such as Gas Chromatography (GC) it is a great deal easier to measure their concentration and the compounds which constitute them are ubiquitous in nice smelling things in nature so it’s easy to draw comparative descriptions. One thing I would like to make very clear is that other than a slight influence they don’t affect how beer feels in the mouth or how it finishes on the palate. Essential oils are very complex chemically and are made up of hundreds of compounds. Rather like designer perfumes, hop aroma is a blend of organic chemicals. Although hundreds of chemicals are found in hop

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aroma from the hop cone or the rub of hop on your hand a great deal fewer remain in the hoppy aroma in beer. The components of essential oils are generally divided into 3 groups, namely, hydrocarbons (compounds made of carbon and hydrogen) oxygen containing compounds (as above but with some oxygen) and sulfur containing compounds. The hydrocarbons are the most plentiful of the groups but are also the most volatile so less likely to be found in beer at detectable levels. It is thought that most of the “hoppy” aroma is contributed by the oxygen containing fraction which is complex and diverse. The smallest proportion of the essential oils is the sulfur containing fraction but these compounds have the lowest aroma thresholds (i.e. small amounts can be detected on the nose). The component compounds of the essential oils may combine to produce the aroma, the presence of one compound may boost the contribution of others or supress it. If you add to this relative volatilities of the components and the changes wrought in the brewing and fermentation process, you have a very long way to go from the stuff you smell in a hop garden to the aroma wafting forth from the glass as you drink. So, while the descriptors given in hop data sheets or on-line are helpful they will not accurately predict the impact that hop has on your beer. We are a long way from agreeing what hoppiness is and even further from pinpointing the source of hoppiness. The dynamic nature of hop aroma and the concept of a hoppy beer makes the challenge even harder. As follows is a discussion of some of the essential oil components often referred to in hop analyses. Linalool Linalool is a floral and spicy terpene alcohol. It is found in over 200 plants such as citrus fruits and lavender. Concentrations of linalool above 20 ppb have been shown to give a fruity hoppy aroma to beer. Linalool concentration has been described as an indicator of hoppy flavor and it has been suggested that aiming for a linalool concentration rather than BUs gives better results when looking to make a “hoppy” beer. While this is a nice idea it would require using a GC to measure linalool concentrations in your beer and hence calculate the linalool utilization of your process. This is not really within the means of a brewery which is not pretty sizable. Higher levels of linalool have also been shown to reduce the threshold concentrations of off-notes like diacetyl. Linalool exists in two chiral forms, R- and S-linalool, the R form is a great deal more flavor active.

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Myrcene Myrcene is a hydrocarbon and one of the key components of hop aroma. In Brewer’s Gold hops, it was found that it contributed 58% of the odor units and was also found to be the most significant element of the Spalter Select hop fragrance. Myrcene has been described variously as has having a resinous/green/citrus/pine aroma and is found at higher concentrations in new world hops. Geraniol Geraniol is an alcohol that gets its name from the geranium plant. It is also found in rose essential oils. It is therefore unsurprising that it has a floral fragrance. Slightly more surprising is that it is a key component of fruit aromas such as peach and raspberry. Farnesene It is thought that the aroma of the noble hops is to a degree characterized by higher levels of farnesene. It was first identified in Saaz hops. It has a herbal/woody/floral aroma but is very volatile therefore is not generally found in beer so it is more an indicator of the potential of the hop than of importance to the character of the beer produced. Humulene Humulene, also known as caryophyllene, is an isomer of β-caryophyllene and exists in a mixture of the two isomers in hops. Higher levels of humulene tend to be found in noble hops compared to other varieties so while farnesene levels indicate noble hop like characteristics, humulene levels seem also to be in part responsible. Higher levels of humulene in noble hops should not automatically be taken to mean that it is responsible for the noble hop note in beer. By the same token high myrcene is not solely the reason new world hop based beers smell the way they do. The hop nose/taste of beer is very complex both in composition and production so it is unlikely that one convenient compound will be responsible for a characteristic nose. And anyone saying, “I’m getting a strong myrcene note on this beer” isn’t!

1.5.4 Polyphenolic materials As well as the bittering of the resin components and aroma of the essential oils hops also contribute polyphenols (tannins) to beer from the structural material of the cone. On the positive side polyphenols contribute to

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palate fullness in beer and have antioxidant properties but on the negative side they can taste astringent and form hazes by reacting with proteins. While the total amount of polyphenolic material added to the brew in the form of hops is low when compared to malt, the nature of the hop and way they are processed in the brewhouse means a greater proportion is dissolved in the wort. The weight of polyphenols in the hops added will only be 2
3% of total in the ingredients of the brew but they will contribute around 20% of the total polyphenol to an all-malt beer. Where very high levels (more than 500 g/hL) of dry hopping are undertaken, hops can contribute as much polyphenol as malt. There is also some evidence that polyphenols both contribute to the bitterness derived from dry hopping and make the bitterness already present in the beer in the form of iso-alpha-acids more harsh and longer lasting.

1.5.5 Hop products According to a leading supplier to the craft industry, hop products are not broadly accepted by craft brewers. By hop products we mean all products made with more processing than Type 90 pellets. The supplier’s view seems to be that the stigma attached to processed ingredients makes them less desirable than less processed forms of hops. Hop products do offer a route to product consistency and innovation every bit as exciting as chucking in some herbs and spices. The simplest form of hop is the whole cone. After harvest the cones must be dried as soon as possible. Undried hops turn into compost in a matter of days so the cones are dried on belt driers or kilns. Temperature is kept below 50 °C and the moisture content reduced from 80% to around 10%. Whole cone hops are the least stable of hop products and globally the least commonly used. Typical hop utilization for whole hops is the lowest of all hop products at 25
30%. Elements of brewing value decline with time to the point where the hops you use a year after the harvest will be quite different to those you received just after they were packed. Whole hops should be stored between 1 and 4 °C and oxygen should be excluded. Old, stale hops also develop a cheesy aroma which is carried over into the beer when used. The low degree of processing in whole cones does mean they can come with added extras like leaves, bits of metal hop wire, clumps of soil, small stones and the occasional desiccated mouse. It is a good idea to pass whole hops over magnets when preparing them for the brew to remove metal objects or risk problems with

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brewhouse components or metallic off notes. Despite these drawbacks whole cones do represent the purest form of hop and a number of brewers feel that the flavor and aroma provided by whole hops are superior to that of other hop products. The use of whole hops in a properly designed and operated hop back is a good way of clarifying wort as the hop material acts as a filter once the bed of hops is formed. Getting the hops and trub out afterwards is however a great deal more arduous and hazardous than removing the hop/trub cone from a whirlpool! Wort losses in spent hops are significantly higher than those in trub even if the trub is not reused in subsequent brews. The hop harvest in progress is shown in Fig. 1.11. Type 90 pellets (T90) Type 90 pellets contain 90% of the hop cone. The missing 10% is mostly the strig which is removed when the hop is processed into a pellet. The palletization process involves drying the hop to between 7% and 9% moisture and then milling them and screening out particles outside the range of 1
5 mm diameter. The milled hops are then pressed through a die and scraped off the surface of the die when the desired length is extruded. Extrusion produces heat and so the pellets need to be cooled immediately before being packed into bags in a protective atmosphere of CO2 or nitrogen to prevent further oxidation. The process flow of the pelleting operation is shown in Fig. 1.12. Because of the nature of the production process and how they can be utilized in the brewhouse T90 pellets produce a different flavor and aroma to whole hops. Some brewers prefer it, some don’t but it is pretty much impossible to flavor match a beer previously brewed using whole hops with another using T90s and vice versa. Typical hop utilization for T90s is 30
35% (Fig. 1.12). Type 45 pellets (T45) Type 45 pellets contain 45% of the original hop material. They are also known as lupulin enriched pellets. They are made by freezing the hops at 235 °C and then milling them. Sieves are then used to select a particle size of around 0.15 mm which contains almost all the lupulin glands and very little strig and bract. T45 pellets offer easier access to the desirable aspects of the hop cone while minimizing the amount of polyphenolic material extracted. T45 pellets have about 10% greater yield of alpha acids when compared to cones. Type 33 pellets which are further lupulin enriched are also available. As is lupulin enriched powder.

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Figure 1.11 The hop harvest.

A recent “innovation” from Yakima Chief Hops takes enrichment a stage further with the production of lupulin powder. This is produced in the same way as T45 and T33 pellets, by freezing and removing of the majority of the bract material. They claim the Cryohop powder enables brewers to minimize hop-derived astringent and vegetal flavors. They also sell the waste material from the process as Debittered Leaf. One would assume that's for brewers who want hop-derived astringent and vegetal flavors in their beer.

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Figure 1.12 Type 90 pellet production process flow.

CO2 extract Hop extract is produced as a batch process in which liquid or supercritical carbon dioxide (CO2) is used as a solvent to extract the soft resins and oils. They are more stable than whole or pellet hops and are free of polyphenols and nitrates. They are also lower in pesticide residues. Using extracts exclusively can cause problems with trub removal in whirlpools and centrifuges as there is less mass in the hop material to remove. Also combining hop extract with the use of high levels of low polyphenol extract like maize starch or sugars means that there is not sufficient polyphenolic material in the beer to remove proteins or reduce oxidative damage to aroma. The extract comes in tins and is a gloopy yellow green liquid. The aroma of a beer brewed with extract is different to one brewed with whole hops or pellets so they are more suited to bitterness additions than late hopping unless the beer is a new brand. Preisomerized pellets Pre-isomerized hops are made by adding magnesium oxide to the powdered hops before palletization. The magnesium stabilizes the hops by forming salts with the alpha acids. Once the pellets are formed they are maintained at 45
55 °C for 10
14 days during which time isomerisation takes place. Pre-isomerized hops provide an improved hop utilization in

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the boil with up to 60% utilization possible in the right circumstances. They are also more stable in storage with less change in brewing quality seen over time stored. Hop oils Hop oil products are produced by distilling and then collecting the more volatile elements in the CO2 extract. The component oils are then blended to provide a proprietary product. It is possible to add them into the boil as well as pre- and post-fermentation. Recovery rates (the aromatic version of hop utilization) in the boil are not good and later additions require the use of the carrier propylene glycol which will ring alarm bells with sensitive consumers. The Pure Hop Aromas (PHAs) are a trademarked hop aroma product sold by Barth Haas and come ready diluted with propylene glycol. As hop oil products are produced to specification they offer the capability to make a more consistent hop aroma in a beer than the use hop of cones or pellets provides. Whether this aroma is superior or inferior to that of less processed hops is open to debate. Isomerized extract If hitting your BU spec is vital, isomerized extract can be used to adjust the level of a beer brewed deliberately under bitter into spec. When added before final filtration you can get 85
90% hop utilization making it a significantly cheaper way of bittering your beer than other forms of hop. Reduced iso alpha acids Reduced iso extracts were developed to enable brewers to put beers in clear or green glass without it suffering from the lightstruck off note. They are iso-extract which has been chemically reduced (the opposite of oxidized) with hydrogen to change the side chain of the iso-alpha acid molecule which is cleaved by ultraviolet (UV) light to produce the offnote. The reduced iso-alpha acids are poorly soluble in beer so require a relatively elaborate method of dosing. Their poor solubility does however mean they have a positive impact on foam stability. The heads they produce are so persistent that they can appear artificial but they do provide excellent lacing down the glass. The reduced iso products also have different levels of perceived bitterness to iso-alpha acids. Fig. 1.13 summarizes these different levels. The compound which produces the lightstruck offnote has such a low flavor threshold that if you use reduced extracts to

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produce light stable beer you do need to exclude any trace of iso-alpha acid from the beer, unless you and your consumers can live with some lightstruck character. You must therefore use only reduced extracts and also CIP everything before brewing the beer to prevent iso-alpha acid contamination. The yeast used must not have been used to ferment beer made with “normal” hops or hop products because the iso-alpha acid adsorbed on the yeast surface will be sufficient to give rise to the off-note when dissolved in beer and exposed to UV light. You also need extremely tight control of cleanliness if using them exclusively as post fermentation bitterness because you do not have the bacteriostatic protection of the iso-alpha acids in the wort (Fig. 1.13). Reduced iso product Rhohydro-iso-α-acids Hexahydro-iso-α-acids Tetrahyro-iso-α-acids

Comparative sensory bitterness vs BU x0.7 x1.3 x1.7

Figure 1.13 The relative bitterness of the reduced iso products.

1.5.6 Varieties Unlike malt varieties there can be no question that the differences between hop varieties are significant to the aroma/flavor of your beer. A discussion of all varieties is well beyond the scope of this book. All the hop merchants’ websites have colorful and informative pages covering each varieties lineage, agronomics and technical profile which is a good place to start learning what each of them can deliver to your beer.

1.6 Commercially available yeast and bacteria Dried yeast used to be for making bad bread at home. Advances in processing stemming from the understanding of cell membranes and the protective effect of the sugar trehalose means that dried yeast offers consistent fermentations without the cost of yeast handling equipment or labor. It is however a very expensive way of buying yeast especially if pitched at the rate recommended by the supplier. Despite the manufacturer’s recommendation that wort oxygenation is not necessary and the dried yeast should not be cropped and repitched, many small breweries do both with a good outcome. Great care must be taken to follow the rehydration instructions provided by the supplier prior to pitching otherwise slow or poor fermentations may result.

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Liquid yeast is available at a range of scales with some suppliers providing better quality/consistency than others, it’s worth having a chat with other craft brewers near to you to see who they use. In the UK several labs offer a service to maintain and propagate a yeast strain for you if you want to use the same strain, or offer a range of yeast types. There is also a national yeast bank which holds over 4000 strains some of which you can purchase for propagation. In the USA Whitelabs also offer 68 brewing and wine strains. You should take the descriptions of the characteristic flavor produced by each strain with a pinch of salt. Despite several claims by the suppliers, a yeast which can make a beer taste more malty is yet to be discovered. If you want a malty beer you are better off using malt! With the trend for sour beers Lallemand are applying their expertize in the supply of bacteria for wine production to supplying bacteria for use in brewing. They produce a range of dried bacteria for inoculating wort or beer. German brewing university labs also supply lactic acid bacteria for biological acidification and sour beer production Fig. 1.14 shows a range of bacteria and the flavors produced by them at different fermentation temperatures. There is little scientific information available about the use of bacteria in beer other than in the production of lactic acid for pH adjustment. What constitutes a commercially desirable sourness in beer is still being defined or redefined. Buying-in commercial strains of bacteria is far less risky than using live yoghurt or sacks of malt which has the potential to produce carcinogenic compounds in your beer. As modern craft brewing embraces novel ingredients with a bold enthusiasm, the responsibility of the brewer to keep the customer safe from hazardous and allergenic materials should be the last thing to be dismissed in the persuit of the boundary to be pushed.

1.7 Recommendations for procurement of raw materials Any successful brewer counts his suppliers as friends. Suppliers are a source of industry gossip, market updates and lots of freebies. They and their websites are a mine of technical knowledge and information. They often know what they sell inside out but it is wise to remember they are trying to sell you something before following their advice to the letter. Optimization visits from some process aid suppliers curiously tend to end in increased spending on their products, funny that! A lot of suppliers will be selling you the same things at more or less the same price. In that

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Figure 1.14 Sensory characteristics for a Range of Lactobacillus working at a range of temperatures on a standard wort. Courtesy of Lallemand.

instance areas of value added, quality, service and delivery should be the criteria for choosing your principal suppliers of each ingredient. Maintaining dialogue with as many suppliers for each raw material as possible strengthens your hand when it comes to price negotiations and will enhance the breadth of your knowledge. There are a few one-stop-shop style suppliers who do everything from hops to toilet brushes. They are great if you don’t have enough time to breathe let alone email or call 10 different suppliers each week, but are seldom best value for what you need. Buying from as far up the supply chain as your size will allow is always the cheapest way but may not always help keep the business cash rich. The further up the supply chain you go, the larger the minimum order. For hops and malt it is wise to contract to ensure you get what you need at a good price. Spot prices are generally always greater than contract, at least on the basis of recent years. Contracting into the future by a few years is usual for larger brewers and has the benefit of enabling you to plan costs over that period and protects the business from price hikes which can arise from poor crop yields or

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farmers deciding to grow something else. The downside of extended contracts is that they also protect the business from saving money when there is a good crop yield or over supply and sometimes you commit to purchase more than you will ever use. Many brewers contract 100% of their projected requirement for year 1, 50% for year 2% and 25% for year 3. As a small brewer, projecting your requirement is often the hardest bit and it is very unusual to get everything spot on. Contracts are legal documents which oblige each party to stick to their side of the bargain but it is very unusual for suppliers to hold smaller breweries to contracts where they have slightly overegged volumes. It is therefore wise to go long on what you require although don’t sue me if your supplier gets contractual! Malt will, even in times of extremely high hop prices, constitute your biggest spend. The price of malt is tied to the price of barley and this is affected by global demand for cereals. From one year to the next what you pay for malt may be impacted upon by factors as diverse as droughts in Russia or a surge in demand for bioethanol. It is therefore imperative to keep an eye on the markets while considering when and how much to contract.

Helpful definitions Flavour threshold the lowest concentration of flavour active substance at which humans can detect it Isomers molecules with the same formula but with a different arrangement of atoms Protein a large molecule made up of amino acids Polypeptide a long chain of peptides Peptide a short chain of amino acids Glucose a sugar with 6 carbon atoms Maltose a sugar made up of 2 glucose molecules Fructose a sugar with 5 carbon atoms Sucrose a sugar made up of fructose and glucose Starch a large molecule made up of strings glucose molecules Glucan a gum made up of glucose molecules Oxidation the addition of oxygen to an organic molecule Catalysed when a chemical reaction is facilitated by a catalyst/enzyme Substrate a compound taking part in a chemical reaction. In the case of enzyme catalysed reactions the enzyme will interact with the substrate to facilitate or speed up the reaction Lysis a reaction involving splitting two molecules New world hops hops from USA, Australia, New Zealand and South Africa