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ICC Brewing School December 2016 ICC Brewing School
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ICC Brewing School Syllabus:
Module 1 – Raw Materials and Grist Preparation Module 2 – Wort Production, Fermentation and Yeast Module 3 – Conditioning, Filtration and Bright Beer Module 4 – QA and Utilities Module 5 – Beers of the World December 2016 ICC Brewing School
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Raw Materials and Grist Preparation
(Malted) Barley Adjuncts Hops Water Milling December 2016 ICC Brewing School
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Barley Main raw material used in beer production
Provides sugars for fermentation Grain contains carbohydrates as starch – food for the growing plant during germination Starch granules embedded in protein matrix, held together by cell walls made up of cross-linked β-glucan gum – protects starch from exogenous amylase enzymes that would otherwise rapidly break it down December 2016 ICC Brewing School
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Barley Corn December 2016 ICC Brewing School
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Malting 3 Stages: Steeping – grain soaked in water to simulate conditions in nature that start germination Germination – grain allowed to germinate under carefully-controlled conditions to ensure homogeneity and minimize losses Kilning – green malt heated to dry it, to stop germination and to ‘freeze’ enzyme activity December 2016 ICC Brewing School
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Steeping False-bottomed, conical tanks
Aerated from bottom – ensures even moisture uptake and prevents asphyxiation Periods of soaking (2-3) followed by air rests – total time hours Water content raised from 12% to 45% Produces wastewater with very high BOD December 2016 ICC Brewing School
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Germination Plant shoot and roots begin to grow
Hormones stimulate production of enzymes in the aleurone layer These enzymes break down cell walls (β-glucanases) and protein matrix (proteinases) exposing starch granules – referred to as ‘modification’ Degree of modification influenced by moisture content, temperature and time allowed in germination Lager malt generally ‘under-modified’; ale malt generally ‘well-modified’ Effect of modification on process requirements will be seen later December 2016 ICC Brewing School
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Germination December 2016 ICC Brewing School
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Germination Flat-bottomed rectangular or circular tanks
Temp. and moisture controlled using moist air pulled through from below bed 3-5 days Turners ensure even germination and prevent matting of rootlets December 2016 ICC Brewing School
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Floor Malting December 2016 ICC Brewing School
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Kilning Drying – water content dropped to 4% – low temp / high air-flow inactivates, but does not destroy, enzymes At moisture of 10%, heat may be increased to varying amounts depending on color and flavor required Allows long-term storage without deterioration Flavor/color development – heat-based reactions between sugars and soluble proteins Flat-bottomed circular vessel (older designs are rectangular) Indirect fired, with glass tube heat exchangers to recover energy from exhaust air Modern maltings may use combined germination/kilning vessels (GKVs) December 2016 ICC Brewing School
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Kilning December 2016 ICC Brewing School
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Adjuncts Solid or liquid materials used to supplement malt Used to:
Impart specific character (flavor, color, head retention) to beer Increase capacity of brewhouse (liquid) Reduce cost Examples: Colored and crystal malts – increase color, modify flavor Roasted barley – especially in stouts Malted wheat – main ingredient in Weissbier Wheat flour – improves head retention, much cheaper than malt Corn (maize) grits – dilutes ‘maltiness’, gives ‘clean, delicately flavored’ beer – must be cooked in the brewhouse Rice – (see corn) Sugar (sucrose) and high-maltose syrups – add capacity at much lower cost – alter fermentability December 2016 ICC Brewing School
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Hops Humulus lupulus – flowering plant in the Cannabaceae family
First documented use of hops in beer is from 9th C. Germany though didn’t come into common use until the 12th C. For centuries, brewers used ‘gruit’, composed of a variety of bitter herbs and flowers, including dandelion, burdock root, marigold and heather Gruit is believed to have been abandoned when beers made with hops were noticed to be less prone to spoilage (due to the anti- microbial effect of the hop resins) The hop plant is a vigorous, climbing, herbaceous perennial; many varieties of hops are grown around the world, with different types being used for particular styles of beer December 2016 ICC Brewing School
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Hop Characteristics Bitter resins (α-acids) and oils develop around seeds α-acids isomerized during wort boiling – become more soluble and more bitter – measured as ppm of iso-α-acid (IBUs) Oils – aromatic – give beer ‘nose’ and character – very volatile so added at end of boil Major brewers tend to opt for high α-acid varieties where cost of bittering is key Smaller brewers usually mix bitterness and aroma – higher cost per barrel but more character December 2016 ICC Brewing School
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Hop Products Whole hops – ‘traditional’ – lose brewing value in storage – bulky Hop pellets – contain all essential material of original hops – vacuum packed to preserve freshness – known α-acid content – easy storage Hop extract – α-acids extracted using liquid CO₂ – known α-acid content – very easy storage Pre-isomerized hop extract – ground hops heated in presence of (usually) magnesium oxide – product is more stable and brewing losses are reduced compared to ‘normal’ extract Reduced pre-isomerized extract – not susceptible to degradation by u.v. therefore suitable for beers packed in clear bottles December 2016 ICC Brewing School
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Brewing Water Beer is, on average, 95% water
Must be plentiful and reliable Quality requirement Achieved through… Clear, colorless Sand filtration Odorless, taint-free Carbon filtration (especially Cl-) Free of microbial contamination UV sterilization; ultra-filtration; addition of ClO₂ Pesticide-free Reverse osmosis Consistent mineral salt content Consistent supply or ion-exchange and add back Salt / mineral Effect on process / product Chloride Palate ‘fullness’ Sulfate Lowers mash pH (good for enzymes); imparts “dryness” Calcium Yeast nutrient; aids haze stability Magnesium, zinc Yeast nutrients Iron Induces haze; metallic flavor Carbonate Raises mash pH; forms scale on heating surfaces December 2016 ICC Brewing School
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Milling Prepares malt for mashing and makes starch accessible
Different types of mills used for different production processes Six-roll mill Common in older and more ‘traditional’ breweries Gives finely ground kernel while preserving the husk Used with well-modified malt Wet mill Malt steeped in water before milling Allows fine grind with minimal husk damage Used with under-modified malts No grist case required Hammer mill Produces fine grind Only used where mash is to be separated in a mash filter Used with under-modified malts and other cereal adjuncts December 2016 ICC Brewing School
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Six Roll Mill December 2016 ICC Brewing School
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Wet Mill December 2016 ICC Brewing School
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Hammer Mill December 2016 ICC Brewing School
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Grist Quality of grist has major impact on brewhouse performance
Too coarse – starch remains protected – amylases unable to convert starch to fermentable sugars Too fine – mash separation problems (not applicable to mash filters) Standard sieve analyses used for different brewhouses – roller gap adjustments made by brewer to ensure maximum extract efficiency December 2016 ICC Brewing School
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Safety Malt dust is hazardous – can cause breathing problems – fine dust explosive when suspended in air Housekeeping important to keep risk of explosion low Non-sparking tools, explosion-proof switches, plastic conveyor buckets... Safe systems of work, hot-work permits, fire watches… Modern malt handling areas fitted with explosion doors/panels to direct blast safely outward Malt conveyors fitted with slip-detectors, bearing heat sensors, rotary valves (prevent explosions propagating) December 2016 ICC Brewing School
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