Brewing operations
Milling of malt -> |
Mashing (converting the starch)-> |
Wort separation (filtering the mash) -> |
Wort boiling (boiling, adding hops) -> |
Trub separation (whirlpool) -> |
finished wort (cooling to fermentation) |
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Mashing (important step, time and temp) |
Infusion mashing: one vessel |
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Decoction mashing: two vessels, better if you can't control temps |
Grist load |
20% spent grains |
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out of the rest, 65% are fermentable sugars, rest are not |
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maltose, maltotriose, fructose, glucose, sucrose |
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unfermentable are dextrins, protiens, gums, pentose, minerals |
Lautering
Lauter tun or mash filter |
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First wort - sparging - last runnings - spent grain removal |
boil wort |
4-10% evaporation, boiling about 60 mins, hop added |
Milling
Objectives |
crush husks to expose endosperm |
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completely disentegrate endosperm to make all constituent available for enzymes |
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keep fine powder at minimum |
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Prevent extraction of unwanted substances during mashing |
Milling types |
Hammer mill: fine pieces. used for mash filters |
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Roller mill: husk not damaged, must be used for filtering |
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From wort to final beer
Whirlpool -> |
cooling wort -> |
wort aeration -> |
yeast pitching |
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Pitching: yeast is mixed with wort |
Ale or top fermenting yeast |
vs Lager or bottom fermenting yeast |
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The yeast converts fermentable carbohydrates in the wort into alcohol and carbon dioxide |
Objectives of mashing
Aim |
to form an extract with a desired profile of sugars and a desired level of proteins, amino acids and other minor chemical constituents |
Purpose |
To dissolve immediately soluble substances. This fraction constitutes approximately 15% of the total ingredients. |
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To convert substances that are initially insoluble in the mash into soluble substances, through enzymatic action. |
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To convert the extracted substances into fermentable extract, through enzymatic action. |
alfa amylase |
cuts big pieces |
beta amylase |
cuts in parts of two |
iodine test |
shows positive test for starch |
Heating jacket |
Limpet coil |
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Dimple jacket |
Lauter tun |
Principle: filtration through a bed of grains |
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Compared to mash filter: • more flexible – variation in brew types and sizes • less expensive • lower yield |
Mash filter |
Principle: • filtration takes place through a filter cloth |
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Compared to lauter tun: • less flexible – variation in brew types and sizes • more expensive • higher yield |
Purpose of Wort Boiling and Hopping |
Conversion of bitter components in hops from insoluble form to water soluble form – isomerisation of hop α-acids • Extraction of hop aroma • Sterilization of the wort • Adjustment of strength (% Plato) by evaporation • Removal of unwanted aroma components – DMS • Precipitation of proteins and polyphenols – trub, break • Inactivation of any remaining enzymatic activity |
Hopping |
Bitter hops: Hops added in beginning of boiling |
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Aroma hops: Hops added at end of boiling |
Wort cooling |
Coolship |
big shallow trough |
Plate heat exchanger |
Hot wort runs next to cold water. hot water is recycled, fx in CIP |
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Malt, hops, Water and Adjuncts
Barley -> Malt |
Two-row barley and Six- row barley (two-row better) |
Barley composition |
Embro |
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Leaf |
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Endosperm |
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beta glucan walls |
aleurone |
production of enzymes 71% arabinoxylan 26% ß-glucan |
Endosperm |
Storage of starch 75% ß-glucan 20% arabinoxylan |
Steeping |
grain take up water |
Germination |
enzymes activated and synthesised, cells walls and protein broken down |
Kilning |
heating to stop enzymatic activity, production of colours and flavours |
Barley Handling |
Pre-cleaning, De-stoning, Removal of half grains and weed seeds, Screening |
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Hops (only female hops) |
Bitterness, aroma, taste stability |
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antioxidants, antibacterial |
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foam, cling, lacing |
Growth |
Upwards, harvested bottom to top |
Hop products |
Pellets |
Pellets (90 and 45) |
Isomerised |
Iso-pellets |
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IKE Isomerised Kettle Extract |
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PIKE Potassium Isomerised Kettle Extract |
Downstream |
ISO extract |
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RHO, Tetra, Hexa |
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Hop Oils and Fractions |
Special products |
Lupulin glands |
Alpha and beta acids, xantohumol |
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isomeresation of alpha acids increases solubility and bitterness. also makes the light struck flavour |
Water |
At least same quality as drinking water |
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Opimization of minerals (disolved ions) -> Hardness |
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ptimization of pH -> Alkalinity |
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bottom fermented beers (lagers) are brewed with soft water |
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top fermented beers (ales, stouts, etc.) on hard and mineral rich water. |
Ground water |
very clean, stable low temperature, often very hard but depends on ground composition |
Surface water |
more particles and microorganisms, varies in temperature, often very soft |
Town water |
Really well balanced |
Hardness |
Temporary end permanent depending on mineral salts |
Adjuncts |
Types |
Peas, Rice, Corn flakes, rye, soya |
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“ANY CARBOHYDRATE SOURCE OTHER THAN MALTED BARLEY WHICH CONTRIBUTES SUGARS TO THE WORT” |
Quality |
Taste and Flavour Stability • Head Retention • Colour • Degree of Fermentation • High Gravity Wort |
Economy |
Price of the adjunct versus malt • Influence on brewing capacity • Energy savings • Taxation |
Gelatinisation |
Some adjucts gelatinise at higher temps than malt, so it has to be boiled seperately |
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