INTRODUCTION TO BREWING AT FULLERS docx

1 INTRODUCTION TO BREWING AT FULLERS 2 CONTENTS BREWHOUSE 5 • Brewing Liquor 6 • Raw Materials 7 • Milling 8 • Mashing 9 • Extract 12 • Starch Degradation 13 • Wort separation 15 •Hops 16 • Wort Boiling 18 • Wort Clarification & Cooling 19 • Wort Analysis Examples 20 FERMENTATION 21 • Carbohydrate Metabolism 23 • Nitrogen Metabolism 24 • Fermentation Profiles 25 • END PROCESSING 27 • Beer Conditioning 28 • Cask Beer 30 • Conditioning / Racking • Tank 32 • Filtration Aids 33 •Filtration 34 • Bright Beer Tank 36 • Small Pack Quality Control 39 • Bottling 40 • Canning 42 • Pasteurisation 44 • Kegging 47 • End Processing Food Safety 48 C. I .P 49 RECOMMENDED READING 51 3 MALT SILO FLASH PASTEURISER BOTTLES / CANS OR KEGS FERMENTATION THE BREWING PROCESS BREWING LIQUOR MASH TUN COPPER / WHIRL POOL MILL SWEET WORT CONDITIONING TANKS MATURATION TANKS CASKS RACKING TANKS PARAFLOW BRIGHT BEER TANKS 4 The Brewing Process • MILLING - malted barley is crushed to form a coarse flour called grist • MASHING - grist is added to liquor to form a porridge-like mash. This activates the enzymes, thus enabling them to solubilise the protein and starch fractions of the endosperm • WORT SEPARATION-the aqueous extract, called wort, is separated from the spent solids using a mash tun • WORT BOILING - the wort is boiled in the presence of hops which impart bitterness and aroma. Boiling sterilises the wort, coagulates some proteins and causes formation of colour compounds. The spent hop material along with some protein, known as trub, is removed by whirlpool action. • FERMENTATION - the wort is then cooled to 17°C and transported to the fermentation vessel. The wort is aerated & pitched with yeast. Fermentation proceeds until much of the carbohydrate is converted to alcohol and carbon dioxide. Higher alcohols and other yeast metabolites (for example esters) contribute to beer flavour and aroma. • END PROCESSING - beer is then conditioned to modify the flavour and aroma before clarifying. All beer characteristics are checked and adjusted to within specification. The beer is packaged into cask or filtered and pasteurising before being packaged into keg, bottle or can. 5 BREWHOUSE 6 Brewing Liquor • Water Treatment - removal of hardness by heating & acid addition • Direct Flavour Effects - Na + sweet (salty in excess) / Mg 2+ bitter, sour / Fe 3+ metallic / Cl - fullness / S0 4 2- astringency / K+ salty • Indirect flavour effects - yeast requirements / pH / enzymes during mashing Keep calcium >150ppm. Four times more calcium than malt oxalate required pH CONTROL • Bicarbonate more influential at raising pH than calcium at lowering • Carbonate : bicarbonate buffer system Ca 2+ H 2 0 + CO 2 HCO3- CO 3 2- CaCO 3 • Calcium : malt buffering system 3 Ca 2+ + 2 HPO 4 2- 2H + + Ca 3 (PO 4 )2 Polypeptide H + Ca 2+ Polypeptide Ca + 2 H+ • High bicarbonate high wort pH due to removal of H+ • Calcium reacts with malt protein to reduce wort pH / increased run-off rate / increased extract recovery / increased TSN & FAN / precipitation of oxalate 7 Raw Materials Pale Ale Malt • Malted barley • Concentrated source of starch • Starch consists of unbranched helical amylose [200- 400 D-glucose units linked via α−1,4-positions] AND branched amylopectin [D-glucose units linked via α- 1,6 and α -1,4 links. Up to 6000 glucose units] molecules. • Barley starch granules : large granules supply most of the brewers extract (20 - 25µ) and small starch granules (1 - 5µ) • Barley protein : 30% glutelin (dissolves in weak alkali)+ 37% hordein (dissolves in 80% alcohol)+ 11% albumin (dissolves in water) • High molecular weight proteins : improve head retention • Low molecular weight proteins : amino acids and small peptones for fermentation are haze precursors • Fats : husk and aleurone layer e.g. stearic acid, oleic acid, linoleic acids = long chain fatty acids. Detrimental to beer foam, but required for membrane synthesis. 8 Raw Materials Coloured Malts & Adjuncts • Crystal Malt - contributes colour (150° EBC colour units)and malty / nutty / toffee / fruity notes to London Pride, Chiswick Bitter & ESB • Chocolate Malt - contributes colour & flavour to London Porter • Amber Malt - contirbutes colour (45°EBC colour units) and sweetness and dryness to 1845 • Malted Wheat - contributes fullness and fruity notes to Summer Ale along with more protein for head formation 9 Milling Mechanical breakdown of dry goods to produce grist. Preparation of grist for the mash tun Keep husk material in-tact to act as filter bed during wort recovery • Endosperm material into small particles, grits, which readily hydrate during mashing to reactivate the malt enzymes giving us maximum extract. • Dry milling - 4 roller mills with 2 pairs of contra- rotating rollers. • Proportions of coarse grits (0.3mm-0.6mm diameter):fine grits (0.15mm - 0.3mm): flour (<0.15mm) ratios vary from 27:35:38 to 24:35:41 • Gypsum (calcium sulphate) is added to the grist as it is produced (see liquor treatment page) • Grist transferred via conveyor to grist hoppers above mash tuns 10 Mashing Hydrate grist and activate enzymes to form soluble substances for fermentation • Hot liquor (69°-71°C) comes into contact with the grist in the ‘Steels Masher’ to achieve a mash temperature of 65°C in the mash tun • A porridge-like mash is formed with a bed depth of 1.5-2.0m in the mash tun • The mash tun has a false / slotted floor 5mm from the base of the vessel and the mash sits on this for 55mins. The false floor is flooded with hot liquor before mashing starts to remove the air • During this period starch is degraded by amyloytic enzymes forming sugars (primarily maltose) and protein is further degraded by proteases. The cell wall material is also further degraded by glucanases • Important flavour developments occur during mashing as a result of the starch degradation [...]... ALCOHOLS FATTY ACIDS ESTERS LIPIDS MALTOSE GLUCOSE SUCROSE invertase invertase MALTOTRIOSE maltase hexokinase, glucokinase GLUCOSE-6PHOSPHATE glucose-phosphate isomerase FRUCTOSE FRUCTOSE-6PHOSPHATE phospho fructokinase FRUCTOSE-1,6DIPHOSPHATE PHOSPHOENOL PYRUVATE pyruvate kinase Anaerobic Metabolism PYRUVATE pyruvate decarboxylase ACETALDEHYDE alcohol dehydrogenase ETHANOL 26 Beer Maturation / Conditioning... vessel to an external calandria (called the EWB=external wort boiler) for heating & returned to the vessel tangenitially (at 90°) Chemisty • Formation of bitter compounds • Wort sterilisation • Precipitation of calcium phosphate & proteins causing the pH to drop from 5.4 to pH 5.2 • Evaporation and hence concentrate the wort • Inactivation of enzymes • Formation of flavour active compounds • Formation... is a heat exchanger made up of 100 plates with chilled liquor ( . 1 INTRODUCTION TO BREWING AT FULLERS 2 CONTENTS BREWHOUSE 5 • Brewing Liquor 6 • Raw Materials 7 • Milling 8 • Mashing 9 • Extract 12 • Starch Degradation. Wort sterilisation • Precipitation of calcium phosphate & proteins causing the pH to drop from 5.4 to pH 5.2 • Evaporation and hence concentrate the wort •