BEER- TYPES, PRODUCTION & SPOILAGE PALLAVI DHOTRA ROLL NO. 06 FOOD SCIENCE & TECHNOLOGY
INTRODUCTIONBeer is the world’s oldest & most widelyconsumed alcoholic beverage.It is 3rd most popular drink after water &tea.The process of making beer is known asbrewing.Beer is produced by fermentation ofstarches derived from cereal grains.The alcoholic strength of beer is usuallyaround 4% to 6% alcohol by volume (ABV).
TYPES OF BEER BEER ALES LAGERPALE MILD LIGHT DARK STOUTALE ALE LAGER LAGER
INGREDIENTS FOR BEER PRODUCTIONMaltHopsBrewer’s YeastBrewing WaterAdjuncts
MALTING Barley Cleaning Sorting Large Medium Small Animal feed Steeping in water (at 12-15°C for 2-3 days) GerminationDrying of malt (at 71-92°C) Curing of malt (at 80°C for 5 hours) Grind to coarse flour
MASHING Mashing is the process where cereal grist is mixed with hot water to extract sugar for fermentation. The product of mashing is termed as sweet wort. The process of mashing involves:-i. Dissolving the substances in the malt that are soluble in warm water.ii. Rendering the substances which are insoluble in their natural state or soluble through enzymatic action.
WORT FILTRATION The process of separating the liquid part of mash (wort) from the undissolved part (the spent grain) is called lautering. Two types of equipments are used to separate wort from mash solids, these are:-i. Lauter Tun:- It is a vertical cylinder with a large diameter to depth ratio and fitted into the tun is a wort collecting system.ii. Mash Filters:- The mash filters consists of a series of alternating plates and roller frames in which a filter of polyethylene or polypropylene is suspended.
WORT BOILING & HOP ADDITION Wort boiling involves open top vessels, operating at atmospheric pressure, which exploits thermosyphon circulation to keep the wort well agitated. During boiling hops are added which impart flavor, aroma and bitterness to the beer. The objectives of wort boiling are:-i. Enzyme inactivationii. Wort sterilizationiii. Protein coagulation (hot break formation)iv. Hop extractionv. Water evaporationvi. Flavor compound formationvii. Undesired volatile evaporation
HOP SEPERATION & COOLINGAfter boiling, wort is passed through hopseparator to remove both hops andprecipitated proteins (trub).The wort is cooled to 10-15°C, in a plate heatexchanger.During cooling process, proteins and tanninsare precipitated as fine coagulum referred toas the ‘cold break’.During cooling the oxygenation of the wort iscarried out to permit the yeast to fermentefficiently.
FERMENTATIONAfter cooling the wort is ready for fermentation & ismoved to fermenter.Brewer’s Yeast is inoculated into the cooled wort.For ale production Saccharomyces cerevisiae is inoculated &for lager production Saccharomyces uvarum is inoculated.As fermentation proceeds specific gravity is decreaseddue to the utilization of carbohydrates by the yeastThere is production of ethanol and other compoundswith density less than water.Carbon dioxide is also evolved during fermentationwhich is utilized for carbonation.When yeast settles down, the beer obtained is calledGreen Beer which is subjected to another storage tankhaving temperature 0-2°C. This stage is called fassing.
AGEING & FINISHINGAgeing involves the storage of beer in vats havingtemperature 0°C, during which beer is mellowedor matured.Finishing involves the clarification of beer toremove residual yeast & residual protein-tannincomplex.Hops are also added to retain the flavorSecondary fermentation is done if required as apart of ageing to make beer fully carbonated.After final fermentation beer is packed in cans &bottles and is pasteurized at 60°C for 30 minutes.
SPOILAGE OF BEER Beer spoilage is caused due to following reasons:-i. Spoilage caused by bacteria:- lactic acid bacteria, acetic acid bacteria, Zymomonas anaerobia, Pediococcus cerevisiae causes beer spoilage.ii. Spoilage caused by wild yeast:- wild yeast causes spoilage at any level of beer production, such yeasts are- Saccharomyces diastaticus, Candida lambica, Dekkera intermedia. In production of ales, Saccharomyces uvarum acts as a wild yeast where as in production of lagers Saccharomyces cerevisiae acts wild yeast.