TECHNOLOGY OF CEREALS Beers Made from Wheat-Malt and their Characteristics T Character Origin Alcohol Flavour features Weizenbier Lager/Ale Bavar Full bodied, low hops Hoegards wit Full bodied bitter ource: Pomeranz, 1987, citing information from A. A. Leach of the Brewers' Society, U.K worts were turbid owing to proteinaceous materials. sugars. Hops are also added at this stage. As well Malt yields were between 87 and 90% as adding flavour they serve to sterilize the wort and participate in reactions that precipitate proteins Brewing responsible for haze when the wort is boiled Boiling may continue for 1.5-2h during boiling Beer the humulone or a-acids are isomerized to the bitter iso-a-acids. As the yield of bitter iso-a-acids Wort production extracted from the hops by boiling may be as lor as 30%, a modern procedure is to replace part of the The starting material for brewing may be pure raw hops by a pre- isomerized hop extract, which is (usually barley) malt, or a mixture of malt and added to the beer after fermentation. It is com- djunct. If solid adjuncts are to be included they mon for half the hops to be added at the beginning may be milled with the malt. The coarsely ground of the period and half at the end. The wort is material, on hydration with brewing liquor, cooled (to 15.5% C for British ales or to 4-7C produces a brewers'extract from the solubles, for pilsners and lagers), filtered and transferred to and a filter bed from the husk. The quality of pitching tanks where it is ' pitched with yeast (i.e the filter bed depends on the size of the husk yeast is added). Air is also passed into the hopped particles; they should not be too fine. The process wort to provide a supply of oxygen for the yeast is known as mashing and it is carried out in vessels which rapidly becomes active(added oxygen called mash tuns removes the lag phase that would otherwise occur) After an initial rest for hydration to be completed the temperature is raised above the gelatinization fermentation much more susceptible to digestion by amylase Yeasts vary in their behaviour during ferment enzymes, to produce soluble sugars. The process tion, some strains tend to flocculate, as a result of conversion, begun during malting, thus con- they trap CO2 and rise to the top Others, which tinues during this phase. do not flocculate. sink to the bottom. Several It is now necessary to separate the liquid wort styles of lagers are produced by bottom fermenta- from the solid remains of the malt and adjuncts, tion while many types of ales and stouts are and this is done by a process called lautering,. produced using top fermentation. Examples are The spent grains act as a filter bed when the given in table 9.4 mixture is transferred to a lauter tub, which has An efficient type of fermenter is a deep a perforated bottom. The spent grains accumulate cylindrical vessel with a conical base into which this and allow the liquid to pass through while the yeast eventually sediments. In such vessels retaining the fine solids. The sugary liquid is the liberation of carbon dioxide provides efficient known as the 'sweet wort' it is supplemented agitation, allowing cycles of filling, fermentation, with syrups at this stage if such adjuncts are to emptying and cleaning to be accomplished in 5 be used to increase the amount of fermentable days at 12 C or 2.5 days at 18C226 TECHNOLOGY OF CEREALS TABLE 9.3 Beers Made From Wheat-Malt and their Characteristics Type Character Origin Alcohol Flavour features (Yo v/v) Weizenbeer LageriAle Bavaria 5-6 Full bodied, low hops Weisse Lager Berlin 2.5-3 Light flavoured Gueuze-Lambic Acid ale Brussels 5+ Acidic Hoegards wit Ale East of Brussels 5 Full bodied, bitter Source: Pomeranz, 1987, citing information from A. A. Leach of the Brewers' Society, U.K. worts were turbid owing to proteinaceous materials. Malt yields were between 87 and 90% sugars. Hops are also added at this stage. As well as adding flavour they serve to sterilize the wort and participate in reactions that precipitate proteins responsible for haze when the wort is boiled. Boiling may continue for 1.5-2 h. During boiling the humulones, or a-acids are isomerized to the bitter iso-a-acids. As the yield of bitter iso-a-acids Beer extracted from the hops by boiling may be as low Wort production as 30%, a modern procedure is to replace part of the The starting material for brewing may be pure raw hops by a pre-isomerized hop extract, which is (usually barley) malt, or a mixture of malt and added to the beer after fermentation. It is com￾adjunct. If solid adjuncts are to be included they mon for half the hops to be added at the beginning may be milled with the malt. The coarsely ground of the period and half at the end. The wort is material, on hydration with brewing liquor, cooled (to 15.5"-18"C for British ales or to 4"-7"C produces a brewers' extract from the solubles, for pilsners and lagers), filtered and transferred to and a filter bed from the husk. The quality of pitching tanks where it is 'pitched' with yeast (Le. the filter bed depends on the size of the husk yeast is added). Air is also passed into the hopped particles; they should not be too fine. The process wort to provide a supply of oxygen for the yeast is known as mashing and it is carried out in vessels which rapidly becomes active (added oxygen called mash tuns. removes the lag phase that would otherwise occur). After an initial rest for hydration to be completed Fermentation the temperature is raised above the gelatinization temperature of the starch. This renders the starch much more susceptible to digestion by amylase Yeasts vary in their behaviour during fermenta￾enzymes, to produce soluble sugars. The process tion, some strains tend to flocculate, as a result of conversion, begun during malting, thus con- they trap C02 and rise to the top. Others, which tinues during this phase. do not flocculate, sink to the bottom. Several It is now necessary to separate the liquid wort styles of lagers are produced by bottom fermenta￾from the solid remains of the malt and adjuncts, tion while many types of ales and stouts are and this is done by a process called 'lautering'. produced using top fermentation. Examples are The spent grains act as a filter bed when the given in Table 9.4. mixture is transferred to a lauter tub, which has An efficient type of fermenter is a deep a perforated bottom. The spent grains accumulate cylindrical vessel with a conical base into which on this and allow the liquid to pass through while the yeast eventually sediments. In such vessels retaining the fine solids. The sugary liquid is the liberation of carbon dioxide provides efficient known as the 'sweet wort'; it is supplemented agitation, allowing cycles of filling, fermentation, with syrups at this stage if such adjuncts are to emptying and cleaning to be accomplished in 5 be used to increase the amount of fermentable days at 12°C or 2.5 days at 18°C. Brewing