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Brewing with Amylase

  a-Amylase;The principal functions of  the a-Amylase in beer-making are to thin the mash during the cooking process and to provide fermentable sugars,glucose,maltose and the next higher triaose,maltotriose for the yeaset.After gr inding,sa portion of the total malt to be used in mixed with adjuncts such as rice,corn and more recently wheat.Water is added and the resulting mash is boiled to swell and gel and finally disrupt the starch granules.At the start of the heating,the  a-Amylase is acting on raw starch granules.In a thorough study of the degradation of  both barley and malt starch granules under conditions simulating those of a conventional infusion mash,showed that the intact’’raw’’ granules from malt are more susceptible to malt  a-Amylase than are granules from ungerminated barley.They attribute this difference as well as granule-size dipendent difference in susceptibility to prior modification.The temperature of the mash infusion is then reduced to 65°C and the remainder of the malt is added. a-Amylase action in cooperatation with that  of β-amylase produces an optimum amount of fermentable sugars plus sizable amounts of dextrins,with the a-Amylase controlling both rate extent of starch  degradation.For standart beers,one does not utilize the full potential of the combined action of these two amylases mainly because the alcohol level in the resulting beer would be to high.Dextrins,partially degraded amylose and amylopectin,which constitute about one-quarter of the total carbohydrate of a conversional brewers wort,tradiitional impart and contribute to foamability of the final product.Of  the remaining carbohydrates in the wort 11%is glucose,50% are disaccharides,mostly maltose,and 14%trisaccharides.About 5%of these fermentable carbohydrate becomes yeast and the remainder is converted into equal amounts of the CO2 and ethanol.