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Brewing with malted barley or raw barley: what makes the difference in the processes?

Author:
Kok, Yee Jiun, Ye, Lijuan, Muller, Jeroen, Ow, Dave Siak-Wei, Bi, Xuezhi
Source:
Applied microbiology and biotechnology 2019 v.103 no.3 pp. 1059-1067
ISSN:
0175-7598
Subject:
barley, beers, brewing, chemical composition, enzymes, malt, malting, malting barley, milling, sugars, yeasts
Abstract:
Malted barley is the main source for fermentable sugars used by yeasts in the traditional brewing of beers but its use has been increasingly substituted by unmalted barley and other raw grain adjuncts in recent years. The incorporation of raw grains is mainly economically driven, with the added advantage of improved sustainability, by reducing reliance on the malting process and its associated cost. The use of raw grains however, especially in high proportion, requires modifications to the brewing process to accommodate the lack of malt enzymes and the differences in structural and chemical composition between malted and raw grains. This review describes the traditional malting and brewing processes for the production of full malt beer, compares the modifications to these processes, namely milling and mashing, when raw barley or other grains are used in the production of wort—a solution of fermentable extracts metabolized by yeast and converted into beer, and discusses the activity of endogenous malt enzymes and the use of commercial brewing enzyme cocktails which enable high adjunct brewing.