Fermentation—overview, process, and technology

Abstract

The cooled aerated wort made in the brewhouse is fermented by yeast to make an immature beer (green beer). During this process, yeast reproduces. The main fermentation (primary) in which green beer and yeast are produced is often followed by a slower process at lower temperature in the presence of lesser amounts of yeast. This is referred to as secondary fermentation, conditioning, or even maturation. Finally, beer may be freed from yeast and aged (matured) at low temperature before packaging. The quality of the green beer depends upon the composition of the wort, the yeast strain and amount used, and the process and technology of primary fermentation. This product is the raw material for later processes in the brewery.