ABSTRACT
The objectives of brewer's wort fermentation are to consistently metabolize wort constituents into ethanol, carbon dioxide, glycerol, and other fermentation products in order to produce beer with satisfactory quality, stability, and drinkability. Free amino nitrogen (FAN) is the sum of the individual wort amino acids, ammonium ions, and small peptides (di- and tripeptides). The fermentable wort sugars (sucrose, fructose, glucose, maltose, and maltotriose) comprise the largest component of solid material in solution. The concluding stages of a brewing wort fermentation overlap with maturation. The principal fermentation mode employed globally is batch. A stratified fermentation is where two or more separate and distinct fermentations occur in a fermenter at the same time. Continuous fermentation requires ongoing laboratory monitoring and automatic control of flow rates, temperature gradients, yeast recycle rates, potential bacterial and wild yeast contamination, and oxygen levels.
