Potential techniques for improving brewhouse yield.

Van Gheluwe, G. and Valyi, Z.

Abstract
The problem of brewhouse yield was, up to a few years ago, not too important in the North American or Canadian context. This situation has changed completely in recent years. In this connection, it is imperative to minimise sewer losses since the brewing industry cannot afford to lose extract and, equally importantly, we cannot afford to treat sewage. Recycling into the mash, of all yeast produced, the grain press effluent, the hot wort sediment and the spent diatomaceous earth used for beer filtration was carried out successfully on pilot scale. A substantial increase in yield of 2.6% was obtained. Taste panel tests showed no significant overall difference. Changes taking place during mashing are due to the joint action of several enzyme systems. Some of these enzyme systems are inactivated through the malt kilning process. Enzymes naturally produced by using microbial entities are, therefore, interesting to us as a supplement of the missing enzyme systems. Mashing experiments were carried out using various species of fungi or bacteria as external enzyme source in an all malt mash. Increases in extract yield as high as 7.7% were noticed. Suitable fungi or microbial species could be produced under optimal conditions in industrial fermenters and used as external enzyme source. These microbial species could be grown almost continuously to supply the required enzyme source for mashing.
Keywords: brewhouse brewing costs enzyme filter aid mashing recycling wort