Wort cooling, fermentation and storage in beer production

In beer production the hot, clear cast wort at around 70°C from the whirlpool is cooled in a heat exchanger typically using liquid ammonia. Once cooled down to the temperature required for adding yeast, between 5-20°C (known as the ‘pitch temperature’), it is fed into a fermentation tank with sterile air to saturate it with oxygen, while the yeast is added (‘yeast pitching’). Now the actual fermentation process takes place, over 5 to 8 days - during which 60 to 70% of the sugar in the wort is converted into alcohol and carbon dioxide. Fine dust particles and yeast suspended in the wort settle during or after fermentation and the beer becomes clear. Depending on the yeast used, top or bottom fermented beer is produced. With top-fermented beer, the yeast floats on top of the beer, with bottom-fermented yeast it sinks to the bottom. During the subsequent storage, the remaining sugar is converted into alcohol and carbon dioxide – this is the secondary fermentation. Since the storage tanks are sealed, the carbon dioxide in the beer cannot escape, and is bound as carbonic acid. This secondary fermentation takes between 2 weeks and 3 months, depending on the type of beer.

KROHNE offers various optimised solutions for flow, pressure, temperature and level measurement in these process steps. Since fermentation and storage tanks are under pressure, the level is measured using a differential pressure measuring device. This can be achieved with conventional differential pressure transmitters like the OPTIBAR DP 7060. As a solution for very high tanks (> 10m) a so called “electronic dp measurement” is possible, which offers a cost effective solution compared to conventional pressure transmitters. The Coriolis mass flowmeter in a single straight tube design is ideal for mass and volume flow measurement. EGM™ technology by KROHNE (Entrained Gas Management) was developed for OPTIMASS mass flowmeters to overcome problems caused by air or gas entrainments in a liquid. Powerful control algorithms allow the flowmeter to maintain operation over a wide range of gas fractions and complex flow conditions. Electromagnetic flowmeters with high accuracy and extensive diagnostic functions are also particularly suitable for these demanding hygienic applications. Fast, precise hygienic temperature sensors are ideal for all the required temperature measurements.