The brewing process is energy-intensive in the Brewhouse where mashing and wort boiling are the main consuming processes. During the mashing process the malted barley is mashed with hot water for a period to allow the enzymes to break down starch and proteins. Once the wort is separated from the brewers grain by filtration, it is boiled for 1 – 1.5 hours in the wort kettle with hops or hop extracts. The rate of wort evaporation during boiling is 5-8% of the casting volume per hour.
The boiling stage has particular importance for the beer quality because in this operation the wort is sterilised, the malt enzymes are inactivated, the hops are added to the wort and the undesirable aromas and flavouring compounds are evaporated.
Traditional wort boiling requires high total evaporation (8-12%) to produce enough turbulence in the boil for a homogeneous wort heat transfer and guarantee the stripping of undesirable volatile substances. the two following techniques, which can be implemented at the same installation is the focus of this best practice:
- The recovery of heat from boiling vapour condensate and
- Reduction of total evaporation in boiling.