Cool Brewing fermentation temperature controlling bag Controlling the temperature of actively fermenting wort has a major impact on the flavour of the finished beer. Fermenting above the desired temperature range can produce fruity off-flavours, esters and harsh fusel alcohols. The typical recommended ale fermentation ranges are 18-24 °C. It is not an easy task keeping an actively fermenting beer this temperature in a warm room. Add in the fact that active fermentation can raise the temperature 10-15 °C for a typical 20 litre batch! You can keep your Cool Brewing bag cold just as you would keep any cooler cold. Just add ice packs or anything cold to keep reach and keep the desired temperature. A great method is to use plastic bottles of ice. This way you can just refreeze them once they thaw and there is no mess. They also last much longer than ice packs. Easily lower the temperature by using frozen water bottles.
