Boil-off (evaporation)
Term from the Brauwerkstatt brewing glossary, category “Brewing and equipment”.
Explanation
Water that evaporates during the boil: usually 2–4 L (about 0.53–1.1 gal) per hour on all-in-one systems, 4–6 L (about 1.1–1.6 gal) in an open pot. Measure the volume once before and after the boil. Then you know your own value and hit the original gravity more reliably.
Work it out yourself
Water volume calculator – How much water do you need on brew day, and how hot does it have to be? The calculator tells you step by step.
Frequently asked questions
How much water do I need?
It depends on batch size, amount of malt, boil time and your system. The water volume calculator under “Calculators” works out mash and sparge water and tells you how hot the water has to be. After your first brew, enter the evaporation and losses of your own system under the fine settings.