Originally Posted by petep1980
After playing with some numbers it dawned on me boil off should be measured in volume and not percentage.
Beersmith has 9%, and I'm assuming that's for 10-gallon batches, so I changed it for
18% for 5 gallon batchs and 36% for 2.5 gallon batches. That math looks better.
I noticed that in Beersmith it has a %, but you're correct- it should be the volume and not a percentage. If you're using the same pot in the same climate, you'll boil off the same volume no matter what the batch size.