Boil off?

petep1980 said:

I wasn't sure where to post this, so I posted it here since it affected my efficiency calcs.

I did a no mash out, no sparge brew yesterday, it was a half batch and I had about 3 gallons go into the boil. I swear out of the boil I was far less than 2 gallons. My OG into boil was 1.039 and out of it 1.060 if that tells you anything.

Beersmith has 9% boil off per 60 minutes.

I boiled off maybe 30%.

I'm confused.

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petep1980 said:

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.

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