I recently brewed a batch of beer that had about a gallon and a half of leftover wort with an OG of around .055. I thought that sounded like a good amount to make a test batch with some old hops and yeast I had laying around.
Two birds with one stone, sounds like a good idea. Wrong!!
So I decided to do a boil in a small pot while I was doing my main batch. By the time I got done with the batches I realized my main batch was about a third of a gallon short of the final wort I calculated! My boiloff was higher than expected.
Who knows if I miscalculated or little fairies were dipping straws in my batch when I wasn’t looking the problem was I needed to use sanitized water when I could have used the delicious leftover wort. Which at this point had a completely different hop in it than what I originally wanted.
Moral of the story. Don’t get greedy. Stick to one batch and make sure you can make it the best possible.
Boiloff Calculator: http://www.brewersfriend.com/dilution-and-boiloff-gravity-calculator/
Photo: Yea, that’s some chicken about to get cooked sitting beside that brew.