Determing pre-boil volume...

[Sordfish]

Hi all,

Well my first batch is fermenting away and I'm already thinking about my next batch.

Due to space limitations I would like this next batch to be 2.5 to 3 gallons. I know that some volume will be lost during the boiling process, so I need to start off with more than 2.5 to 3 gallons.
My question is: how do you determine the pre-boil volume so that you are at or near your planned final volume after the boil?
Is there a rule of thumb or formula that is used, or do I need to use some kind of brewing software?

Thanks!

 

[Jayhem]

It depends on your elevation, humidity, air temperature, etc. Brewing software like Beersmith2 will help you. I have found that during a 60 min boil it's around 1 gallon lost to trub/evaporation when boiling 2.5-3.5 gallons.

 

[bleme]

BeerSmith can get you close, but there are too many variables (the size of your pot, the heat of your burners, type of hops and grains used, etc.) to figure this exactly.

I would use your first batch to make a best-guess, cut that by a little, and have some extra water on the side to top off after boil. You can boil that water or use a bottled water.