BeerSmith Software > BeerSmith 2 Questions

Chaning Boil Time Does Not Change Est ABV


Bob Monkhouse:

I recently noticed that if I change the boil time in the recipe design, BS2 does not adjust the estimated ABV. So for example, a recipe with a boil time of 1 minute has the same estimated ABV as if the boil time were set to 500 minutes. Am I doing something wrong? It caught me out a couple of times! I should probably be using BS3 by now, but wanted to flag this as a potential bug.


If the "Use Boil Off as an Hourly Rate" box is checked in your equipment profile, changing the boil time increases the water volume to compensate for the additional boiloff and result in the same OG/ABV. BS3 does the same, as it should.

You are not doing anything wrong.  It is the way the program works.

Your final gravity is dictated in your equipment profile as the percentage of the fermentable sugars which make it to the fermenter.  So if you change the boil time, the program still calculates the same amount of sugars into the fermenter.   

When I want to change my boil time, I will note the mash efficiency in the original and then alter the boil time.  I then adjust the brew house efficiency to attain the same mash efficiency as I had previous to the change.  For relatively minor changes (60 minutes to 90 minutes) this will get me pretty close.  Larger changes in boil time will call for vastly greater amounts of mash and sparge volumes which will affect your mash efficiency to some extent.

Bob Monkhouse:
Awesome, thanks guys. I'd figured out that adjusting brew house efficiency was the key after I posted, but thanks for the confirmation.


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