Dismiss Notice
Microbrew Invitational
Join us June 3 + 4 in Boston and help us drink 300+ beers, ciders, kombuchas, meads, sakes and more!

TICKETS: beeradvocate.com/micro/

BIAB Water Calculator

Discussion in 'Homebrewing' started by hopsandmalt, Jan 5, 2013.

  1. hopsandmalt

    hopsandmalt Savant (400) Michigan Dec 14, 2006 Verified

    I'm brewing my first BIAB attempt this weekend and I was wondering if anyone has a simple calculation for water volume (or can point me toward a tried & true online calculator).

    It is a 3 gallon batch with 5.5 lbs of grain.
  2. Assuming no-sparge BIAB:
    Total water volume = final batch size + trub/hop loss + boil off loss + grain absorption

    I've seen some recommendations in other forums about estimating a range of 0.06 to 0.10 gallons per pound of grains for the grain absorption, depending on how much you plan on squeezing the grain bag after the mash. So for your batch, a grain absorption estimate could be 0.08 gal/lb X 5.5 lb = 0.44 gallons. (Used 0.08 in example as a middle of range value). So, about a half gallon there.

    Unfortunately, there are a couple of variables unique to your own brewing setup, so some trial and error is involved. You have to best-guess boil off loss, which is unique to your kettle dimensions and how high you crank the heat. Even weather/wind can affect it if you brew outside. Hopefully you have an idea of this value from previous batches of extract or partial mash brews. I normally lose about a gallon during a 60 min boil on my propane burner for 5 gallon batches. Trub loss also varies among batches, so you have to guess this also, or just ignore it (in other words, decide if you want 3 gallons of actual finished beer to drink after trub settles, or simply 3 gallons into the fermenter post-boil).

    Take good notes and volume measurements during your first few BIAB batches, then you should be able to nail a good starting water volume every time for your setup.
  3. jmich24

    jmich24 Advocate (545) Michigan Jan 28, 2010 Verified

  4. koopa

    koopa Champion (870) New Jersey Apr 20, 2008 Beer Trader

    I used to "Squeeze the bag" to reclaim as much wort as possible when I was no sparge BIAB brewing and I would leave about 0.05 - 0.07 gallons per pound of grain behind on average.
  5. hopsandmalt

    hopsandmalt Savant (400) Michigan Dec 14, 2006 Verified

    Cool, I have run across this one amongst others when searching for a calculator and I just wanted someone who had used one with good results to weigh in on it's reliability.

    As far as the rest is concerned, I don't think I'll be doing a ton of BIAB in the future so I'm not too worried about perfecting the process. I'm an all grain brewer from way back. I'm just looking for an easy way to make a giant starter for a big ol' bock I'm going to brew in a few weeks.