I am going to start doing a BIAB. I was wondering is there any adjustments I need to make to my standard all grain recipe when doing a BIAB? I plan on doing a 5 gallon batch which is what I normally do for All Grain. Thanks
Adjustments are usually made only for water volume calculations:
- Full volume mash (or minimal sparge) vs. 50/50 in trad. AG
- Less grain absorption; 0.6-0.8 gal/lb vs. 0.11-0.13 for trad. AG
...and potentially a finer crush, depending on how fine it is already.
Otherwise grain, hops, all the usual stuff applies.
(And, wait for it... someone will chime in and tell you to adjust the recipe for lower efficiency. In general that is NOT true, but it's possible that you'll benefit from doing it the first time. Once you dial in BIAB, it will be equal to or better than your current efficiency.)
Use as fine of a crush as you can get, then adjust your efficiency to take that into account....on your next brew when you know the results. My first batch was based on a recipe that expected 70% efficiency but I got 80. After a few brew sessions with that high of efficiency, I started adjusting the recipe to take that into account. Since the crush is the main factor in efficiency, your results may vary from mine as I mill my grains very fine.
BIAB can be done exactly as you have done your batches in your mash tun. It can be done way differently if you want with full volume, no sparge, or a little less volume and a small sparge to gain efficiency and get to the preboil volume you want. It's still all grain but it just eliminates the mash tun cooler and false bottom/bazooka screen with a bag with such a large filter area that you can mill finer and not worry about getting a stuck mash or sparge.