Planning on doing my first BIAB (first time all-grain as well) this weekend and just want to make sure what I'm doing makes sense. I'm looking to do a 2.5 gallon batch with 6 lbs of grain. To get to 2.5 post boil I think I need 3.5 pre-boil (1 g per hour). Also thinking grain absorption of .72g (.12 g per pound of grain. So need to put the bag into 4.25 gall of water. Also assuming .48 g (.08g per lb of grain) displacement, so I should just fit in my 5 gal pot. Also, is this what most people are doing, or are most people doing BIAB mashing into smaller volume (1.5 q per lb) and then adding water? Any advantage or disadvantage to either? I would think higher concentration of enzymes in smaller mash might be beneficial but also might limit efficiency (lower water to grain ratio leading to saturation). Any advice is much appreciated. Thanks.
I do 5 gal BIAB brews and mash with slightly less water and then "sparge" up to my desired pre-boil volume. Advantage is more room for large grain bills, possibly better efficiency, and control over pre-boil volume. Disadvantage is that it's an extra step (I think most BIABers do no-sparge), but it only adds a few extra minutes to my process. I also learned that the crush is very important to efficiency. I have my LHBS double-crush the grains (no worry about a stuck sparge) and I have been surprised at how consistent my efficiency has been.
Thanks would be impossible for me to do anything above 6% ABV or so without going your method in my current set-up. I did ask for double crush. Sparge 178ish? Any particular volume or % you sparge with? Sparge before squeezing the grains or squeeze sparge squeeze again?
Yeah, I do a double crush and then some for BIAB. Generally, I would just bring in a maltbill and they would crush it but I never was quite getting the efficiency I was looking for. Recently they have adopted a self serve policy on milling grains which is great......I can verify what I am getting and mill to my preference......it turns out that the LHBS was having theft issues when the sole employee was in the back crushing grain, ie "copper chillers were just walking out of here and we wouldn't catch it until inventory time".
For a big (~1.070) IPA with lots of kettle hops, I shoot for 6 gals post-boil, so about 7.3-7.5 gals pre-boil. I usually dough-in with 7.5 gals water and then pull the bag and place it on a grate on top of the kettle as it drains. I do squeeze a little by pressing on the bag with my big spoon. Once the draining slows I then "sparge" by slowly pouring about 1 gal of 175 degree water over the grains (I heat up about 2gal in a smaller pot) and press on the bag with the spoon to squeeze some more. I take the bag and grate off the kettle when I'm at the pre-boil vol. I've been happy with this for the last 15 brews or so, but (full disclosure) I don't enter comps!
I mash at about 1.75 qt/lb, then do a dunk sparge into hot 190-200 F water to improve efficiency. This obviously requires a second kettle. You can also use several regular pots on your stovetop if you don't have a second kettle, then dump the hot water into a bucket and do the dunking in there, whatever it takes to get you some dunk "sparge" water. Doing this along with a long boil, I have successfully made beers all the way up to an original gravity of 1.113 with efficiency in the 80s.
I basically do what buck89 does for my batches in that I need to add water after the mash because it all won't fit in my pot. So I pour (sparge) another gallon or two over my grain bag while it is resting on an oven grate on top of my pot. I'd point out that if you want 2.5 gal of finished beer, you probably need at least another .25 gal in your fermentor. Also, a brewing calculator will do the math for you to make sure it fits. I use vikeman's BrewCipher. Extremely helpful.
