I plan on doing my first biab this weekend a 3 gallon batch.Northern brewer doesnt seem to carry to many 3 gallon kits,so my question is can you brew a allgrain kit as biab if so how do you adjust the kit for 3 gallons?

Easy – just use 3/5 as much of all the ingredients in 3/5 the volume. Works fine.

+1 to the above. Or if you have a big enough kettle, just brew a 5 gallon BIAB. Although if you’re posting this I assume you’re confined to a smaller kettle.

Another thing I’ve done in the past is partial boil BIAB. By that I mean I made an 8 gallon batch, but only BIABed and boiled for 5 gallons, then when I transferred to the fermenters I topped up to 8 gallons. You’ll lose hop utilization and possibly alter caramelization characteristics, but the few times I’ve done this I’ve had good results, and I’ve never had any complaints from my beer-hungry-never-reciprocating-friends. The one side-effect I’ve noticed on one of these batches is that I had a few gushers after about 6 months of aging, but I think that might have been a bottle cleansing issue since it didn’t seem to be the whole batch.

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I’ll take a recipe for, let’s say, 5 gallons. Divide the 5 by 3. That gives me a sum of 1.66. I then use that divisor to figure out the amount of grain and hops I need to convert the recipe down for 3 gallons. i.e. - if the recipe calls for 6 pound of pale malt I divide the 6lb by 1.66 and come up with 3.61lb for my three gallon batch.

That’s one way to do it… Personally I’d multiply by 0.6. The math is easier. Or just cut everything in half but round up a little. It’s all good.

So if I have a 12 pound grain bill I would cut that if half for a 3 gallon batch?

[quote=“hophead05”]So if I have a 12 pound grain bill I would cut that if half for a 3 gallon batch?[/quote]You’d likely end up a little low on OG if you do that - instead, multiply by 0.6 and use 7.2 lbs.

Sounds good thanks man!

I take any ingredient from the recipe I’m using and multiply it by 3 (for a three gallon BIAB batch) and divide that number by the number of gallons from the original recipe, usually 5 gallons. For instance, if a recipe calls for 8 lbs of maris otter, I multiply 8x3=24 and then 24/5=4.8lbs of maris otter. Remember to do that for EVERY recipe ingredient, including hops.

When brewing I use about 5.5 gals of water total: I heat 3-3.5 gals for my mash water, and as I’m holding that for an hour, I heat another 2-2.5 gals. of water to 170 and to do a mash out. I know that most people don’t do this with biab, but I have two boil kettles and and can afford to do it. I’ve done about 5 batches, and I love BIAB 3 gallon batches because I can do a greater variety of beers. Using 5.5 gals. of water comes out right around 3 gals after boil.

hekkubus, I liked math in school. But I don’t want to do double the calculations. :oops:

Another option is to use brewing software that has a volume conversion option.

You can brew any NB all grain kit as BIAB, not just the 3 gallon ones they advertise as BIAB kits. The key is having a kettle big enough for a full 5 gallon BIAB. I have the 10 gallon Tall Boy and it’s about as small as I’d want to go for a 5 gallon BIAB. Any grain bill over 13-14 lbs is pretty close to maxing my kettle out once you try to fit the grain and 8-9 gallons of water in there. Of course, if your kettle isn’t big enough, you could fit as much as you can and then do a quick and dirty sparge to make up for the remaining volume, but that kind of defeats the purpose of BIAB.