# BIAB Calculator

I have been using this one: http://biabcalculator.com/

Are there any better ones out there that you all would recommend? Brewing my first BIAB (5.5 gallon batch of Irish Red) and want to get my mash water volume correct.

I found this a while ago and just stuck with it.

http://www.rackers.org/calcs.shtml

It’s not specific to BIAB, which is how I brew, but BIAB is no different than a normal mash. I mean, it can be if you go full volume, no sparge, etc, but BIAB doesn’t need it’s own specific calculator. Mashing is mashing. You just need to learn and understand your system and it’s neuances.

Dobe, Thank you for posting that.

How can I determine my grain absorption rate? Should I leave it at the default? Assuming double crushing effects it? One of the calculators defaults to .125 the other to .045. That’s a difference of about a gallon or more.

[quote=“Scalded Dog”]Dobe, Thank you for posting that.

How can I determine my grain absorption rate? Should I leave it at the default? Assuming double crushing effects it?[/quote]

I usually see 1.25qt/lb (on calculators I mean), but with BIAB you can squeeze a little more out of the grain sack. I don’t go crazy trying to get every drop, but I do give it a little squeeze. I usually estimate at 1qt/lb loss. But really we’re talking about fractions of a qt/lb which IMO isn’t a big deal. You’ll need to brew a few batches and figure out what you end up with. Try 1qt/lb to start.

I find that my boil off rate is much less predictable. The weather can really make a big difference. I’ve had boil off rates of 15%/hr (warm, humid, summer day) up to 25%/hr (cold, dry, winter day). These are the numbers that continue to elude me.

EDIT: Typed those numbers out wrong. My bad. Corrected now.

Thanks Dobe…I’m ready and excited to brew my first BIAB…also brewing a batch of the BB Porter, that will be ready (hopefully) for Memorial Day.

If you have the ability, crush your grain a little finer than normal or double crush. The one major bonus of BIAB is you don’t have to worry about a fine crush. There are no stuck sparges with BIAB. You’ll get better efficiency. I can generally hit around 80% give or take 5% depending on the size of my grain bill.

Good luck! :cheers:

[quote=“Scalded Dog”]I have been using this one: http://biabcalculator.com/

Are there any better ones out there that you all would recommend? Brewing my first BIAB (5.5 gallon batch of Irish Red) and want to get my mash water volume correct.[/quote]

FWIW - I have been using this calculator and have probably 10 BIAB bacthes under my belt. I find it to be pretty accurate.