BIAB Question

[torbanac]

That calculator uses the standard volume of water for an all grain mash that is assuming a sparge later to make up the volume. I don't think there's a calculator for BIAB. You have to work it backwards. Start out with your finished batch volume and then add water for the boil off and then add water for the grain absorption to get the total water needed. That 1.25qt/1lb needs to change to about 2.3qt/1 lb for BIAB . Using that calculator it would be around 5.57 gallons in the pot. I would like to know it there is a set figure for BIAB with that calculator myself. Anyone?

 

[jgoette]

If you are doing full volume BIAB, your mash thickness wil be closer to 3 qt/lb. Depending on your batch size. I typically do 4 gal batches with about 7 lbs of grain. My mash thickness is usually 3.1qt/lb.

OK, so I used 3.1 qt/gal and 8.5 lb grain and it spit out 7.27 gal of space... Sound about right?

 

[djt17]

OK, so I used 3.1 qt/gal and 8.5 lb grain and it spit out 7.27 gal of space... Sound about right?

What is your batch size, what is your boil off rate, & what is your loss to grain absorbtion? With my system, I start with 5.5 gal water for 4 gal batches. If you are doing full volume BIAB, all this water needs to be figured in your mash thickness.

 

[jgoette]

I mean, I'm not real sure what my batch size is yet... that's what I'm trying to decide upon... I want to brew the most beer at once as possible...

I thought boil off rate was 1gal/hr and that grain absorption was like .12 gal/lb of grain

 

[flipfloptan]

You just need to take the plunge on your first batch. The computer programs are just geusstimates. Plus they are not programed for BIAB volume. A beersmith article says to use single infusion mash on their program for the best geuss on water volume.

http://www.beersmith.com/blog/2009/04/14/brew-in-a-bag-biab-all-grain-beer-brewing/

If you are way off during the process you will be able to fix with a longer boil or adding a little water.

You can figure out your boil rate by putting in 5 gallons and boiling for a 1/2 hour measure and multiply it by 2. Then just use the water for your brew day.

For example, if you take the Haus Ale recipe and reduce it by 60% to be able to do a 3 gallon boil. (A little more than a case of beer) you could do the following:

6.3 lbs of grain x.125 for absorption= 3/4 of a gallon
Assume your boil of rate is a gallon/hour
Batch size is 3 gallons.

You would end up with .75+1+3=4.75 gallons of water. That would fit nicely in your kettle.

I followed this line of math and thinking on my first BIAB and had about a quart to much water. I let it go because it would probably be absorbed in the fermenter.

Remember you will have beer at the end and know what your true numbers are next time.

 

[jgoette]

Good point...

I will finish putting together the equipment I need and will give this a whirl...

 

[wacko]

personally I think you could do a 5 gallon but it would be tight at boiltime

 

[jgoette]

Yea, I've read some other stuff saying that too...

it seems I would have to keep a spray bottle in one hand, and my other hand on the gas...

 

[AviatorTroy]

I try to mimic a normal mash schedule as much as possible with BIAB.

I do my conversion at about 1.5qt/lb so I'm heating about 3.75 gallons of water up to 165 or so so that with around a 10 lb grain bill you should hit 156-158.

you can do a "mash out" with BIAB. Keep grains in, turn heat on, once temp reaches 170-175 do a quick stir, or move bag up and down. Place bag over brew kettle on a grill to finish draining.

Yep, I do that too. Then raise the bag and drain for a few minutes while I'm heating up 3.5 gallons of sparge water to 170 in a seperate pot. Then I dunk the grain bag in the sparge water and stir for about 10 minutes, then drain again. When you hang your bag to drain, and then combine the sparge water and the "first runnings" you should be pretty darn close to 6 gallons or just a little over, which is good for a 60 minute boil in a 7.5 gallon BK.

 

[AviatorTroy]

^^^ Oh yea, and be careful with your grain bill, last time I did this I got 89% efficiancy!!! :rockin:

 

[jgoette]

hrm, 1.5qt/lb is a long ways away from 3.1qt/lb... whats up with that?

 

[torbanac]

He is adding a sparge. "few minutes while I'm heating up 3.5 gallons of sparge water to 170 in a seperate pot. " For Aussie style BIAB i would stick with the higher figure. Plan on a little longer mash (i do about 75 min) and then mash out for ten min at 170. If your preboil volume is a little high you can always just boil longer.