BIAB Questions

Hey everyone! I am new here, been lurking for a while, and am about to brew my first batch of beer! I have been doing a lot of research around here and other forums and just have a few things I am confused about that I need help on.

1) How to scale a recipe: I think I’m going to do 3 gallon batches for my first few brews so I can do a full volume mash (just got a 7.5 gallon aluminum brew kettle). I read that I just multiply all the ingredients by .6 to scale down from a 5 gallon batch, just want to make sure this is true for full volume BIAB. Also, do I need to scale the amount of yeast used?
2) How much water to use: How should I go about determining the amount of water to use for a full volume mash? I know a lot of people said to use beersmith or brew365 to calculate the mash volume, but I don’t know how to go about this for BIAB. And after the mash is complete, should I do any kind of dunk sparge, squeeze as much liquid out of the bag as I can and add it back into the kettle for the boil, or should I just let it drain and that’s it?
3) Adjusting recipes for BIAB: In the future, if I decide to do a 5 gallon batch with a sparge or addition of water to bring volume up after mash (since my kettle won’t be large enough to do a full volume mash), would I have to adjust the grain bill for the recipes? I read somewhere that with BIAB the amount of grain should be increased.. I guess I’m just confused about how to adjust recipes for BIAB.
4) How much water to use for non-full volume mash brews: Again, if I do 5 gallon batches, how would I go about determining this, along with the amount of sparge water? Is it any different than the calculated “mash/sparge water needed” done by brew364, for example?

Thanks so much for your help in advance, I really think this is a great place and I hope to be able to contribute in the future once I get comfortable brewing!

Welcome to brewing! I just finished my first BIAB the other day, I usually do all grain but only wanted a 3g batch for this one and my mash run was a little big for this.. the best advise for all of your questions to be answered on the cheap is get on the computer and download brew target. Its completely free and you can put a 5g batch into it then use the scale function under the tools tab at the top of the page and it will scale it down for you and calculate all of the mash and sparge water for you. If doing biab set it on all grain ideal under the equipment tab then put it in and scale it down. You'll have to play around with it a bit to figure it out but its a great all around piece of software and its free!! Good luck! And enjoy

Ok great, thank you so much! I just downloaded it and started playing around with it. So since I'm doing a full volume mash, I would just use the same amount of water as "calculated boil size" plus the amount of water that would be absorbed by the amount of grain? Or would I just use the "conversion amount" and "final batch sparge" (found under the "Mash" tab) and add them together? Thanks for your help, I really appreciate it.

I haven't tried any brewing software so I can't really answer your other questions but re: #3 the answer is "It depends". Most recipes are for 75% efficiency. Most BIAB brewers don't have a problem hitting that, but there are a lot of factors that could make you be over or under that. Of those, I think the crush of your grain is the most important.

Also, some squeeze the bag. Some don't.
I am in the "squeeze the hell out of it" camp.

bleme said:

I haven't tried any brewing software so I can't really answer your other questions but re: #3 the answer is "It depends". Most recipes are for 75% efficiency. Most BIAB brewers don't have a problem hitting that, but there are a lot of factors that could make you be over or under that. Of those, I think the crush of your grain is the most important.

Also, some squeeze the bag. Some don't.
I am in the "squeeze the hell out of it" camp.

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I'm a squeezer

Definitely squeeze if you want efficiency, there's a lot of wort stuck in there.

+1 to brew target or other software. Brewers friend is good too. It is online based. I bought brewsmith and I like it quite a bit. Also, you could go over to BIABinfo. They are pretty helpful and have a nice spreadsheet based calculator to help scale/design recipes.

I squeeze like there is no tomorrow.

1. Yes, just multiply by 0.3. I'm guessing you are relatively new, so you probably don't know your normal efficiency. No problem, assume 75% or so, and if you are a little off it doesn't really matter. If you happened to know, you could use that knowledge to hit your gravity targets.

As far as yeast, there really is no scaling. Or rather, you scale for every recipe based on a calculator. I like yeastcalc.com, but there are others. Use a calculator with your batch size and projected OG to determine what you need.

2. After getting your recipe figured out, multiply the lbs of grain by 1.25-1.5. That will give you the amount of water to use (in qts). So a recipe calling for 10lbs of grain would need 12.5-15qts or water (3.125-3.75gallons). I have heard that BIAB is ok with more water than this, whereas "standard" mash is more sensitive.

When you are nearly done with the mash, heat up some sparge water and either dunk your bag in it, or put the bag in a colander above your boil pot and pour the spare water over it.

And I'm a squeezer.

3. I don't adjust the amount of grain used when I do BIAB. Again, this is where efficiency comes into play (see #1 above).

4. I don't know what you mean when you say full volume mash or non-full volume mash. Mashing requires a somewhat specific amount of water compared to grain. Roughly 1.25-1.5 qts/lb. As I mentioned above, I have heard that BIAB is more forgiving of extra water, but I haven't done any experiments. I have used the ratio I just mentioned with good results.

As far as determining how much water to use, follow that ratio. Then sparge with enough water to get to your boil volume. If you want to do a full boil (not add top off water at the end), you will need to determine a boil off rate. If you boil off a gallon of water per hour, you will need to start with 6 gallons to get to 5 at the end of an hour long boil.

One thing to consider with a full boil is the amount of energy it takes to change the temperature of water. It has an extremely high specific heat (lots of energy required to change temperature). So you not only need a way to boil 6 gallons (unlikely unless you have a kick ass stove or a turkey fryer), you need to be able to cool it (without a chiller of some sort, you'll be waiting overnight in a tub of ice water).

Some say full boils are better. I'm certainly not arguing, but I love adding frozen sanitized water to cool in a hurry.

guitargeek said:

Ok great, thank you so much! I just downloaded it and started playing around with it. So since I'm doing a full volume mash, I would just use the same amount of water as "calculated boil size" plus the amount of water that would be absorbed by the amount of grain? Or would I just use the "conversion amount" and "final batch sparge" (found under the "Mash" tab) and add them together? Thanks for your help, I really appreciate it.

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Well actually once you put in the recipe, scale it down..then down at the midlow page where the tabs are Fermentables,hops,misc,yeast,mash..click on the "mash tab" hit the plus sign to add a step..fill that out to where you want your temps..time..ect,,, then once you get the first step in and finished, hit the mash Whiz tab over there on the bottom right and it will calculate your volumes,temps,everything. I dont know how more experienced BIAB'ers do it but for my go at it I mashed in, hit my temp and held for 90 mins(per recipe) then added the sparge water temp and amount given to me by the software in on top of my mash water, stirred the crap out of it to get all the sugars disolved (about 10 mins) then pulled the bag out and set a collander on top of the pot,set the bag in it and let it drain for about 15 mins or so...I got crazy efficiency, like 78% or something but I think it had alot to do with the grist.

I've done about 10 batches using BIAB with a 7.5 gallon kettle. I've been able to mash up to 12 lbs of grain with this kettle. Each time I start with 5.5 gallons of water. I've played around with mashing times, dunk sparging, squeezing the bag, and mashing out without seeing much of a difference in efficiency. A longer mash seems to help a little bit. I've ranged between 75% and 80% efficiency. If your recipe has a SG below 1.060, you can absolutely do all-grain 5 gallon batches in a 7.5 gallon kettle.

The recipe calculator that I love and recommend is on tastybrew.com. It's pretty similar to brew360.

Wow, thank you all for the great information. I definitely understand the process a lot more. I have a burner (pot and burner from turkey fryer), and am about to make a wort chiller tomorrow, and will probably brew either Saturday or Sunday. Now it's just a matter of finding a recipe for my first brew, probably a simple pale ale or brown ale or something along those lines. I'll let you all know how my first brew goes, I'm getting excited! Thanks again for all the great responses and info, it's much appreciated.

freisste said:

4. I don't know what you mean when you say full volume mash or non-full volume mash. Mashing requires a somewhat specific amount of water compared to grain. Roughly 1.25-1.5 qts/lb. As I mentioned above, I have heard that BIAB is more forgiving of extra water, but I haven't done any experiments. I have used the ratio I just mentioned with good results.

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Curious if you want to clarify your statement here?

I mash in usually with anywhere from 7-8 gallons of water depending on grain size and boil time. I am given the impression you are mashing in with less? Seems to me you are complicating the simplifcation of BIAB...

Yes sorry, forgot about that. I thought that a full volume mash was where you mash with the total amount of water you will use for the entire process, so the mash water along with the water you would normally use for sparging. So you would mash, then drain the grain bag, and then boil directly after, and end up with your target batch volume. Not trying to complicate anything, I just was confused, as I read so many different methods of BIAB. But now I understand that I can just mash with the usual amount of water, then squeeze the bag, then add the sparge water, mix, and then boil. Thanks for your willingness to help.

suprat78 said:

Curious if you want to clarify your statement here?

I mash in usually with anywhere from 7-8 gallons of water depending on grain size and boil time. I am given the impression you are mashing in with less? Seems to me you are complicating the simplifcation of BIAB...

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Not sure what you want clarified... I don't want to sounds like a jerk, but I am confused.

Yes, I mash in with less water than you. Unless your 7-8 gallons of water matches up with 20-25 lbs of grain.

How does water to grain ratio make anything more complicated? Maybe that I sparge? Definitely easier to not sparge, but I like my efficiency.

Let me know if I'm not answering your question.

guitargeek said:

Yes sorry, forgot about that. I thought that a full volume mash was where you mash with the total amount of water you will use for the entire process, so the mash water along with the water you would normally use for sparging. So you would mash, then drain the grain bag, and then boil directly after, and end up with your target batch volume. Not trying to complicate anything, I just was confused, as I read so many different methods of BIAB. But now I understand that I can just mash with the usual amount of water, then squeeze the bag, then add the sparge water, mix, and then boil. Thanks for your willingness to help.

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Full volume mash could very well be a common brewing term. I just haven't heard it. I assumed you were confusing full volume boil, just wanted to make sure we were on the same page.

Just finished brewing my first batch! A 5 gallon batch of an Amber Ale. Brewing process went smoothly (except for breaking a collander trying to squeeze the last bit of wort out of the bag). I ended up with a bit more than 6 gallons, I think due to the boil-off rate I accounted for being too high. Anyway, thanks for the help guys I learned a lot just through this thread. Now it's time to learn how to bottle, and to pray that I didn't screw anything up! I can't imagine anything worse than waiting a month to find out your beer is crappy haha