OG Limits of BIAB?

[petrolSpice]

When BIAB brewing, what would you say is the upper limit of OG I should try to achieve with grains only? For a 5 gal batch, I'm assuming that mashing 10lb of grain is a much different story than trying to mash 15-20lb. It seems like many people prefer to add extract to achieve a higher OG.

At what point should I add extract instead of trying to mash more grain?

Volume should not be an issue, I have an 11 gal kettle that I plan to use for mashing.

 

[TopherM]

There is no upper limit. You can mash as much as your pot can hold, assuming you can properly lift and drain the bag. When you hear people talk about BIAB having "limits," they are usually saying it is unreasonable to lift and drain XX lbs of grain once it gets too heavy.

There are commercial BIAB type systems now that produce several barrels of beer with hundreds of lbs of grain where the bag is lifted by a pulley system.

 

[MaxStout]

I think you would only be limited by the size of your kettle, and there will be a limit even with your 11 gallon BK. Many people do 5-gal BIAB with 20-25lb grain bills. There are some online calculators to determine what your upper limit would be.

Of course, you could hold back a few gallons of water from the mash to make it fit, then pour-over sparge after the grain bag is lifted out.

 

[KIAKillerXJ]

Yup, what everyone else says. Really limited by the size of your equipment and what you feel comfortable dealing with.

 

[laserghost]

Yeah, the original BIAB method recommends using a pulley to hang the bag over the kettle while it drains. I have a 12.5 gallon kettle and have done a 1.080 IIPA (1.5 lbs corn sugar added to boil) that was at my kettle's capacity with a full volume mash with ~ 17 lbs of grain. Lifting the bag without a pulley is hard.

Another thing you could do is mash, pull the bag, and then heat it back up to strike using that wort for a second mash. Would certainly be easier to just add some extract though.

 

[petrolSpice]

Perhaps I was under the impression that the more you try to mash the less ideal the water chemistry becomes, such as pH and gravity's effect on the conversion process? Or am I overthinking it?

If kettle volume is too small, couldn't you just use less water for the mash? What are the lower and upper limits are volume of water per lb of grain?

 

[laserghost]

The more water you start withholding from the mash due to lack of capacity, the more your efficiency begins to drop so you would need to compensate by adding more grain, but you are already at kettle capacity.

The double wort technique is an old method for making bigger brews, but adding extract would be easier.


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[seefish]

I am not sure about the water chemistry but you will most likely see a large drop in efficiency of the mash, probably having to do with the grist ratio. I range from about 70% for 1.050 to probably less than 60% efficiency for high gravity. I use a 10 gal kettle to mash and had to use a decent amount of dme to get to a gravity of 1.100. Of course, if you don't want to use extract you could always make a smaller batch.

 

[TopherM]

Here's some real numbers:

I did 5.0 gallon 1.09 OG BIAB Baltic Porter last Saturday with 78% efficiency with full water volume (7.2 gallons) and 13.5 lbs grain in a 11 gallon pot. I recirculate during my mash and double mill my grain.

I've only been recirculating my last few batches, but even prior to recirculating, I was routinely around 72-74% efficiency.

I hear all the time that BIAB suffers from low efficiency at higher OGs, but I have yet to see any good science or reasonable explanation.

The only variable in a BIAB mash that is different than a traditional mash would be the grist ratio; where BIAB typically uses full volume water while traditional typically uses the benchmark 1.25 qt water per 1 lb grain. I still have not seen any detriment to my personal efficiency, but if you are doing BIAB and think this affects you, just do a 1.25 qt/lb grain mash, then do a BIAB sparge with the remaining water volume at 170F, pouring that water through the grains or dunking the bag in that water, which negates the water volume variable and makes your BIAB mash/mashout EXACTLY THE SAME as the traditional.

 

[laserghost]

I'll add to this. I single mill my grains, mash 90 minutes, stirring every 20 minutes and I am always in the range of 76–81%

I have a wide kettle with 1.42 gal/hour evaporation. Lots of the time I'm doing a 90 minute boil. That means I'm starting with more water in the mash which I believe increases the efficiency due to a higher water to grist ratio.


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[petrolSpice]

Here's some real numbers:

I did 5.0 gallon 1.09 OG BIAB Baltic Porter last Saturday with 78% efficiency with full water volume (7.2 gallons) and 13.5 lbs grain in a 11 gallon pot. I recirculate during my mash and double mill my grain.

When I plug your numbers into Brewer's friend I get 1.078 OG (assuming pale 2-row).

 

[TopherM]

I was working off memory, but I'll double check my BeerSmith #s when I get home. Obviously, a Baltic Porter wasn't all two-row, but you're right, I must have been closer to 1.08 than 1.09.

 

[petrolSpice]

I was working off memory, but I'll double check my BeerSmith #s when I get home. Obviously, a Baltic Porter wasn't all two-row, but you're right, I must have been closer to 1.08 than 1.09.

Ok I was just curious. Even after 6 batches I still feel really new to this

 

[dobe12]

Ok I was just curious. Even after 6 batches I still feel really new to this

I'm at batch 100 (hopefully this weekend) and I still feel new at this

Like others said, there's no magic number. You're only limited by your kettle size and how much wet grain you can lift. I mash in a 10gal pot on the thinner side around 1.5 - 2.0qt/lb. I then sparge in a second 7.5gal pot to try to get close to equal runnings from both. For an average grist of 10-12lbs my efficiency is 80-85%. Smaller grist and I'm 85+%. For larger grists, my efficiency does drop. I've done a few 18lb batches and am just over 70%. Still very acceptable to me. I like getting high efficiency, but consistency and knowing what my OG will be is even more important.

Remember mashing thicker around 1-1.25qt/lb is suppose to help convert quicker, but won't convert as much. Mashing thinner will convert slower, but will convert more. At least that's what I've read. I haven't specifically tested the theory, but my decreased efficiency with larger mashes would point to the theory being true since I have to cut the water ratio down for bigger batches.

 

[KIAKillerXJ]

I've done 1.110 batches, both 5 and 10 gallons, in a 15 gal keggle, and a 25 gal kettle. All grain. the 5 gal was very heavy with the grain qty, and for the 10 gal had to use a electric winch on my Jeep to pull it up with a pulley.

 

[craigmw]

I'm at batch 100 (hopefully this weekend) and I still feel new at this

Like others said, there's no magic number. You're only limited by your kettle size and how much wet grain you can lift. I mash in a 10gal pot on the thinner side around 1.5 - 2.0qt/lb. I then sparge in a second 7.5gal pot to try to get close to equal runnings from both. For an average grist of 10-12lbs my efficiency is 80-85%. Smaller grist and I'm 85+%. For larger grists, my efficiency does drop. I've done a few 18lb batches and am just over 70%. Still very acceptable to me. I like getting high efficiency, but consistency and knowing what my OG will be is even more important.

Remember mashing thicker around 1-1.25qt/lb is suppose to help convert quicker, but won't convert as much. Mashing thinner will convert slower, but will convert more. At least that's what I've read. I haven't specifically tested the theory, but my decreased efficiency with larger mashes would point to the theory being true since I have to cut the water ratio down for bigger batches.

I think this is generally correct, and given this, it is reasonable to think that a typical BIAB would thus be a better approach for yielding high gravity worts than a traditional approach due to the thin mash. However, the downside to thin mashes is the denaturation of the amylases. I'm not sure I fully understand why this would be, but that's what has been claimed. I've gone as high as 1.084 with ease on my BIAB rig, but I'd like to try a higher gravity at some point just to find that limit.

 

[RM-MN]

I'm at batch 100 (hopefully this weekend) and I still feel new at this

Like others said, there's no magic number. You're only limited by your kettle size and how much wet grain you can lift. I mash in a 10gal pot on the thinner side around 1.5 - 2.0qt/lb. I then sparge in a second 7.5gal pot to try to get close to equal runnings from both. For an average grist of 10-12lbs my efficiency is 80-85%. Smaller grist and I'm 85+%. For larger grists, my efficiency does drop. I've done a few 18lb batches and am just over 70%. Still very acceptable to me. I like getting high efficiency, but consistency and knowing what my OG will be is even more important.

Remember mashing thicker around 1-1.25qt/lb is suppose to help convert quicker, but won't convert as much. Mashing thinner will convert slower, but will convert more. At least that's what I've read. I haven't specifically tested the theory, but my decreased efficiency with larger mashes would point to the theory being true since I have to cut the water ratio down for bigger batches.

I've played around a bit with iodine to see how quickly conversion occurs. I don't mash in quite full volume because of equipment limitation but pretty close so I'm mashing in about 2.3 qt/lb. I had heard that conversion could be pretty quick but no numbers were mentioned so I experimented by taking a sample right at dough in and planned to sample every 5 minutes until the iodine/wort mixture quit changing color. As expected, at dough in the iodine/wort was dark blue which showed that there was starch. At 7 minutes there was no longer any color change.

Since I had missed my 5 minute sample I did this again with another batch of beer only this time, knowing that I showed no starch at 7 minutes, I set up several drops of iodine on a white plate so I could get several samples quickly and started taking samples every minute after dough in. The iodine/wort samples quit changing color between the 2 minute sample and the 3 minute sample. Note that I mill my grains very fine so if your timeline doesn't match mine if could be from using grains that are coarser.

I've quit doing 60 minute mashes, I've even quit doing 30 minute mashes, and instead have started doing 10 minute mashes. From what I can tell, my beers haven't suffered a bit from shortening the mash period but I have less temperature loss.

 

[laserghost]

interesting thread over here about iodine tests.

seems like if you want the most extraction you'll mash longer. RM-MN, have you played with that at all in your tests?

 

[RM-MN]

interesting thread over here about iodine tests.

seems like if you want the most extraction you'll mash longer. RM-MN, have you played with that at all in your tests?

I have not. When I get 85% efficiency with a 10 minute mash and 85% efficiency with a 30 minute mash that would seem to equate to equal extraction. I won't have time to try these experiments again until October but if someone else wants to try I'd be happy to hear of the results.

 

[Fat_Maul]

I think you would only be limited by the size of your kettle, and there will be a limit even with your 11 gallon BK. Many people do 5-gal BIAB with 20-25lb grain bills. There are some online calculators to determine what your upper limit would be.

Of course, you could hold back a few gallons of water from the mash to make it fit, then pour-over sparge after the grain bag is lifted out.

Max, I looked at that calculator and it only tells you how much strike water to use, not how large of a vessel you need. You need to know how much move volume the grain will occupy. I really wish there was an all inclusive biab calculator that worked for both sparge and no-sparge methods that takes boil kettle size into account. If there is one, I haven't found it yet. I was playing with a trial version of beersmith and it's not really geared for the weekend warrior. I just want to know

• Is my kettle big enough to do a no-sparge mash?
• How much water to mash with and if it doesn't fit, how much I need to add post-mash (does this mess up the pH?)
• What should my pre-boil gravity be?
• If my pre-boil gravity was off, how can I adjust (squeeze or add water) and what do I have to do to compensate during the boil?

Sometimes I feel like you should target your post-boil volume for the mash so you can see if your gravity is correct more easily then you just add whatever amount of water you will be boiling off and you're done. Let me know if I am over-complicating this but this is where I struggle the most when trying to make sure I boil for the proper length of time while hitting the correct OG.

 

[laserghost]

@Fat_Maul the wise folks who invented BIAB have created a calculator that does everything you mentioned and more. It's in the form of an excel spreadsheet but it's extremely accurate and easy to use. Getting up and running on their site is a little weird but worth it.

Check out the BIABacus http://www.biabrewer.info/viewtopic.php?t=1869 – currently in pre release stage you can get it by signing up on their site. It looks kind of intimidating at first but if you crack a beer and spend 20 minutes with it you'll be gold and the guys on that forum are super helpful.


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[TexasWine]

Max, I looked at that calculator and it only tells you how much strike water to use, not how large of a vessel you need. You need to know how much move volume the grain will occupy.

This calculator will give you a very quick answer to your question. Loom at the bottom for Total Mash Volume.

http://biabcalculator.com/index.htm

 

[Conestoga]

@Fat_Maul the wise folks who invented BIAB have created a calculator that does everything you mentioned and more. It's in the form of an excel spreadsheet but it's extremely accurate and easy to use. Getting up and running on their site is a little weird but worth it.

Check out the BIABacus http://www.biabrewer.info/viewtopic.php?t=1869 – currently in pre release stage you can get it by signing up on their site. It looks kind of intimidating at first but if you crack a beer and spend 20 minutes with it you'll be gold and the guys on that forum are super helpful.


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x2

The BIABacus is pretty amazing. I've brewed 10 times with it and it's spot on every single time.

This calculator will give you a very quick answer to your question. Loom at the bottom for Total Mash Volume.

http://biabcalculator.com/index.htm

I just typed in data from a recent completed brew, and it's way off from my actuals. What a terrible calculator.

 

[kenny_d]

x2

The BIABacus is pretty amazing. I've brewed 10 times with it and it's spot on every single time.



I just typed in data from a recent completed brew, and it's way off from my actuals. What a terrible calculator.

BIAB Brewer and I've used "The Calculator" or "BIABacus" for the last 4 brews and I always hit my numbers. This calculator is amazing and every BIAB Brewer should have it IMO.

 

[laserghost]

@Conestoga hey for some reason your reply looks like I was suggesting that terrible calculator.

BIAB "The Calculator" is the original spreadsheet and very accurate as well. Looking forward to the BIABacus official release!


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[Conestoga]

@Conestoga hey for some reason your reply looks like I was suggesting that terrible calculator.

Not sure why that would be, looks fine on the full site. Perhaps whatever app you are viewing through doesn't handle multi-quote very well.

 

[Fat_Maul]

Thanks. The Biabacus only lets you input recipes in metric and that seems like a pain to convert everything especially when just playing around with recipes. Do you know if there are plans to allow for standard inputs or a modded version of the spreadsheet that allows it?

 

[kenny_d]

Thanks. The Biabacus only lets you input recipes in metric and that seems like a pain to convert everything especially when just playing around with recipes. Do you know if there are plans to allow for standard inputs or a modded version of the spreadsheet that allows it?

Sent a pm.

 

[laserghost]

I use percentages for the grain bill and then rough in the volumes and it shows you the gallons or ounces right next to it. There is another tab on the spreadsheet that does quick conversions that I use when I want the exact amount.


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