First BIAB, low efficiency?

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mmills06

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So, tonight was my first time doing a BIAB batch with my new equipment. I have an 11 gallong Bayou Classic kettle with the SS basket which I put my bag in. I was doing an IPA recipe w/ 13 pounds of grain. I heated 7.5 gallons to 161 degrees and added in the grains and the temp dropped to 153 (target mash temp of 152). I constantly stirred the grain while pouring in with a 24" whisk. Mashed at 152-3 for 60 minutes, after 60 minutes temp was at 150. The preboil hydrometer meeting came out to 1.27 @ 151 degrees and 7.0 gallons, resulting in around 62% efficiency (1.042 adjusted, but target was like 1.058?). What did I do wrong? I ended up tossing in 1lb of DME during the boil to bring up my final OG to 1.061 (target 1.067), but still, how can I get my BIAB system to be up around 70-80% like most claims i read about?
 

BUCKNUTS

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So, tonight was my first time doing a BIAB batch with my new equipment. I have an 11 gallong Bayou Classic kettle with the SS basket which I put my bag in. I was doing an IPA recipe w/ 13 pounds of grain. I heated 7.5 gallons to 161 degrees and added in the grains and the temp dropped to 153 (target mash temp of 152). I constantly stirred the grain while pouring in with a 24" whisk. Mashed at 152-3 for 60 minutes, after 60 minutes temp was at 150. The preboil hydrometer meeting came out to 1.27 @ 151 degrees and 7.0 gallons, resulting in around 62% efficiency (1.042 adjusted, but target was like 1.058?). What did I do wrong? I ended up tossing in 1lb of DME during the boil to bring up my final OG to 1.061 (target 1.067), but still, how can I get my BIAB system to be up around 70-80% like most claims i read about?
I have done about 90 biab batches and my efficiency is 65-70% and I'm fine with that. you could increase the mash time and crush fine, very fine for biab as there are no issues with lautering. I have the same pot and I scrapped the basket early on as I got very different temp readings for the mash vs the liquid outside and under the basket which was a concern for me. I use a simple pulley system to drain the bag now.
 

MindenMan

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mmills06, I am confused... You state you started with 7.5 gallons of water added 13 pounds of grain and ended up with 7.0 gallons. The usual absorption rate of grain is around 1 pint a pound, so you should have been around 6 gallons pre boil, did I miss something?

Grain in pounds (13)* 0.12 = 1.56 gallons lost to grain, so if your pre boil volume was to be 7.5 gallons, you should have started with 9 gallons. That extra water would have probably helped your efficiency.
 

doug293cz

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First thing to try is to crush finer (I crush at 0.016" mill gap for BIAB, but many BIABers crush even finer), and/or extend your mash time. Your apparent grain absorption is about 0.04 gal/lb which is actually on the low side, so your low efficiency was not due to excess wort retained in the grain. So that leaves incomplete starch to sugar conversion as the likely culprit. Finer crush and longer mashes can both enable more complete conversion.

Brew on :mug:
 

doug293cz

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mmills06, I am confused... You state you started with 7.5 gallons of water added 13 pounds of grain and ended up with 7.0 gallons. The usual absorption rate of grain is around 1 pint a pound, so you should have been around 6 gallons pre boil, did I miss something?
BIAB grain absorption is usually under 0.1 gal/lb (1 pint/lb = 0.125 gal/lb) with a moderately long gravity bag drain. If you drain longer, absorption will be lower. If you squeeze, you can get down in the 0.05 - 0.06 gal/lb range, and maybe lower if you are a fanatic squeezer. OP's was about 0.04 gal/lb. This could be due to some measurement errors, but is not out of the ballpark.

@mmills06 - Did you squeeze the bag after the mash, and if so, how aggressively?

Brew on :mug:
 

TexasWine

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So, tonight was my first time doing a BIAB batch with my new equipment. I have an 11 gallong Bayou Classic kettle with the SS basket which I put my bag in. I was doing an IPA recipe w/ 13 pounds of grain. I heated 7.5 gallons to 161 degrees and added in the grains and the temp dropped to 153 (target mash temp of 152). I constantly stirred the grain while pouring in with a 24" whisk. Mashed at 152-3 for 60 minutes, after 60 minutes temp was at 150. The preboil hydrometer meeting came out to 1.27 @ 151 degrees and 7.0 gallons, resulting in around 62% efficiency (1.042 adjusted, but target was like 1.058?). What did I do wrong? I ended up tossing in 1lb of DME during the boil to bring up my final OG to 1.061 (target 1.067), but still, how can I get my BIAB system to be up around 70-80% like most claims i read about?
I'm with the others. Crush finer. If you got 7 gallons at 1.042 at the beginning of your boil, conversion efficiency was really, really low. It should be 85% or better (not uncommon for mine to be 95%) and yours was in the low 60s.

Another thing, I'd recommend cooling the sample before taking a hydrometer reading. I've read that the farther you get from the calibration temp the more inaccurate those conversion tables become.

But now let's talk about what you did right! First, your process looks very sound. No doubt you'll be dialing things in very soon and laughing about your first brew day over a tasty pint that you brewed. Second, you actually took gravity and volume readings at appropriate times. Boom! It's very common for people to ask for help troubleshooting, but there isn't enough data and we're all just guessing as to what the problem is. Third, you were thinking on your feet when you pulled out the DME. You rolled with it, made the best of the situation, and got beer in the end.

So kudos to you for doing a lot of stuff right!
 

eadavis80

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My first BIAB was horribly low gravity. Batch no. 2 was better. A few things I did differently this time:

1. Squeeze the bag post mash
2. Did a dunk sparge with 170 degree sparge water
3. Took an iodine test to check for compete sugar conversion prior to moving onto the boil. (reached conversion after 60 minute mash)

My efficiency is not as high as others, but it is improving, so I'm happy. I find BIAB to a be a lot of fun. After nearly 40 extract kits, while I still enjoyed brewing, it was pretty robotic. Changing things up and going to "the next level" of his hobby is a lot of fun. Good luck in your future batches!
 

BlueHouseBrewhaus

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My first BIAB brews were all around 65%. I started doing a double crush at my LHBS and went to 70%. Then I started stirring the mash every 15 minutes or so and got into the low 70s. Then I started reserving some water for a mashout and a sort of modified fly sparge with a perforated HD bucket over the raised draining basket and I now get a consistent 80%. The biggest improvements were the finer crush and the slow sparge.

All that being said, the most important thing is consistency. If you can get a consistent efficiency brew after brew, you can produce repeatable results and have much better control over your recipes.
 

BUCKNUTS

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All that being said, the most important thing is consistency. If you can get a consistent efficiency brew after brew, you can produce repeatable results and have much better control over your recipes.

This is really the most important point. I only get high 60s for efficiency after a lot of biab brew days but it is very consistent batch to batch and the beer is good.
 

pricelessbrewing

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Pretty sure I already replied to you on reddit but my advice is still the same! Crush fine, get rid of the stainless internal bucket, get your volumes straightened out.
 
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mmills06

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Thanks for all the advice! I think I may need to remeasure my volume markings. I initially did this by adding water and measuring with a SS ruler from the top of the kettle, but I should recheck them based on a lot of these comments saying they may be off. Also, I did squeeze the bag quite a bit. I pulled the basket out and put a steel grate on top of the kettle and put the basket on top of that. Then I pushed down on the bag and squeezed quite a bit out. I did order this grain as a recipe from AIH, and I did not request a finer mill of the grain so that is something I will do next time at the LHBS.

I feel better after reading some of these comments, I had just been reading about BIAB on these forums and others with people talking about hitting 80% regularly. So I dont feel as bad about the efficiency being low for my first time. Now I have some takeaways for next time. Thanks guys!
 

pricelessbrewing

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Thanks for all the advice! I think I may need to remeasure my volume markings. I initially did this by adding water and measuring with a SS ruler from the top of the kettle, but I should recheck them based on a lot of these comments saying they may be off. Also, I did squeeze the bag quite a bit. I pulled the basket out and put a steel grate on top of the kettle and put the basket on top of that. Then I pushed down on the bag and squeezed quite a bit out. I did order this grain as a recipe from AIH, and I did not request a finer mill of the grain so that is something I will do next time at the LHBS.

I feel better after reading some of these comments, I had just been reading about BIAB on these forums and others with people talking about hitting 80% regularly. So I dont feel as bad about the efficiency being low for my first time. Now I have some takeaways for next time. Thanks guys!
If you're really using a SS ruler, just measure the diameter of the kettle. The height will change at different temps, and my calculator does that conversion for your.
 

Subdivisions

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If you're really using a SS ruler, just measure the diameter of the kettle. The height will change at different temps, and my calculator does that conversion for your.
This is correct. Water expands as it gets hotter so what you measured at 70 degrees is going to be different at 150.

His calculator is pretty good too!
 

MindenMan

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I use a sort of BIAB method myself, but I move my grain out of the mash pot into a 5 gallon bucket with a false bottom and sparge through the grain bag; this extra step has helped my efficiencies improve. I occasionally get into the 80's, but my recipes are calculated at 72% and that is what I average these days.
 

MindenMan

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This is correct. Water expands as it gets hotter so what you measured at 70 degrees is going to be different at 150.

His calculator is pretty good too!
Don't all wet things expand as they get hotter? And you like his calculator, is that the current euphemism used on this website?
 

Mogwa4

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I've had efficiencies with BIAB all over the map. 70-75% mid 80's one batch at 64% and my last batch ended up in the mid 90's

The lowest result (64%) was the only batch i did not mash out the wort after the 60 min.
Basically increase the mash temp to 170 deg and let it sit for another 10 min.


Other notes:
I use a credit card to set my grain mill .062" ish.
Mash at desired temp for 60min
Increase mash temp to 170deg for 10min
And lastly always squeeze the bag.
 

doug293cz

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I've had efficiencies with BIAB all over the map. 70-75% mid 80's one batch at 64% and my last batch ended up in the mid 90's

The lowest result (64%) was the only batch i did not mash out the wort after the 60 min.
Basically increase the mash temp to 170 deg and let it sit for another 10 min.


Other notes:
I use a credit card to set my grain mill .062" ish.
Mash at desired temp for 60min
Increase mash temp to 170deg for 10min
And lastly always squeeze the bag.
If a mash out is increasing your efficiency, it is because conversion was incomplete. The higher temps of the mash out will speed up the enzyme action, until the enzymes are denatured (denaturing is not instantaneous once you get to a specific temp.) That plus the extra time, allows more conversion to occur, thus improving your efficiency. You could achieve the same result with a longer mash.

Also, I think you may have a typo in your mill gap above. I believe a credit card gives you about an 0.032" gap.

Brew on :mug:
 

Mogwa4

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You are correct, i was going by memory the mill gap is a .032-.033" gap.

Either way my only low % mash was when i did not preform additional 10min mash out. Mash out = more ferment-able wort in my kettle, the mash-out is probably more beneficial for my setup as i loose about 8deg over the hour with my non insulated keggle and conversion is as you stated probably not complete.
 
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