Author Topic: Low Efficiency Mash in BIAB  (Read 718 times)

Offline itsjoao

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Low Efficiency Mash in BIAB
« on: June 24, 2022, 03:14:24 pm »
Hey guys.
 I've recently switched to a mixture of BIAC and BIAB and no sparge method and my efficiency is always really low (<65%)

I would easily reach 70% in a fly sparge method, and everything else in the process is mostly the same.

I have my own mill and even double milling won't help.
I'm not sure what to do anymore, or maybe low efficiency is normal in BIAB?

More Context:
I recirculate most of the time during mashing.
Temperature ranging from 150 to 158 F depending on recipe.
Finely crush grains.
I use a bag on top of a grain basket.
I usually squeeze the grains after mashing.
I do mash outs.
Always test for starch conversion and results are good.
Usually go for a full volume mash

I'm thinking of going back to sparge because that usually increases my efficiency about 3%, but what's the point of having a BIAB setup and sparging right?

Is this normal efficiency? Am I overlooking something?

Any help is appreciated thanks

Offline ynotbrusum

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Re: Low Efficiency Mash in BIAB
« Reply #1 on: June 24, 2022, 03:36:51 pm »
Taking a WAG - perhaps the grain is not getting rinsed well enough in your recirculation process to clear the sugars from the grains (this could be just simple channeling or it could be due to heavy teig or similar accumulation/blockage at the surface of mash).  Cutting the surface with a knife or other edged object (I have used the SS mash paddle I have) might help or simply try raking the top portion of the mash every few minutes.

Lastly, you might want to try batch sparging with frequent stirring during the initial mash.
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Offline itsjoao

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Re: Low Efficiency Mash in BIAB
« Reply #2 on: June 24, 2022, 04:07:40 pm »
Taking a WAG - perhaps the grain is not getting rinsed well enough in your recirculation process to clear the sugars from the grains (this could be just simple channeling or it could be due to heavy teig or similar accumulation/blockage at the surface of mash).  Cutting the surface with a knife or other edged object (I have used the SS mash paddle I have) might help or simply try raking the top portion of the mash every few minutes.

Lastly, you might want to try batch sparging with frequent stirring during the initial mash.

It does gets a little clogged sometimes and I have to stir to get the wort flowing. I do think It could be something with rinsing. Maybe I'm doing something wrong lautering?
I dunno, maybe I'll just go back to sparging haha.

Offline DBhomebrew

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Re: Low Efficiency Mash in BIAB
« Reply #3 on: June 24, 2022, 05:16:20 pm »
Given a constant pre-boil volume, a batch sparge will give you ~8% mash efficiency over no sparge. Two batch sparges will give another smaller bump. Three, another very small bump approaching a well performed fly sparge.

Best efficiency gains are achieved when runoff volumes are equal-ish within 60:40 or so.

Why BIAB with a sparge? Same as 3-vessel. Increasing brewlength, increasing gravity, increasing efficiency.
« Last Edit: June 24, 2022, 07:39:44 pm by DBhomebrew »

Offline BrewBama

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Low Efficiency Mash in BIAB
« Reply #4 on: June 24, 2022, 07:34:55 pm »
I think efficiency is based on a calculation that can be manipulated.

For example: according to BeerSmith I get ~70% brewhaus efficiency — No Sparge, Mash in a bag in my MLT, and lauter into a boil kettle when the mash is complete. I leave behind nasty crap in the MLT and the BK.

If I would sparge, or simply dump all the contents of the MLT into the BK, or BK into the fermenter post boil, my efficiency would jump dramatically. …but I don’t want to do that. I want to xfer clear sweet first run wort to the BK, whirlpool and leave the trüb (with an umlaut) behind in the BK in an effort to get clear-ish bitter wort in the fermenter.

I compensate for those losses by simply adding a bit more grain and water.  IOW, efficiency is just a number that I use as a benchmark. As long as I hit my intended volume, at my intended SG, in my fermenter that’s all I really care about. Everything I do before that to ensure that happens has been determined thru experience. I ‘over-brew’ to get my desired results — efficiency be damned. It doesn’t bother me that I spend ~$3 more to get there.

Now, having said that, I am not haphazard about my processes.  I have gone to the trouble of setting my mill with sieves to ensure I get the right balance of crush v lauter for my system, I am anal about mash pH, I mash based on a test I did a cpl yrs ago vs an arbitrary 60 minutes, I boil at the same power setting each brew, I whirlpool to get as much as I can from the BK, etc…
« Last Edit: June 25, 2022, 06:05:40 am by BrewBama »

Offline majorvices

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Re: Low Efficiency Mash in BIAB
« Reply #5 on: June 24, 2022, 07:48:04 pm »

I'm not sure what to do anymore, or maybe low efficiency is normal in BIAB?



Yes, it can be a good bit lower. And if you are only getting 70% fly sparging then 60% is probably about right.

I know you said you double mill but you should look closer at your crush.

Offline fredthecat

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Re: Low Efficiency Mash in BIAB
« Reply #6 on: June 24, 2022, 08:52:17 pm »
im harf into a 11.5% homebrew rn, but i ctrl+f'd "ph" and didn't see it here.

i include a percentage (1-3%) of acidulated malt in almost any brew i do under 25SRM

Offline DBhomebrew

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Re: Low Efficiency Mash in BIAB
« Reply #7 on: June 25, 2022, 08:11:49 am »
BIAB efficiency need not be lower than 3 vessel.

I BIAB in my BK and consistently achieve 92% mash efficiency on a typical 1.042 wort. Single room temp dunk (batch) sparge in a bottling bucket. I open the bag in the sparge and give it a good mix. Equal runoffs. Easy, gentle squeeze of each runoff as well.

I don't chase high efficiency numbers. Consistency and predictability is my goal. Consistency and repeatability in process allows for a high degree of predictability. My realized output is typically within .001 in gravity and ~1.5oz in volume of my intended recipe.

Tightening and dialing in my process has landed me with high efficiency as a fortuitous secondary outcome.

Offline denny

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Re: Low Efficiency Mash in BIAB
« Reply #8 on: June 25, 2022, 08:48:07 am »
Given a constant pre-boil volume, a batch sparge will give you ~8% mash efficiency over no sparge. Two batch sparges will give another smaller bump. Three, another very small bump approaching a well performed fly sparge.

Best efficiency gains are achieved when runoff volumes are equal-ish within 60:40 or so.

Why BIAB with a sparge? Same as 3-vessel. Increasing brewlength, increasing gravity, increasing efficiency.

Where did you get those efficiency numbers?
Life begins at 60.....1.060, that is!

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Offline DBhomebrew

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Re: Low Efficiency Mash in BIAB
« Reply #9 on: June 25, 2022, 11:00:07 am »
Given a constant pre-boil volume, a batch sparge will give you ~8% mash efficiency over no sparge. Two batch sparges will give another smaller bump. Three, another very small bump approaching a well performed fly sparge.

Best efficiency gains are achieved when runoff volumes are equal-ish within 60:40 or so.

Why BIAB with a sparge? Same as 3-vessel. Increasing brewlength, increasing gravity, increasing efficiency.

Where did you get those efficiency numbers?

From various places including the charts within sections 3 & 4 of this page at braukaiser's blog.

https://braukaiser.com/wiki/index.php/Batch_Sparging_Analysis

Offline chinaski

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Re: Low Efficiency Mash in BIAB
« Reply #10 on: June 25, 2022, 11:06:45 am »

I don't chase high efficiency numbers. Consistency and predictability is my goal. Consistency and repeatability in process allows for a high degree of predictability.
THIS.  With consistency you can design recipes reliably.  Without it, you can't.

You could calculate how much grain you are saving by chasing higher efficiency; I bet this might help convince you to relax and brew consistently.

Offline redrocker652002

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Re: Low Efficiency Mash in BIAB
« Reply #11 on: June 25, 2022, 12:53:05 pm »
BIAB efficiency need not be lower than 3 vessel.

I BIAB in my BK and consistently achieve 92% mash efficiency on a typical 1.042 wort. Single room temp dunk (batch) sparge in a bottling bucket. I open the bag in the sparge and give it a good mix. Equal runoffs. Easy, gentle squeeze of each runoff as well.

I don't chase high efficiency numbers. Consistency and predictability is my goal. Consistency and repeatability in process allows for a high degree of predictability. My realized output is typically within .001 in gravity and ~1.5oz in volume of my intended recipe.

Tightening and dialing in my process has landed me with high efficiency as a fortuitous secondary outcome.

This is very interesting to me.  So, what you are saying is you take the bag out of the Kettle, have a bucket ready and dunk the bag into the bucket?  The give it a good stir and squeeze?  I never thought of that.  Can you half the water and do a second sparge or dunk?  I guess you could also have sparge water (170 degrees or so) at the ready, put the grain bag into a separate bucket or vessel, rinse it, dunk it, squeeze it and then transfer that to the wort in the kettle?  I am very interested in how this might work, as my numbers never come close to what they should based on Brewfather's estimates.  I know I won't hit them exact, but I think I might give this a try. 

Offline denny

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Re: Low Efficiency Mash in BIAB
« Reply #12 on: June 25, 2022, 12:58:39 pm »
BIAB efficiency need not be lower than 3 vessel.

I BIAB in my BK and consistently achieve 92% mash efficiency on a typical 1.042 wort. Single room temp dunk (batch) sparge in a bottling bucket. I open the bag in the sparge and give it a good mix. Equal runoffs. Easy, gentle squeeze of each runoff as well.

I don't chase high efficiency numbers. Consistency and predictability is my goal. Consistency and repeatability in process allows for a high degree of predictability. My realized output is typically within .001 in gravity and ~1.5oz in volume of my intended recipe.

Tightening and dialing in my process has landed me with high efficiency as a fortuitous secondary outcome.

This is very interesting to me.  So, what you are saying is you take the bag out of the Kettle, have a bucket ready and dunk the bag into the bucket?  The give it a good stir and squeeze?  I never thought of that.  Can you half the water and do a second sparge or dunk?  I guess you could also have sparge water (170 degrees or so) at the ready, put the grain bag into a separate bucket or vessel, rinse it, dunk it, squeeze it and then transfer that to the wort in the kettle?  I am very interested in how this might work, as my numbers never come close to what they should based on Brewfather's estimates.  I know I won't hit them exact, but I think I might give this a try.

The more sparging (dunks) you do, the less buffering power the grain will have and the more you'll have to deal with pH.
Life begins at 60.....1.060, that is!

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The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

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Offline DBhomebrew

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Re: Low Efficiency Mash in BIAB
« Reply #13 on: June 25, 2022, 01:22:56 pm »
BIAB efficiency need not be lower than 3 vessel.

I BIAB in my BK and consistently achieve 92% mash efficiency on a typical 1.042 wort. Single room temp dunk (batch) sparge in a bottling bucket. I open the bag in the sparge and give it a good mix. Equal runoffs. Easy, gentle squeeze of each runoff as well.

I don't chase high efficiency numbers. Consistency and predictability is my goal. Consistency and repeatability in process allows for a high degree of predictability. My realized output is typically within .001 in gravity and ~1.5oz in volume of my intended recipe.

Tightening and dialing in my process has landed me with high efficiency as a fortuitous secondary outcome.

This is very interesting to me.  So, what you are saying is you take the bag out of the Kettle, have a bucket ready and dunk the bag into the bucket?  The give it a good stir and squeeze?  I never thought of that.  Can you half the water and do a second sparge or dunk?  I guess you could also have sparge water (170 degrees or so) at the ready, put the grain bag into a separate bucket or vessel, rinse it, dunk it, squeeze it and then transfer that to the wort in the kettle?  I am very interested in how this might work, as my numbers never come close to what they should based on Brewfather's estimates.  I know I won't hit them exact, but I think I might give this a try.

Yep, pretty much.

Mash in kettle. Pull bag, let hang via a self-locking pulley on a fixed line above. Let hang ~15m until stream breaks into drips. 'Squeeze' via twisting the top of the bag. This is a small, gentle, easily repeatable amount of pressure. When this stream breaks into drips, letting the twist out will stop the drip. This gives me ~.08gal/lb absorption. Move bag to room temp water in a nearby bucket. Flame on. Open bag, stir well, close bag, pull. Let hang, twist, etc. Pour sparge into kettle.

Repeat as desired. Take any precautions, such as pH control, one would for a 3-vessel system. Each sparge will give diminishing gains over the last.
« Last Edit: June 25, 2022, 01:25:32 pm by DBhomebrew »

Offline fredthecat

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Re: Low Efficiency Mash in BIAB
« Reply #14 on: June 25, 2022, 01:23:16 pm »

I don't chase high efficiency numbers. Consistency and predictability is my goal. Consistency and repeatability in process allows for a high degree of predictability.
THIS.  With consistency you can design recipes reliably.  Without it, you can't.

You could calculate how much grain you are saving by chasing higher efficiency; I bet this might help convince you to relax and brew consistently.

big time, im just very happy that with my process now i can accurately predict what my gravity will be so i dont end up with a 6% german pilsner that was supposed to be 5%.

also you probably have more of a crowdsourced "mash efficiency" than i do since i use an odd brewing program. but i realized a while ago that though the program says i'm getting about "65%" efficiency. in terms of potential sugar extract per weight of grain it is in line with what people here say they get running around 75% "efficiency". ie. 10lbs of basemalt = ~1.05 gravity for 5 gallons of wort. that is good enough to make me happy.