BiaB, fine crush, 8 hour mash, 49% efficiency ?!

So I've been getting bad efficiency. I already had one thread where the consensus was my LHBS crusher.

I got a corona and crushed 20 pounds of grain with a drill attached. Knowing that fast crushing causes problems I ziptied the trigger and let it go at a slow pace (maybe 100 rpm or so). It took about 15 minutes. The grains were well crushed, lots of flour and definitely no uncrushed grains.

I did a fullish volume BiaB, 11 gallons for the 20 pounds. My intention was a 10 gallon batch but the water went up to the top of the basket and I didn't want grains getting out of the basket. I didn't have much room to stir to make sure there were no dry pockets or anything but I poked through the grains with the spoon a few times and everything seemed fine.

The water outside the basket was 150F at this point. I covered the whole thing with a blanket (it was 80F outside) and went to work.

8 hours later it was 120F, I heated to 180 to mashout, pulled out the grains and needed to add some water to do a full boil so I had 2 more gallons at 190F that I poured through the grains (not a real sparge, I know, but I don't normally sparge at all).

As it turns out I needed more water than that, I ended the 60 minute boil with 8 gallons so when I topped it off my gravity (well stirred wort+water) was 1.040 in both fermenters. The target was 1.056.

*sigh*

I used to get low efficiencies in BIAB for the following reasons:

1. I wasn't stirring properly
2. Water to Grist ratio was too low (Not your problem obviously)
3. Wasn't sparging

That being said, I didn't realize I wasn't stirring well enough until I used a paint mixer attached to my drill. The efficiency began shooting through the roof.

This is a pic of what I'm talking about:


As long as you stir under the surface and don't let it splash, you shouldn't have to worry about HSA.

I always thought I was stirring properly, but this helped me realize the difference.


Also, until I used a second pot for sparging, my efficiencies wouldn't go higher than 50-60%. After I used a second pot for the sparge, I haven't been below 75-80%.

I use a second pot but another sparge option I've used is heating the mash out and just allowing the grains to drain then redunking 4 times and draining. I would get 70% efficiency usually which I was happy with

Yea, I've seen other people use this sparging method, I just don't have a pot big enough for my basket (it won't even fit in my old 10 gallon kettle.

Haputanlas said:

I used to get low efficiencies in BIAB for the following reasons:

1. I wasn't stirring properly
2. Water to Grist ratio was too low (Not your problem obviously)
3. Wasn't sparging

That being said, I didn't realize I wasn't stirring well enough until I used a paint mixer attached to my drill. The efficiency began shooting through the roof.

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I've seen on here saying you shouldn't mix the mash because of astringency and watery effect, or maybe this is something BiaB'ers have to do?

im thinking that your long mash may have absorbed more sugar rich wort than a typical 1 hour mash, then you has to top off that loss leading to a lower gravity, so unless you are souring a mash, I would not leave it in a mash tun for an extended period of time.

Two suggestions:

1) Next time do a double mill. A fine crush is all good, but you are still going to miss a good % of the grains altogether. Mill, dump the milled grains back in, and mill again.

2) Did you do a really good drain of the bag? I know it would be extremely difficult to squeeze a 20lb grain bag, but you have to get the wort out of there somehow. In a 20lb grian bill, there is almost 1.5 GALLONS of concentrated wort in the bag after the mash. A sparge isn't going to get all of that out. You HAVE to either be able to squeeze the crap out of it, or at least suspend it above the kettle for about 25-30 min. If not, you are missing out on all of that concentrated wort and your efficiency is going to suffer for it.

TopherM said:

Two suggestions:

1) Next time do a double mill. A fine crush is all good, but you are still going to miss a good % of the grains altogether. Mill, dump the milled grains back in, and mill again.

2) Did you do a really good drain of the bag? I know it would be extremely difficult to squeeze a 20lb grain bag, but you have to get the wort out of there somehow. In a 20lb grian bill, there is almost 1.5 GALLONS of concentrated wort in the bag after the mash. A sparge isn't going to get all of that out. You HAVE to either be able to squeeze the crap out of it, or at least suspend it above the kettle for about 25-30 min. If not, you are missing out on all of that concentrated wort and your efficiency is going to suffer for it.

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I set the corona to grind finely, there were definitely not uncrushed grains, there was plenty of flour in fact.

The bag did sit above the kettle for probably 20 minutes, I normally press down with a pan lid but I didn't this time because of the small amount of room I had to work with.

If you didn't stir enough, you could have had a lot of dough balls. That will kill efficiency. I've found that a finer crush will cause more dough balls requiring a lot more stirring and crushing of the dough balls.

So....excuse my ignorance here, but why would you ever mash a regular beer for 8 hours?

Here are some trouble shooting questions for you.

1. Can you take a picture of what your crush looks like? I am wondering if your mill is just chopping the grain in to pieces rather than crushing.

2. When you mash in what is your process?

3. What kind of material are you using for your bag.

4. What were your grain proportions for this recipe?

I consistantly get 90% efficiency and follow a really simple process.

No way you did even close to a full voulume for a 10 gal batch, with 20 lbs of grain. I usually end up with around 8 gallons of water for mash in on a 5 gallon batch with 10-11 lbs of grain.

Brewsmith is showing me around 14.5 gallons for a 10 gal batch. If your not doing full volume you would need to sparge to increase your eff.

JeepDiver said:

No way you did even close to a full volume for a 10 gal batch, with 20 lbs of grain. I usually end up with around 8 gallons of water for mash in on a 5 gallon batch with 10-11 lbs of grain.

Brewsmith is showing me around 14.5 gallons for a 10 gal batch. If you’re not doing full volume you would need to sparge to increase your eff.

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Also this would probably take a 25 gallon kettle to pull off a full volume mash, which means your boil off would probably be higher, putting you closer to 16-17 gallons for full volume

You say you were afraid your grain was going to come out of the basket if you mashed at full volume. Sounds to me that your grain was too compact. Giving your grains enough space and stirring should shoot your efficiency way up.

SenorPepe said:

So....excuse my ignorance here, but why would you ever mash a regular beer for 8 hours?

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This was my thought exactly. I don't know how you could troubleshoot issues when you have that sort of thing in the procedure....who knows what went on in that 8 hours!!!

manicmethod said:

The bag did sit above the kettle for probably 20 minutes, I normally press down with a pan lid but I didn't this time because of the small amount of room I had to work with.

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My suspicion is that there is a fair amount of wort that "must" be squeezed from the grains. Last time I was brewing (biab), I left my grain bag suspended to drip for quite some time. After it stopped dripping I squeezed it hard and repeatedly and continued to extract quite a bit of wort. In fact, it went on for so long, I gave up before it stopped yielding a measurable amount. This was with an 8.5lb grain bill and a conventional length mash. I'm thinking this could have been a big issue with your large grain bill and super long mash.

broadbill said:

This was my thought exactly. I don't know how you could troubleshoot issues when you have that sort of thing in the procedure....who knows what went on in that 8 hours!!!

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It's so out there in terms of what I've done and read that there must be a reason for it though. I'm sure OP didn't just up and decide "well, if a 60-90 minute mash is good, then a 480 minute mash must be better!"...right?

he said he had to go to work, so yeah I think thats exactly what he said.

It may not have been a mash with full water, but he said he used 11 gallons of water to the 20lbs of grain. That is a 2.2 qt/lb mash. Plenty for good efficiency.

I've heard of overnight mashes, but other than a sour mash, I don't understand the point. But I don't think you lose efficiency from an 8 hour mash.

manicmethod said:

The water outside the basket was 150F at this point. I covered the whole thing with a blanket (it was 80F outside) and went to work.

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Do you measure temperature of your water surrounding grain during mash and not the grain themselves? If so your grain bed may be as low as 135-140 F which not going to get you much conversion. I usually stick my thermometer right in the grain not the water surrounding it and monitor it from there (I also BIAB in a basket lined with 5 gal paint strainer bag). From my observations temperature of the water can change rapidly where grain bed even well stirred will raise or lower temperature much slower with all that thermal mass.

manicmethod said:

I've seen on here saying you shouldn't mix the mash because of astringency and watery effect, or maybe this is something BiaB'ers have to do?

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Not at all. I actually got this idea from Yuri Rage and haven't gone back since.

As I mentioned before, you just have to be careful of HSA if you splash around and get Oxygen in the hot wort.

Also, I use very low speeds for the mixing. No need to get wort everywhere

SenorPepe said:

So....excuse my ignorance here, but why would you ever mash a regular beer for 8 hours?

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I wanted to do a mid-week brew and wouldn't have time to do the entire thing after work so I figured I could mash during work and boil after. I saw in the BYO article when they were trying to get a 25+% beer from all grain (no sugars) they mashed over night to maximize extraction.

paraordnance said:

Do you measure temperature of your water surrounding grain during mash and not the grain themselves? If so your grain bed may be as low as 135-140 F which not going to get you much conversion. I usually stick my thermometer right in the grain not the water surrounding it and monitor it from there (I also BIAB in a basket lined with 5 gal paint strainer bag). From my observations temperature of the water can change rapidly where grain bed even well stirred will raise or lower temperature much slower with all that thermal mass.

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Outside the grains. My previous batches had much less grain so I don't think they affected the overall temperature much (in the past the temperature only seemed to drop about 1-2F by adding the grain.)

ShakerD said:

Here are some trouble shooting questions for you.

1. Can you take a picture of what your crush looks like? I am wondering if your mill is just chopping the grain in to pieces rather than crushing.

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I can next time I do it but based on this thread I might change the gap anyway. My impression was that you didn't normally want to grind the grain to pieces because you could get a stuck mash, but that doesn't happen with BiaB so it doesn't matter. Am I completely wrong on this?

ShakerD said:

2. When you mash in what is your process?

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Heat water to strike temp, drop grains in, stir for a few seconds, put the lid on and walk away

ShakerD said:

3. What kind of material are you using for your bag.

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I use this: http://stores.mdhb.com/-strse-349/BAG%2C-SPARGE-7.8-GALLON/Detail.bok

ShakerD said:

4. What were your grain proportions for this recipe?

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86% pale, 9% crystal 60, 2.2% acidulated, 2.2% dextrine

manicmethod said:

I can next time I do it but based on this thread I might change the gap anyway. My impression was that you didn't normally want to grind the grain to pieces because you could get a stuck mash, but that doesn't happen with BiaB so it doesn't matter. Am I completely wrong on this?



Heat water to strike temp, drop grains in, stir for a few seconds, put the lid on and walk away



I use this: http://stores.mdhb.com/-strse-349/BAG%2C-SPARGE-7.8-GALLON/Detail.bok



86% pale, 9% crystal 60, 2.2% acidulated, 2.2% dextrine

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Everything you are doing sounds good. I can make a couple of suggestions that helped me increase efficiency.

Yes grinding the malt very fine is not an issue with BIAB. I have my barley crusher set at the smallest setting. Before I changed the setting I had terrible efficiency.

This wiki has a lot of good information and pictures comparing different crushes.

When I mash in I stir constantly and slowly sprinkle on the malt. I find that with my crush I get nonstop dough balls if I don't. It also insures that the temperature is consistent within the mash. Don't worry about getting astringency, tannins or HSA from doing this, they are all boogeymen.

Another suggestion is to zip tie the bag shut. This way you could dunk sparge and make sure you are extracting all the sugars. Heating the sparge water is unnecessary and there is information on cold water sparging in this forum.

You might need a lifting device to dunk sparge but it doesn't have to be fancy. A ladder, a 2x4 works and a rope works.

Oh and absolutely squeeze the bag. You can even squeeze in between dunks.

Cheers

manicmethod said:

I've seen on here saying you shouldn't mix the mash because of astringency and watery effect, or maybe this is something BiaB'ers have to do?

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who knows where this idea came from but it's wrong. stirring the mash has nothing to do with astringency or beer being watery. inadequate stirring of the mash can most certainly be a cause of low efficiency. large breweries have automated mash paddles that churn the mash up pretty good.

Ensure you don't have any dough balls floating around in you mash, they can really mess up your efficiency. The finer you crush, the easier it is to get dough balls. likely not the problem, but thought I would mention it. FWIW, I started conditioning my grain, which helps prevent dough balls in my experience (just based on empirical observation).

Just one other cause, though I think the others mentioned are more likely (particularly crush - my single biggest efficiency improvement).

It takes me a good 10 minutes to find and crush all of the dough balls I get. This is with stirring like crazy and slowly adding the grain. It's definitely an issue with a fine crush. So if you crush fine and don't stir, you can definitely lose a lot of efficiency. You'd be better off with a normal crush if you don't want to stir.

I agree when I add the grains I stir the piss out of it until my arm gets tired. Eff %75

As a follow up to this I racked this to secondary (it was split between 2 fermenters, one wlp575 and one wlp090) and the SG's were 1.000 and 1.002 @ 60F respectively... I guess the all day mash did something if it didn't help with efficiency...

manicmethod said:

As a follow up to this I racked this to secondary (it was split between 2 fermenters, one wlp575 and one wlp090) and the SG's were 1.000 and 1.002 @ 60F respectively... I guess the all day mash did something if it didn't help with efficiency...

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I don't know if you can attribute that to a longer mash.

Your mash temps are more likely to affect attenuation.

Is it possible that OP's thermometer is off? Mashing at 140 instead of 150 would certainly cause low efficiency. I have three digital and one analog thermometer, and I found out that one of my digitals was reading up to 8 degrees off.

Also, I understand that longer mashes increase fermentability. I use a long mash on my beers I want to dry out.

In my last batch (not the one being referenced here) I used 3 thermometers and they got 3 different temperatures with the highest being 10 degrees over the lowest. Obviously this accuracy isn't adequate for brewing, what do you guys use?

I use a thermometer that can be calibrated. I put it in ice water before I brew to make sure it's at 32F. I figured this out after it was over 30F off on my first batch.

manicmethod said:

In my last batch (not the one being referenced here) I used 3 thermometers and they got 3 different temperatures with the highest being 10 degrees over the lowest. Obviously this accuracy isn't adequate for brewing, what do you guys use?

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Spend your money on a good one you can trust it doesn't have to be expensive

This a good one

Unless you want to spend the big bucks

If you are buying a dial thermometer, put it in a pot of boiling water and calibrate it to 212F/100C with the nut under the dial.

If you are buying a "tube" thermometer, look at the temperature readings all on the ones in the store and buy the one closest to middle of the pack.

Or, put your current thermometer in boiling water and write down how much you need to add/subtract from the reading to get 212F/100C, then use this adjustment factor when you take a reading. For hot wort, 212F is closer to the temps you'll be reading than calibrating against 32F/0C ice water.