BIAB - Single Crush, Double Crush, Squeeze, No-squeeze Efficiencies

[JohnnyO']

Posted this on FB - but ICYMI and are interested:


I know that the fellows at Brulosphy have done two exbeeriments relating to crush size. The first one compared 0.039” and 0.025” – which was pretty close to what I wanted to know – and the test did show a big difference in OG for what was supposed to be a large beer (which I do not brew). The second tested 0.030” to as close as he could get his rollers – and showed no difference in OG for a moderate gravity beer. Taken together you can make a good case that from 0.040” and higher down to 0.030”ish – you can realize a gain in efficiency. After that, not so much.

I decided to invest a little time and malt into trying to gauge where I should have my mill (Cereal Killer) set for the beers that are brewed in a lower ABV range. I have been running it at around 0.040”. And my last efficiency (no sparge, no squeeze) was in the low 60s on my Unibrau 10-gallon system. With sparging and squeezing I was getting low to mid 70s. The first beer I ever brewed on the system was before I had my own mill. I asked the LHBS to double mill those grains (mill set at 0.042”) – and ended up missing my OG way high on that batch. So, I also wanted to test the effect of a double crush.

I used 4 batches of 4 oz each Briess Brewer’s Malt and 20 oz of water. One batch single crush at 0.040”, one batch double crushed at the same setting, one batch single pass at 0.025” (lowest CK setting) and one double pass at the same. Each batch was contained in a HD 1-gallon paint strainer and mashed at between 150 and 160F for 20 minutes. I took gravity readings on a refractometer of the wort with no squeezing and then another post squeezing (an estimated 2 oz from the squeeze added back – and ignored the amount of liquid absorbed by the grain). Here are the results for what would be the pre-boil wort gravity and efficiency:

Single Crush, No Squeeze 0.040”
10.3 Brix – 1.041 – 62.33%
Double Crush, No Squeeze 0.040”
10.6 Brix – 1.043 – 65.37%
Single Crush, w/Squeeze 0.040”
10.6 Brix – 1.043 – 72.64%
Double Crush, w/Squeeze 0.040”
10.6 Brix – 1.043 – 72.64%
Single Crush, No Squeeze 0.025”
11.0 Brix – 1.044 – 66.89%
Double Crush, No Squeeze 0.025”
11.5 Brix – 1.046 – 69.93%
Single Crush, w/Squeeze 0.025”
11.0 Brix – 1.044 – 74.32%
Double Crush, w/Squeeze 0.025”
11.5 Brix – 1.046 – 77.7%

The wort collected in the finer crush batches contained a noticeably larger amount of sediment, once left to settle overnight – than did the coarser crush wort.

Later - at the request of someone to throw conditioned grain into the mix I posted this:
https://www.facebook.com/groups/744...meqbaPcqoBen8Y6zQwn6uew8wem1I-Bbc&__tn__=R]-R
"OK Norm, I did the conditioned grain batch. But I do not believe my results - as they are so far off from the others. I'd encourage you to do the experiment yourself. I reset the mill to 0.040" based on the recommendations I read to not mill too finely - so compare these numbers to the appropriate ones above:
No Squeeze - 7.8 Brix - 1.031 - 47.13%
w/Squeeze - 8.0 Brix - 1.032 - 53.97%"

 

[semize]

Thanks for testing!

At least one variable not accounted for in the tests (as by design, not oversight) is the chance of a "stuck sparge".

For example, my second to last batch I double milled the grain in my new Barley Crusher (set to about 0.031"-0.032") and the water would not flow through the bag (a 200 micron Brew Bag) at all. I had to shimmy and squeeze the ever loving hell out of it to get the wort out. Of note, about ~40% of my grain bill was rye malt.

Going forward, at $0.99 / lb, I will be adding at least 1lb of rice hulls to every batch.

Fast forward to this past Sunday, my last batch, I single milled the grain (all barley this time) and added 1lb rice hulls to the mash. And I still ran into problems, although far less severe. The wort ended up draining ok (still needed a little prodding, but nothing like the previous batch), however the main issue was during the mashout process. The water outside the bag reached boiling before the water inside the bag hit 168 degrees...! This was despite me frantically swooshing my paddle around inside the bag, scraping the sides to let liquid mix through. Also, this issue wasn't apparent when I first started the mash as [1] much of the starches hadn't been extracted and converted to sugars yet, gumming up the works, and [2] the bag was practically fully submerged taking up all of the space in pot. After lifting the bag off the bottom to allow heating to mashout temp is what highlighted the issue.

On the plus side, this last batch I hit 80% brewhouse efficiency (88% mash efficiency), so there's that!

So my next step is to either [1] recirculate the wort during the mashout phase by pouring wort out the kettle's spigot into a bucket and pouring that back into the bag as it reheats or [2] grind my grain a bit coarser. Question is, with A will my efficiency go up {yay!) or with B will it go down (boo!) ?


PS... This last batch I let the bag containing the spent grain hang above a bucket for the duration of the boil (90 minutes), gave it a light squeeze afterwards, and the wort that had collected in the bucket still tasted pretty good to me. Couldn't detect any tannins. I'm turning into a skeptic on the whole "squeezing extracts tannins" thing.

 

[semize]

Perhaps I should get a false bottom for my pot so I don't have to worry about scorching the bag when heating the water between mash steps and can keep it fully submerged / open. So option [3]... throw money at it and don't gain or lose efficiency. Or do all three... (but I've learned my lesson more than once, only change one variable at a time, Sean!)

No that I think about it, if the water can't flow well through the bag and I make the "outside wort" area smaller by adding the false bottom to allow the bag to take up more space, then I might run into more issues with temperature variances.

I think the order of operation is [1] coarser grind to allow water to flow nicely, [2] get false bottom so I don't have to raise the bag and restrict grain to water contact when heating the mash (a pain if doing a multi rest mash), then [3] recirculate wort by hand via spigot and bucket. Ugh, then I might as well buy a pump... there's no end of stuff to buy, is there? Hmmm, but a pump wastes wort, that's a good strike against getting one.

 

[semize]

Curious, with the finer crushes why are the efficiencies different for outcomes that have the same brix / gravity reading? Shouldn't the red samples have the same efficiencies, as well as the blue?

Single Crush, No Squeeze 0.025”
11.0 Brix – 1.044 – 66.89%
Double Crush, No Squeeze 0.025”
11.5 Brix – 1.046 – 69.93%
Single Crush, w/Squeeze 0.025”
11.0 Brix – 1.044 – 74.32%
Double Crush, w/Squeeze 0.025”
11.5 Brix – 1.046 – 77.7%

 

[RM-MN]

I had to shimmy and squeeze the ever loving hell out of it to get the wort out. Of note, about ~40% of my grain bill was rye malt.

Rye has a lot of beta glcan. Think of it as glue. Very difficult to get the wort to drain.

I single milled the grain (all barley this time) and added 1lb rice hulls to the mash. And I still ran into problems, although far less severe.

There is a big difference in bags. The new one I got is a much finer weave and doesn't drain nearly as well as the one I retired. Without the rice hulls it still might have drained the same.

the main issue was during the mashout process. The water outside the bag reached boiling before the water inside the bag hit 168 degrees...!

Skip the mashout. BIAB does not need it nor does a conventional mash tun if batch sparging. It's only useful if fly sparging where the sparge take a long time and then only if full conversion has not been reached before the fly sparge starts.

gave it a light squeeze afterwards, and the wort that had collected in the bucket still tasted pretty good to me. Couldn't detect any tannins. I'm turning into a skeptic on the whole "squeezing extracts tannins" thing.

If you ever get strong enough to squeeze out tannins, let me know. I'll hire you to replace the hydraulic press to squeeze bearings into hubs. Tannin extraction requires high temps (mashout?) and high pH (over 6.0), neither of which you should get with BIAB.

 

[Miraculix]

Rye has a lot of beta glcan. Think of it as glue. Very difficult to get the wort to drain.



There is a big difference in bags. The new one I got is a much finer weave and doesn't drain nearly as well as the one I retired. Without the rice hulls it still might have drained the same.



Skip the mashout. BIAB does not need it nor does a conventional mash tun if batch sparging. It's only useful if fly sparging where the sparge take a long time and then only if full conversion has not been reached before the fly sparge starts.



If you ever get strong enough to squeeze out tannins, let me know. I'll hire you to replace the hydraulic press to squeeze bearings into hubs. Tannin extraction requires high temps (mashout?) and high pH (over 6.0), neither of which you should get with BIAB.

Mashout produces glycoproteins which greatly enhance foam stability. Don't skip the mashout!

 

[JohnnyO']

Curious, with the finer crushes why are the efficiencies different for outcomes that have the same brix / gravity reading? Shouldn't the red samples have the same efficiencies, as well as the blue?

Single Crush, No Squeeze 0.025”
11.0 Brix – 1.044 – 66.89%
Double Crush, No Squeeze 0.025”
11.5 Brix – 1.046 – 69.93%
Single Crush, w/Squeeze 0.025”
11.0 Brix – 1.044 – 74.32%
Double Crush, w/Squeeze 0.025”
11.5 Brix – 1.046 – 77.7%

The w/Squeeze and No Squeeze volumes were different - as you would expect. So with the same gravity - the efficiency has to be different.

 

[JohnnyO']

Thanks for testing!

At least one variable not accounted for in the tests (as by design, not oversight) is the chance of a "stuck sparge".

You are welcome.

I do not sparge. I brew full volume mash in a bag (Brew Bag 400u) in a basket, electric (Unibrau).

 

[RM-MN]

Mashout produces glycoproteins which greatly enhance foam stability. Don't skip the mashout!

I'm a slow drinker and find that I still have foam in the bottom of my glass after half an hour of sipping my beer. Do I need more foam stability?

 

[Miraculix]

I'm a slow drinker and find that I still have foam in the bottom of my glass after half an hour of sipping my beer. Do I need more foam stability?

You might not be in need of more foam stability, but others might be. As you were referring to a mashout step as generally useless in a biab setup, I wanted to point out that this is not the case, in general.

 

[Tom Foolery]

Thanks for testing.
I have my CK set at the thickness of a credit card and crush once. I batch sparge with 2 gal of 180-185 degree water in a separate pot. I get 70% EFF reliably. I've found that not squeezing the 200 micron 'The Brew Bag' does better. I'm just letting it drain in that other pot for 30-40 min and dumping it into the boil.

 

[enkamania]

Curious, with the finer crushes why are the efficiencies different for outcomes that have the same brix / gravity reading? Shouldn't the red samples have the same efficiencies, as well as the blue?

Single Crush, No Squeeze 0.025”
11.0 Brix – 1.044 – 66.89%
Double Crush, No Squeeze 0.025”
11.5 Brix – 1.046 – 69.93%
Single Crush, w/Squeeze 0.025”
11.0 Brix – 1.044 – 74.32%
Double Crush, w/Squeeze 0.025”
11.5 Brix – 1.046 – 77.7%

I'm Single Crush, w/Squeeze 0.025” and I get 75%

 

[JohnnyO']

I'm Single Crush, w/Squeeze 0.025” and I get 75%

Peer review confirmation!

 

[LittleRiver]

I'm consistently in the low 80's with a .025" crush (single pass with a 3 roller mill).

No sparge, no re-circulation, no squeeze (gravity drain over the kettle during the entire boil).

 

[JohnnyO']

I'm consistently in the low 80's with a .025" crush (single pass with a 3 roller mill).

No sparge, no re-circulation, no squeeze (gravity drain over the kettle during the entire boil).

If you are draining over the kettle for the entire boil - what volume are you using to calculate your efficiency?

 

[eugles]

This is great info...I've been struggling with efficiency as well and have been running my mill at .035. Even at that gap though, my wort looks absolutely disgusting. It looks like dirty muddy dishwater. I know its not supposed to be an issue, but when finish with the boil, I lose a crap ton of wort as it seems to all pancake down below and no matter how i whirlpool, i get pancake trub. Anyone getting clear wort and good efficiency at the same time??

 

[RM-MN]

This is great info...I've been struggling with efficiency as well and have been running my mill at .035. Even at that gap though, my wort looks absolutely disgusting. It looks like dirty muddy dishwater. I know its not supposed to be an issue, but when finish with the boil, I lose a crap ton of wort as it seems to all pancake down below and no matter how i whirlpool, i get pancake trub. Anyone getting clear wort and good efficiency at the same time??

Quit whirlpooling, just dump it all into the fermenter. Let the yeast act on it, use whatever they want. When the ferment is over and the yeast and trub settle you will have more beer. Bottle or keg it and give it more time to settle and you get clear beer.

Now is also the time to tighten the mill. Bring it down to .025 and if it still feeds well, tighten it some more.

 

[JohnnyO']

Now is also the time to tighten the mill. Bring it down to .025 and if it still feeds well, tighten it some more.

I have seen some evidence that from .030 down to as close as you can get them results in no increase in efficiency. Have you experienced the opposite?

 

[RM-MN]

I have seen some evidence that from .030 down to as close as you can get them results in no increase in efficiency. Have you experienced the opposite?

Being that I use a Corona mill the two don't relate well. What I have noticed it that when an adjustment came loose on my Corona and the plates weren't as tight my efficiency went down. When I tightened them back the efficiency went back to where it was. I suspect that one of the major differences may not be efficiency but mash time. The bigger the particles the longer it takes to gelatinize the starches and the longer it takes to extract the sugars. I see reference to using a 90 minute mash for BIAB, yet I get very high efficiency with a 30 minute mash. There doesn't seem to be any difference between a 30 minute and a 60 minute mash for me.

 

[Miraculix]

Being that I use a Corona mill the two don't relate well. What I have noticed it that when an adjustment came loose on my Corona and the plates weren't as tight my efficiency went down. When I tightened them back the efficiency went back to where it was. I suspect that one of the major differences may not be efficiency but mash time. The bigger the particles the longer it takes to gelatinize the starches and the longer it takes to extract the sugars. I see reference to using a 90 minute mash for BIAB, yet I get very high efficiency with a 30 minute mash. There doesn't seem to be any difference between a 30 minute and a 60 minute mash for me.

I was thinking of buying myself a Corona mill as well. I also biab and would happily buy my base malts in bulk.

Are you satisfied with the results you are getting with the mill? Have you been able to compare efficiencies between Corona milled malt and "normally" crushed malt?

 

[JohnnyO']

Being that I use a Corona mill the two don't relate well.

10-4. I had to look Corona Mill up.

For those that use a roller mill, the fellows at Brulosophy did two "Mind the Gap" exbeeriments. The first was a HG beer where a crush size of 0.039" yeilded an OG 0.010 lower than the same brew with a crush gap at 0.025". The second was a moderate gravity pale ale where the rollers were set at "credit card" gap - estimated to be 0.030" and vs the rollers set as close as they could be set without touching. For both beers in the second experiment, the OG and FG was identical. Brulosophy did not post a pre-boil gravity for either beer in either test.

 

[RM-MN]

I was thinking of buying myself a Corona mill as well. I also biab and would happily buy my base malts in bulk.

Are you satisfied with the results you are getting with the mill? Have you been able to compare efficiencies between Corona milled malt and "normally" crushed malt?

You might just be wasting $30. Have you ever wasted that amount before? It doesn't take long to pay back that $30 by buying malts in bulk. I have certain recipes that I expect to repeat often so I even bulk buy other malts like C60 and chocolate malt. That also adds to the savings.

Since the closest LHBS for me that has a mill is some 100 miles away, I have not compared the differences. I have quit trying to make 5 gallon batches because of a back problem and quit trying to use a 30 qt pot on my kitchen range since there is almost no room between it and the range hood for removing the bag of grains and instead went back to the 20 qt pot. It does not have enough room for the water plus grains to do full volume, no sparge so I started sparging to get to the volume. With the fine milling and triple (yes triple) sparging with cool water my efficiency is high enough that I can hit or exceed the expected OG with the wort within 1/2 inch of the top of the pot. That does get me sufficient wort into the fermenter that I bottle a full case plus 3 to 6 bottles extra. It also adds excitement to the brew day (or perhaps pucker factor) as I try to keep the foam from going over the rim of the pot.

 

[Miraculix]

It's not about the money, it is more about having the certainty that my grains were not lying in questionable conditions for months, being already crushed.

 

[beernutz]

Mashout produces glycoproteins which greatly enhance foam stability. Don't skip the mashout!

What is the mechanism in a mashout that enhances foam stability? I am not seeing how 15 minutes at 170ish preboil would have that result.

 

[semize]

I thought mashout was primarily to help aid final extraction. The extra heat makes the liquid less viscous, which is also a benefit for BIAB so the wort drains out of the bag faster and more completely. The reason to stop at 170 degrees is any higher temp would start to extract undesirable compounds from the grain.