Another BIAB Efficiency Issue Thread

[wingnut908]

Sorry to bother you guys with another BIAB efficiency issue, but I need help figuring out why I’m only ever getting 50% brewhouse efficiency. When I first started brewing 10 batches ago I was doing a lot wrong which on average gave me 50% eff. But since then, using a lot of troubleshooting information from you folks on this forum (thanks btw), I had changed a few things:

-Increase mash time to 90 min (originally just doing 60)
-Closing mill gap to the width of a credit card (0.035”)
-milling twice
-squeezing grain bag out at end of mash

With these common issues fixed, I would have thought this would have given me at least a little bump in efficiency, but as of my 10th batch, I got exactly 50% BH eff which is pretty much the same as my first (and my last 9).

My current brewing method:

1) Double crush 1 kg (2.2lb) 2 row grain @ 0.035”
2) Heat 2.5 gallons of mash water to between 160-165F (usually closer to 165F)
3) Dump mash water in to cooler
4) Toss BIAB with grains in at once, stirring to remove all dough balls (I’ve heard this is just as effective as slowly adding grains to mash, especially since I pay extra attention to breaking up balls)
5) Mashing for 90 min (recently changed from 60 min), coming back to stir at 3 different times (Gravity = 1.028-1.030)
6) Remove BIAB (end temp = 150F @ 60 min, 145F @ 90 min), transfer 2.5 gallons of wort to kettle and turn on stove (usually takes 13-18 min to reach boil), squeeze out biab and transfer to kettle while waiting for boil
7) Rolling boil for 60 min, hop additions as per recipe
8) Chill 1.5 gallons (boil off loss = 1 gallon) with wort chiller to room temp
9) Transfer 1 gallon to fermenter
10) Pitch yeast

I have used this same recipe (other than changing the hops) for the last 9 batches and have not changed anything else. On my most recent 10th batch where I first tried mashing for 90 min, my fermentables were:

1) 1 kg pale 2 row

2) 0.1 kg Crystal 20L

3) 0.05 kg flaked wheat


By the way when I say brew house efficiency, I mean the OG just before I pour in to fermenter with no yeast vs what it should with 100% sugar conversion. When I go to the Brewers Friend calculator (https://www.brewersfriend.com/brewhouse-efficiency/) I input 1 gallon water, OG measurement of 1.040, and 2.2 lbs of American Pale 2 Row, and it gives me 49.14% efficiency.

I really hope I am just missing some curtail and obvious step and you guys will have some magical solution that bumps my brew house efficiency up 30% and I can feel like an idiot.


Cheers

EDIT: Added boil off volume and mash gravity

 

[RM-MN]

Tighten your mill. If the grain isn't getting crushed the starches don't get converted. Quickest way to increase efficiency is to crush the grain finer. I'd start by adjusting the mill to .025", then tighter than that if you can get the grains to feed through.

 

[beermanpete]

Two things stick out:

1) The strike temp. seems rather high. What is the mash temp during the first 5 or 10 minutes?

2) It seems you are only fermenting 1 gallon. There should be another 1/2 to 3/4 gallon of wort left in the kettle. What are you doing with that?

 

[dmtaylor]

You're not crushing hard enough. Go down to 0.025". That will help more than anything.

Also I wonder, what is your mash pH? Aim for 5.2-5.3. With a SMASH beer, pH is likely much higher, closer to 5.8, which will hurt your efficiency.

 

[seilenos]

Before making process changes, I believe there are some data points missing that may help identify the issue.

What is your gravity and volume after mashing but before boiling? This will let you calculate your mash efficiency.

What is your gravity and volume after boiling but before transferring to the fermenter?

You say 1 gal/1.040 but I read that as what goes into the fermenter which may be different than the question asked and, since it doesn't take into account losses such as dead space and residual break material, could significantly affect the BH calculation.

Even having the just the volume for each question above might be enough information to help out.

 

[soccerdad]

Roughly 1G per pound of grain is a really thin mash. What is your target volume into the fermenter? What are you getting in these 10 batches?

 

[FunkedOut]

What is your mash efficiency?
(see sellenos post above)

If your mash efficiency is good and your bh efficiency is still 50%, you may be looking in the wrong place.

 

[seilenos]

To expand on the point I was trying to make (and what beermanpete questions above)...

If you started with 2.5 gal of water, with that crush and you squeezing I would expect your absorption losses to be .25 gal at most (and that would be high).

That means 2.25 gal of wort at the start of the boil.

Given a 15% boil off rate per hour means you should end up with roughly 1.9 gal after the boil.

I entered your recipe into BrewSmith and came up with a calculated OG 1.040. Since you say you put 1 gal @ 1.040 into the fermenter, I see two possibilities:

1) Your mash efficiency is really bad and you are boiling down to close to 1 gal to get it up to the expected OG of 1.040.
2) You are leaving a lot of wort behind in your brew kettle.

This is why I asked about volumes because that would point to one possibility or the other.

 

[dmtaylor]

One more thought: At what temperature are you measuring the OG? If it's still warm, you need to adjust for temperature because the gravity reading will be WAY off if not at room temperature.

 

[dstockwell]

Two things stick out:

1) The strike temp. seems rather high. What is the mash temp during the first 5 or 10 minutes?

Got to agree with this, mash temp looks way to high for the volume. I BIAB 3G batches and dump 7lbs or so grains in 5G water @ 156F. I use a corona mill and have 70% brewhouse efficiency.

 

[chickypad]

DISREGARD, SEE POST BELOW
Are you measuring you temp just after mash in? I just mashed 5lb grain in 2.5 gals last batch and needed at 157 to hit mash temp of 150, but I have used strike water as high as 163 to hit mash of 155. Your conversion efficiency looks really off. 2.2 kg or 4.85 lb would be a mash thickness of 2.06 qt per lb, your initial runnings should be in the low 1.060's per Kai's table below. So let's say you had 2.16 gal at end of mash (.07 gal per lb loss for BIAB that's average) and boiled that down to 1.66 or so to 1.040. That means your original 2.16 gals would be like 1.031, or about 50% conversion efficiency - horrible. I don't think a slightly high mash temp or a 0.35 crush accounts for that. You'd have to practically not crush at all, or mash really high like over 160. Have you calibrated everything - thermometers, hydrometer, etc.? Measuring volumes accurately? What about pH?

I would say
- check all calibrations
- get a very accurate initial dough in temp after a good stir, make sure you aren't too high
- measure accurately and record all volumes - initial boil volume, post boil volume and get accurate gravities on both (as someone mentioned above - measured at room temp)
- look at your water and pH if you aren't already

http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency

Edit: corrected for absorption, doesn't change the efficieny number

 

[chickypad]

Hang on, I'm an idiot and read your grainbill as 2.2 kg. At 2.2 lbs that is much more like it - if you figure efficiency for what you mush have actually had post boil (even more than 1.66) then you are up in the 80's overal at least. So looks like it can be explained by you being way over volume and losses. More reasonable numbers for your size batch would be .15 gal loss to grain, about .35 gal loss to boil, if you want to leave a little extra in the fermenter for trub say 1.25 gals. That means 1.75 gals strike. You should easily be able to get a mid 1.050's beer with that.

Sorry for the earlier post, worked graveyard last night (-:

 

[seilenos]

While I agree the mash temp seems high and may warrant further discussion related to conversion and FG, a mash temp in the range described won't change OG and efficiency all that much, if at all.

I bring that up so that OP doesn't get the wrong idea about the cause of the efficiency issue.

 

[wingnut908]

Thanks for all of your responces! I'm going to respond in multiple posts so quoting doesn't get out of hand.

Tighten your mill. If the grain isn't getting crushed the starches don't get converted. Quickest way to increase efficiency is to crush the grain finer. I'd start by adjusting the mill to .025", then tighter than that if you can get the grains to feed through.

Ok. I'd say my crush is already very fine and on par with other BIABers but I'll give your recommendation a shot if you think that's what is holding me up.

 

[wingnut908]

1) The strike temp. seems rather high. What is the mash temp during the first 5 or 10 minutes?

2) It seems you are only fermenting 1 gallon. There should be another 1/2 to 3/4 gallon of wort left in the kettle. What are you doing with that?

1) I kind of thought so too, but once everything settles in the temp usually gets to 156F for the first 15 min (which is where it should be to my understanding). Beersmith goes as far as to recommend a strike temp of 168F, but from my understanding that's getting close to a danger zone where it could freeze up conversion. What do you think is an ideal strike temp?

2) I measured there to be 2.5 qts left over. I realize that is a lot and I'll fix it sometime, but for right now I want to keep that factor consistent while I troubleshoot this efficiency issue. Right now my priority is getting my OG closer to what it is supposed to be, then after I'll worry about the few cents I'm loosing from my unused wort.

 

[wingnut908]

You're not crushing hard enough. Go down to 0.025". That will help more than anything.

Also I wonder, what is your mash pH? Aim for 5.2-5.3. With a SMASH beer, pH is likely much higher, closer to 5.8, which will hurt your efficiency.

Ok. Like I mentioned to RM-MN my crush looks ok, but since you're the second person to mention it I will definitely give it a shot for my next batch.
I was wondering if it was my pH too, so on my 8th brew I picked up some pH strips from the LHBS. Unfortunately I didn't realize how poor the resolution is on them (no noticeable difference between a pH of 5 and 6) , or if they even work. I'll buy these (https://www.amazon.ca/dp/B00M0FQ4JE/?tag=skimlinks_replacement-20) for my next batch and see if pH is the issue. Do you know a better way to measure pH other than with an expensive meter?

One more thought: At what temperature are you measuring the OG? If it's still warm, you need to adjust for temperature because the gravity reading will be WAY off if not at room temperature.

I chill my wort to room temp (same temp as hydrometer calibration) before measuring. I have made this error before though but thankfully realized it and corrected it to the proper temp.

 

[wingnut908]

Roughly 1G per pound of grain is a really thin mash. What is your target volume into the fermenter? What are you getting in these 10 batches?

My target volume for the fermenter is 1 gallon, though I have 2.5 qts left over in the kettle once I fill the fermenter up. then about 0.1 gallon of turb loss in fermenter.

 

[wingnut908]

Before making process changes, I believe there are some data points missing that may help identify the issue.

What is your gravity and volume after mashing but before boiling? This will let you calculate your mash efficiency.

What is your gravity and volume after boiling but before transferring to the fermenter?

You say 1 gal/1.040 but I read that as what goes into the fermenter which may be different than the question asked and, since it doesn't take into account losses such as dead space and residual break material, could significantly affect the BH calculation.

Even having the just the volume for each question above might be enough information to help out.

What is your mash efficiency?
(see sellenos post above)

If your mash efficiency is good and your bh efficiency is still 50%, you may be looking in the wrong place.

My gravity after mash is 1.028-1.030 (I'll edit my original post and add in that data along with volumes). When you say after boiling but before transferring, do you mean gravity before chilling? To measure my OG, I stick my siphon in to my kettle after chilling and fill up the test tube for my hydrometer reading (with out yeast in the wort). Once its full I siphon the rest in to my fermenter. Is this not how my OG reading should be taken?
Dead space in the fermenter or kettle? I guess there is 2.5 qts left in the kettle because I can't fit the rest in my fermenter so maybe you could call that dead space. And by residual break up is that like turb? If so I do loose about 0.1 gallon in my fermenter.

 

[wingnut908]

Seilenos and chicky.pad you might be on to something.

At first I kind of disregarded the issue of having 2.5 qts left in the kettle because it makes it easier for me to siphon (could be a little less though), but reading your posts again got me thinking. In beersmith I have my batch volume (what goes in to the fermenter) entered as 1 gallon. Maybe I should have it entered as 1.5 gallons to account for what is in my kettle, even though only 1 gallon goes in to my fermenter.

So I changed my equipment profile in beersmith to 1.5 gallon batch and then went to my recipie and updated the equipment used. When I did this, my "Est Original Gravity" shot down to 1.028 (because my efficiency is set at 52%). So I bumped my inputted "BH Efficiency" until the "Est Original Gravity" matched what I really got. This got me to 74% BH eff.

If what I did in beersmith sounds correct to you, and my BH eff sounds correct to you, then you may be correct that I had an error in calculating my BH eff.

 

[chickypad]

Yes I would set your batch volume in BS at 1.65 gals if that was your actual post chill volume. You don't need to siphon into the fermenter you can just pour. If you're worried about trub don't, it will all settle out and you'll lose a lot less volume than your current practice.

 

[wingnut908]

Yes I would set your batch volume in BS at 1.65 gals if that was your actual post chill volume. You don't need to siphon into the fermenter you can just pour. If you're worried about trub don't, it will all settle out and you'll lose a lot less volume than your current practice.

Awesome. Really glad to hear that it was just me being an idiot miscalculating my BH efficiency. Although my OG isn't quite where I want it to be but that's a simple fix and I'll make my mash a little thicker as soccerdad mentioned. Problem solved. Thanks for everyone's help!

 

[doug293cz]

Brewhouse Efficiency = Mash Efficiency * Transfer Efficiency
Transfer Efficiency = Fermenter Volume / Post-Boil Volume

With 1.5 gal post-boil, and only 1 gal to the fermenter, your transfer efficiency is only: 1.0 / 1.5 = 67%. With a 50% brewhouse efficiency, that puts your mash efficiency at: 50% / 67% = 75%, which isn't too bad, but you should be able to get mash efficiency up into the 80's with no-sparge BIAB.

The biggest hit to your brewhouse efficiency is all the wort you are leaving in the BK.

Edit: And if you really have 1.65 gal post-boil, with 1 gal to fermenter the numbers are:

Transfer Efficiency = 1.0 / 1.65 = 61%
Mash Efficiency = 50% / 61% = 82% - 83%​

You can see how big an effect transfer losses have on BH efficiency, and how important accurate volume measurements are, especially for small batches.

Brew on

 

[wingnut908]

Brewhouse Efficiency = Mash Efficiency * Transfer Efficiency
Transfer Efficiency = Fermenter Volume / Post-Boil Volume

With 1.5 gal post-boil, and only 1 gal to the fermenter, your transfer efficiency is only: 1.0 / 1.5 = 67%. With a 50% brewhouse efficiency, that puts your mash efficiency at: 50% / 67% = 75%, which isn't too bad, but you should be able to get mash efficiency up into the 80's with no-sparge BIAB.

The biggest hit to your brewhouse efficiency is all the wort you are leaving in the BK.

Edit: And if you really have 1.65 gal post-boil, with 1 gal to fermenter the numbers are:

Transfer Efficiency = 1.0 / 1.65 = 61%
Mash Efficiency = 50% / 61% = 82% - 83%​

You can see how big an effect transfer losses have on BH efficiency, and how important accurate volume measurements are, especially for small batches.

Brew on

I'll keep tinkering and see if I can get it to 80% but as for right now I'm just really happy knowing that I've got a 75% efficiency that is super repeatable and consistent.

You're definitely right on how measurement errors are amplified in small batches. Even with my new batch volume set, I think I'll try and aim for only half a quart left over on my next batch. After setting my equipment profile in beersmith of course.

 

[doug293cz]

I'll keep tinkering and see if I can get it to 80% but as for right now I'm just really happy knowing that I've got a 75% efficiency that is super repeatable and consistent.

You're definitely right on how measurement errors are amplified in small batches. Even with my new batch volume set, I think I'll try and aim for only half a quart left over on my next batch. After setting my equipment profile in beersmith of course.

BH efficiency is a really lousy metric for evaluating your mash and lauter process. I don't even calculate my own BH efficiency. The important metrics are Conversion Efficiency, Lauter Efficiency, and Mash Efficiency.

Mash Efficiency = Conversion Efficiency * Lauter Efficiency​

Conversion efficiency directly measures what percentage of the max potential sugar you actually create in the mash, and lauter efficiency measures how well you get the sugar you created out of the spent grain mass. You can use the method here to directly calculate your conversion efficiency.

Brew on

 

[beermanpete]

1) I kind of thought so too, but once everything settles in the temp usually gets to 156F for the first 15 min (which is where it should be to my understanding). Beersmith goes as far as to recommend a strike temp of 168F, but from my understanding that's getting close to a danger zone where it could freeze up conversion. What do you think is an ideal strike temp?

2) I measured there to be 2.5 qts left over. I realize that is a lot and I'll fix it sometime, but for right now I want to keep that factor consistent while I troubleshoot this efficiency issue. Right now my priority is getting my OG closer to what it is supposed to be, then after I'll worry about the few cents I'm loosing from my unused wort.

156°F right after mash-in is fine. The exact mash temp is style dependant.

Now that you have added more data it looks like you conversion efficiency is good. Your BH efficiency is low because you waste a lot of wort. Try reducing you grain and water input a bit so you end up with only about 1.25 gallons at the end of the boil. 1.75 lbs malt and 2 gallons water is the same mash thickness and should get you 1 gal. into the fermenter with very little waste.

 

[RM-MN]

I'll keep tinkering and see if I can get it to 80% but as for right now I'm just really happy knowing that I've got a 75% efficiency that is super repeatable and consistent.

You're definitely right on how measurement errors are amplified in small batches. Even with my new batch volume set, I think I'll try and aim for only half a quart left over on my next batch. After setting my equipment profile in beersmith of course.

Any left over wort is loss. Put it in a quart jar, add a bit of yeast, and stretch a piece of Saran wrap over the top. At the end of 2 weeks you will have that much more beer to drink.

I think the reason you hit the mash temp of 156 when your strike temp is ~165 is that you aren't preheating the cooler before mashing.