BIAB Efficiency - 40%?

[IowaHomeBrewer]

I'm using a High Gravity BIAB set up, click here to see.

Just today I ran this recipe:

Amount Fermentable PPG °L Bill %
11 lb American - Pale 2-Row 37 1.8 73.3%
1 lb German - Munich Light 37 6 6.7%
1 lb American - Carapils 33 1.8 6.7%
1 lb British Light Crystal 35 10 6.7%
1 lb Corn Sugar - Dextrose 46 0.5 6.7%

I mashed at 148 for 60 minutes. Mashed out at 180 for 10 minutes.

My water volume was 9.3 gallons for the mash/boil.

I did use pH stabilizer to get pH in the right range.

60 minute boil.

I was hoping to get 70% efficiency off of this setup, and was looking for starting gravity of 1.08.

I just finished about an hour ago and took the gravity reading, it was only 1.05 which means only 40% efficiency. I was shooting for an 8% IPA and I'm going to end up with a hop bomb 5% session IPA, which is fine, just not what I was going for.

I knew BIAB was lower efficiency, but not sure what to do to get it better for next time. Here are some things I'm thinking about doing:

1.) Run all the grain through the mill twice.
2.) Change to 90 minute mash

Any other ideas on how to improve efficiency? I suppose I can just beef up the grain bill to account for it, but at 40% I've got to be doing something wrong. Thanks in advance for any suggestions.

 

[ggriffi]

What was your gravity when you checked? When I put this in at Brewers Friend at 1.040 its 63% and at 1.030 its 45%

 

[IowaHomeBrewer]

When I took the measurement it was 1.05. I must not be using Brewers Friend calculator correctly, because that is where I got my numbers from.

 

[ggriffi]

Did you correct for temp of the wort? Just asking because that is something I have done also. I'm brewing a batch of Cream of 3 Crops and I have my sample in the fridge to get the temp down so I can check it later

 

[soccerdad]

Myth #1 ..

I knew BIAB was lower efficiency

.. it's NOT. Unless you want it to be j/k

There are several things you can do to maximize conversion. As ggriffi says, you can extend the mash time. The guys from down under at biabrewer swear by this. Others crush quite fine (not just 2 passes) and can get very efficient conversion in 20 minutes. I do a hybrid ... fine crush, but not superfine, and a mash of 60 to 90 minutes. I generally get efficiency of 75% or better.

To me 9+ gallons is a lot for 5 to 5.5 going into the fermenter, but your equipment is different than mine .. for me it would be diluting the wort.

 

[pricelessbrewing]

I'm using a High Gravity BIAB set up, click here to see.

Just today I ran this recipe:

Amount Fermentable PPG °L Bill %
11 lb American - Pale 2-Row 37 1.8 73.3%
1 lb German - Munich Light 37 6 6.7%
1 lb American - Carapils 33 1.8 6.7%
1 lb British Light Crystal 35 10 6.7%
1 lb Corn Sugar - Dextrose 46 0.5 6.7%

I mashed at 148 for 60 minutes. Mashed out at 180 for 10 minutes.

My water volume was 9.3 gallons for the mash/boil.

I did use pH stabilizer to get pH in the right range.

60 minute boil.

I was hoping to get 70% efficiency off of this setup, and was looking for starting gravity of 1.08.

I just finished about an hour ago and took the gravity reading, it was only 1.05 which means only 40% efficiency. I was shooting for an 8% IPA and I'm going to end up with a hop bomb 5% session IPA, which is fine, just not what I was going for.

I knew BIAB was lower efficiency, but not sure what to do to get it better for next time. Here are some things I'm thinking about doing:

1.) Run all the grain through the mill twice.
2.) Change to 90 minute mash

Any other ideas on how to improve efficiency? I suppose I can just beef up the grain bill to account for it, but at 40% I've got to be doing something wrong. Thanks in advance for any suggestions.

a couple things that pop up.

Biab is not lower efficiency. It's usually 70-80%.
Don't do a mash out Imo just remove the grains and bring it up to a boil. Also a 180F mash out risks tannin extraction. You don't want to expose any Grain to above 170.

Ph stabilizer doesn't do its job. Leave it out, it's probably doing more harm than good. Look at the brew science forum for more info.

How did you check your volume? Being off by a quarter or half gallon can make your efficiency swing quite a bit.


My general advise for improving biab efficiency is, stir the crap out of it when you dough in and when you pull the bag. Crush the grains finer, but you need to make sure you have a good biab bag and not a coarse weave lhbs one.

 

[IowaHomeBrewer]

Not sure what you mean. The wort when I took my reading was 65 degrees.

Here is a screenshot of what I entered into Brewers Friend. Am I entering a value in wrong?

 

[ggriffi]

What soccerdad says. I usually have 9+ gallons for a 5 or 5.5G batch but that is how my equipment is dialed on for using beersmith. For the C3C's bs says 90 min mash. and for my RIS I use a 60 min mash. Also, I don't do a mash out

 

[IowaHomeBrewer]

To me 9+ gallons is a lot for 5 to 5.5 going into the fermenter, but your equipment is different than mine .. for me it would be diluting the wort.

I started with 9.3 because grain absorption was estimated at 2.8 gallons (.2 gallons per pound of grains).

My boil amount ended up at 6.5 gallons. I etched in water marks on my kettle with the vinegar/9v battery/qtip trick.

 

[wilserbrewer]

.2 gallons per pound absorption is way too high, most use ,08 or less.

Ending with an extra gallon of wort kills your gravity, monitor volume as you brew, if you are over volume in the future, boil longer and time your finishing hops to the end of the boil.

I suspect you had a poor crush? If you have the spent grain examine it closely for whole kernels? Post a close up of the spent grain for comments here if you can.

 

[IowaHomeBrewer]

Looks like I have a few things going on here.

So I changed my calculator to use the .08 instead of .2 for absorption rates. Left my starting water amount as is, and that shows I started with a boil volume of 8.18 gallons. With a 60 minute boil that means I had 6.68 gallons of wort at the end.

Using those numbers it puts my efficiency at 60%. I will use some of the advice in this thread to improve that more.

1.) Stir grains when pouring them into bag and before I pull the bag
2.) Get a new bag
3.) Pay really close attention to water volume and extend boil if starting boil volume is above 6.5 gallons (i've also updated my water calculator to reflect for lower grain absorption rates)
4.) I can't really crush finer because I don't have my own mill, I use the one at the brew shop I go to. I'll have to run it through twice.

 

[doug293cz]

I'm using a High Gravity BIAB set up, click here to see.

Just today I ran this recipe:

Amount Fermentable PPG °L Bill %
11 lb American - Pale 2-Row 37 1.8 73.3%
1 lb German - Munich Light 37 6 6.7%
1 lb American - Carapils 33 1.8 6.7%
1 lb British Light Crystal 35 10 6.7%
1 lb Corn Sugar - Dextrose 46 0.5 6.7%

I mashed at 148 for 60 minutes. Mashed out at 180 for 10 minutes.

My water volume was 9.3 gallons for the mash/boil.

I did use pH stabilizer to get pH in the right range.

60 minute boil.

I was hoping to get 70% efficiency off of this setup, and was looking for starting gravity of 1.08.

I just finished about an hour ago and took the gravity reading, it was only 1.05 which means only 40% efficiency. I was shooting for an 8% IPA and I'm going to end up with a hop bomb 5% session IPA, which is fine, just not what I was going for.

I knew BIAB was lower efficiency, but not sure what to do to get it better for next time. Here are some things I'm thinking about doing:

1.) Run all the grain through the mill twice.
2.) Change to 90 minute mash

Any other ideas on how to improve efficiency? I suppose I can just beef up the grain bill to account for it, but at 40% I've got to be doing something wrong. Thanks in advance for any suggestions.

What were your pre-boil and post-boil volumes? You can't calculate efficiency without at least one of those. You also need to know the temperature at which the volumes were measured, so that you can compensate for the thermal expansion/shrinkage of the wort. If you are trying to calculate your efficiency using your target batch size instead of actual volumes, your calculations will be borked.

Finer milling and/or longer mash times can improve your conversion efficiency, if conversion at your current conditions is incomplete. Reducing grain absorption will increase your lauter efficiency. Since mash efficiency is conversion efficiency time lauter efficiency, improving either, or both, will improve your mash efficiency.

Brew on

 

[jekeane]

When I do biab, I use a wilser bag, double crush my grains on my normal mill setting .037-.39 i think, moderately squeeze my bag, and do a 90 minute mash and I am always between 80-85%. I have been as high as 90% The only reason I pay attention to those numbers though is for consistency if I intend to brew it again.

 

[SavaShip]

Any other ideas on how to improve efficiency? I suppose I can just beef up the grain bill to account for it, but at 40% I've got to be doing something wrong. Thanks in advance for any suggestions.

I had the exact same issues that you had my friend. BIAB "should" have been higher efficiency, specially since I was fine grinding the barley. Mine never got over 55% though. I attempted about 8 or 9 times times following some great advice on this forum from many members, but in the end it turned out that it was far too messy, and not very enjoyable to me, and my efficiency was always low.

What I ended up doing was getting a 2nd boil-pot and set it up as a lauter tun with a ball valve and bazooka tube. I manually recirculate my wort from my heated pot to the lauter tun, and back, some day I may get a pump and diffuser to automate that a little more. I get on average 86% now with a lot less water, but I feel your BIAB pain a lot! It works for a lot of people, but I just couldn't get it to work for me, and it was sucking the joy out of brewing for me.

If you decide to keep trying it, please share any insights you discover that made it work for you! Keep Brewing!

 

[TexasWine]

So I changed my calculator to use the .08 instead of .2 for absorption rates. Left my starting water amount as is, and that shows I started with a boil volume of 8.18 gallons. With a 60 minute boil that means I had 6.68 gallons of wort at the end.

Did you measure your volumes? If not, as pointed out above, you can't know what your efficiency was/is.

Also, side note, I wouldn't use the Brewer's Friend recipe editor to figure out your efficiency. Instead, there's a little button that says "Brew It". In the brew session you can enter your various volumes and gravity readings to calculate your efficiencies at the different stages of brew day.

 

[IowaHomeBrewer]

Did you measure your volumes? If not, as pointed out above, you can't know what your efficiency was/is.

Also, side note, I wouldn't use the Brewer's Friend recipe editor to figure out your efficiency. Instead, there's a little button that says "Brew It". In the brew session you can enter your various volumes and gravity readings to calculate your efficiencies at the different stages of brew day.

Well I know what I started with water volume wise. I didn't look exactly at what my post-mash pre-boil volume was, or what my post-boil volume was exactly. I think all I can do is really use math to estimate and go from there.

Obviously if I want to be exact in my measurements/repeat-ability I need to do better at measuring water volumes.

Good tip on the Brew It button, going to play with that now.

Thanks

 

[doug293cz]

Well I know what I started with water volume wise. I didn't look exactly at what my post-mash pre-boil volume was, or what my post-boil volume was exactly. I think all I can do is really use math to estimate and go from there.

Obviously if I want to be exact in my measurements/repeat-ability I need to do better at measuring water volumes.

Good tip on the Brew It button, going to play with that now.

Thanks

The only efficiency that you can calculate from your starting water volume is your conversion efficiency. This is an important factor in mash efficiency, and in order to calculate it, you need an accurate first runnings SG measurement (or just a pre-boil gravity reading if you did not sparge.)

Brew on

 

[Bobby_M]

You should be able to ask for a finer crush at you lhbs. Frankly it's poor service to not give the customer what they want. You can get away with 60 minute mash at 152F or higher but at 148 you need to mash for 90 minutes.

BIAB has an absorption of only .07 gal per pound or even less if you squeeze the bag. I start my boil at 7 gallons and that's usually starting with 7.5g strike.

Nothing wrong with a mash out but you should know your pH before going over 165-170f.

 

[Gavin C]

As others have said. Without volume readings and gravity reading efficiency calculations are impossible.

pH 5.2 stabilizer is worse than useless. (See the common errors in water). It's in the all-grain section. Many of us have fallen victim to this snake oil. (Myself included)

There is a pretty straight forward walk through of efficiency in my signature below. You might find some pointers. It's really very simple. You just need to do two things.

• Collect accurate data
• Use brewing software

You're halfway there.

Mash Efficiency


Brewhouse Efficiency

 

[Ozarks Mountain Brewery]

the reason most people get poor efficiency with bib is not washing enough the sugar off the grain, how ever you brew besides crush thats usually the issue, you can achieve this several ways, the easies way is to dunk sparge in a separate bucket of water then pour that water back in.
the best way is to recirculate with a pump but that introduces a whole number of expenses

 

[Bosh]

When I do biab, I use a wilser bag, double crush my grains on my normal mill setting .037-.39 i think, moderately squeeze my bag, and do a 90 minute mash and I am always between 80-85%. I have been as high as 90% The only reason I pay attention to those numbers though is for consistency if I intend to brew it again.

The squeezing is important. You lose a surprising amount of wort if you don't do that.

My first BIAB I ****ed up the mash temp, used too small of a bag (BIAB bags are bigger than grain steeping bags, who knew?), had too coarse of a crush, spilled some wort on the floor and didn't squeeze and got 48% efficiency.

Fixing stuff like that gets you very nice efficiency even with a very basic stove top set-up.

 

[doug293cz]

the reason most people get poor efficiency with bib is not washing enough the sugar off the grain, how ever you brew besides crush thats usually the issue, you can achieve this several ways, the easies way is to dunk sparge in a separate bucket of water then pour that water back in.
the best way is to recirculate with a pump but that introduces a whole number of expenses

I disagree that "not washing enough the sugar off the grain" is the main reason some people get poor efficiency with BIAB. How much of the converted sugar makes it into the boil kettle is the Lauter Efficiency. It is fairly straight forward to calculate the lauter efficiency for standard BIAB using a full volume mash and no sparge. The lauter efficiency is entirely dependent on the pre-boil volume, grain bill, and apparent grain absorption. If the grain was 100% converted, then mash efficiency would equal the lauter efficiency.

Below is a chart showing Lauter Efficiency vs. Grain Absorption for both a 10 lb and a 15 lb grain bill. It assumes that you use water sufficient to obtain 6.75 gal pre-boil volume (room temp basis), and all wort drained from the bag goes into the BK.



You cannot get lower lauter efficiency with full volume BIAB unless you discard some of the drained wort. Since most BIAB'ers achieve 0.1 gal/lb grain absorption or less, mash efficiencies should be greater than 81% for 10 lb grain bills, and 74% with 15 lb grain bills. If their efficiencies are lower, it is because their mash did not fully convert (not all available starch converted to sugar.) Since we see lots of threads with BIAB brewers complaining about 50% - 60% (or worse) mash efficiencies, we must conclude that the primary problem is lack of complete conversion in the mash (poor conversion efficiency.) Poor conversion efficiency is what can be helped by finer crush, and/or longer mash times.

Also, recirculation does nothing to improve lauter efficiency. It can however improve conversion efficiency by speeding up the conversion process.

Brew on

 

[Ozarks Mountain Brewery]

weather its not enough time or wrong amounts of water it can be many things and your right forgot about that. try chewing on you grain after the mash, is it sweet or not, it shouldn't be at all, mine is so dry with no sweet taste my dog even turns away

 

[FizzerNoob]

That really is the great thing about BIAB, assuming complete conversion, your efficiency will be a constant, which is related directly to grain absorption. You lose the variable of the sparge and lauter. You also avoid the possibility of over sparging and extracting undesirable compounds

 

[Gavin C]

I disagree that "not washing enough the sugar off the grain" is the main reason some people get poor efficiency with BIAB. How much of the converted sugar makes it into the boil kettle is the Lauter Efficiency. It is fairly straight forward to calculate the lauter efficiency for standard BIAB using a full volume mash and no sparge. The lauter efficiency is entirely dependent on the pre-boil volume, grain bill, and apparent grain absorption. If the grain was 100% converted, then mash efficiency would equal the lauter efficiency.

Below is a chart showing Lauter Efficiency vs. Grain Absorption for both a 10 lb and a 15 lb grain bill. It assumes that you use water sufficient to obtain 6.75 gal pre-boil volume (room temp basis), and all wort drained from the bag goes into the BK.

View attachment 300045

You cannot get lower lauter efficiency with full volume BIAB unless you discard some of the drained wort. Since most BIAB'ers achieve 0.1 gal/lb grain absorption or less, mash efficiencies should be greater than 81% for 10 lb grain bills, and 74% with 15 lb grain bills. If their efficiencies are lower, it is because their mash did not fully convert (not all available starch converted to sugar.) Since we see lots of threads with BIAB brewers complaining about 50% - 60% (or worse) mash efficiencies, we must conclude that the primary problem is lack of complete conversion in the mash (poor conversion efficiency.) Poor conversion efficiency is what can be helped by finer crush, and/or longer mash times.

Also, recirculation does nothing to improve lauter efficiency. It can however improve conversion efficiency by speeding up the conversion process.

Brew on

Great stuff Doug. Is this based on your own brews or a clever mathematical model you put together. Either way, thanks for sharing it.

Your graph rings very true for my setup. I'm right over to the left at 0.045gallons/pound absorption and typically see 85+ % mash efficiencies for ~10-12lb grain bills.

Full-volume no sparge.

 

[doug293cz]

Great stuff Doug. Is this based on your own brews or a clever mathematical model you put together. Either way, thanks for sharing it.

Your graph rings very true for my setup. I'm right over to the left at 0.045gallons/pound absorption and typically see 85+ % mash efficiencies for ~10-12lb grain bills.

Full-volume no sparge.

It's a mathematical model that just does a mass balance on the sugar and water in the mash, assuming the sugar is uniformly distributed in the available wort/water (which will be valid unless the mashing process is really borked.) Batch sparging is a deterministic process, and no-sparge is a subset of batch sparging as far as lautering is concerned. This is essentially the same type of model that Kai Troester put together here. I built my own model from scratch so that I could better understand how everything fit together, and what interacted with what.

Thanks for the data point that helps validate the model.

Brew on

 

[Bosh]

Since most BIAB'ers achieve 0.1 gal/lb grain absorption or less...

Most, yeah, but I think some of the people with low BIAB efficiency are precisely the people who AREN'T getting absorption that low. I know I didn't my first time.

 

[doug293cz]

Most, yeah, but I think some of the people with low BIAB efficiency are precisely the people who AREN'T getting absorption that low. I know I didn't my first time.

But even with grain absorptions of 0.15 gal/lb, efficiencies in the low to mid seventies are achievable if conversion efficiency is good. So, conversion efficiency is usually a big part of the problem (if not all of the problem.)

Brew on

 

[The_Bishop]

The last brew I did was BIAB. I know it's common wisdom to grush the grains to near flour, and my mill gap is tight (.032). What I did with my last brew, and will continue to do, is condition the grain prior to milling. While you theoretically cannot get a stuck sparge with BIAB, I did notice that the grain drained much easier with the large quantity of intact husks.

 

[FizzerNoob]

Is anyone using malt conditioning prior to crush for BIAB? I've always preferred it when fly sparging.

 

[The_Bishop]

I am, see the post directly above yours.

 

[Psylocide]

I "crush" with a blender to near-powder.

Always interesting to see people say "BIAB nets lower efficiency."

Where did that start?

 

[1977Brewer]

I "crush" with a blender to near-powder.



Always interesting to see people say "BIAB nets lower efficiency."



Where did that start?

Probably someone who totally screwed their efficiency by not crushing fine enough. I'm basically milling my grain to flour now, and I've been overshooting my target gravities by ten points. No idea what it works out to efficiency wise because I stopped trying to figure it out.