Very low efficiency?

[Lynchy217]

Hi, I just brewed an IPA with 10 pounds of 2 row and 1 pound of crystal 20L. My measured OG was 1.040, which calculates to a brewhouse efficiency of 49%.. I've been brewing on this system for a little while, and always noticed that the gravity was a bit lower than expected, but I didn't calculate efficiency until recently. This seems abysmal

What could I be doing wrong? My temperature post dough-in was 149F, and my starting volume was 8 gallons. I do squeeze the **** out of the bag when I'm done mash to get all the sugars I can. Do I need to sparge my BIAB after, maybe? or is there a problem with how I'm doing mash? I have an electric kettle with a steamer basket that the bag fits i perfectly. I know I hear about non-BIAB people talking about mash thickness. Is this what's killing me? should I set some water aside to have a thicker mash and a sparge after?

Any tips you guys can provide to increase the efficiency of my BIAB process would be great.

 

[Norselord]

What is your water volume measurement at various points in your process?

Strike
Sparge
Pre-Boil
Post-Boil

etc.

 

[Lynchy217]

I don't sparge. When I first started with BIAB, I read on here that you don't need to sparge. Maybe this is my problem.

So to answer your question:
Strike: 8 gallons
Sparge: 0 gallons
Pre-boil: 8 gallons minus what ever is absorbed by the grain. I think this is less than .25 gallons.
Post-boil: 5.5 gallons.

 

[audioa84]

I am a fellow BIAB'er and I consistently get in the 70's range. I also squeeze the daylights out of the bag like you. I brew in a 15g kettle using induction so I would think our experiences should be somewhat similar. I typically start with 7.5-7.75 gallons of strike water so I wouldn't think mash thickness is the issue. Do you ever find doughballs? Also, what are you using for measurement? Have you calibrated it lately?

 

[Lynchy217]

I never have issues with doughballs. I'm really careful to mix the grain in as I pour. Which measurement are you questioning? I use my old bucket fermentor to measure out the water, and I use one of these for gravity, so there isn't much of a calibration that can be done.

 

[soccerdad]

How long do you mash? Who crushes your grain .. you or the seller?

 

[audioa84]

I was referring to measuring your gravity. You can't necessarily change the paper on the inside of the hydrometer but a brewing podcast I was listening to this week mentioned that they had experienced the paper moving in their hydrometer and that was why they were measuring off. Hydrometers are easy to check. Take some distilled water and see what the gravity reading is. It should be 1.000 at room temp.

Here is an article on checking a hydrometer: https://byo.com/mead/item/411-calibrate-your-hydrometer-and-fermenter-techniques

The hydrometer being off is a long shot but should be checked. Do you do any recirculation or stirring during the mash? I'm wondering about the water under and around the basket. I don't know of much more to check but do suggest you try changing different variables and see what happens.

 

[Lynchy217]

How long do you mash? Who crushes your grain .. you or the seller?

I crush it myself. The crush seems fine to me, though. I've never seen an intact grain of barley with the current width. I could try a finer crush, but it seems pretty good to me.

 

[Lynchy217]

I was referring to measuring your gravity.

Hmm, interesting. I'll pick up some distilled water tomorrow and test. Thanks for the tip!

 

[soccerdad]

If satisfied with crush, you may want to try extending mash time. The guys from 'down under' often say that 3 vessel brewers mash for 60 and their sparge might take another 30. The idea is to fully saturate the grain in order to extract the sugars .. not fully saturated= not fully extracted. I tend to get my target gravity in 60 min, but my crush *might* be finer than yours. Even still, after 60, I go clean something or take care of something else in the process for 15 or 20 minutes... gets me 75% plus most days.

 

[Lynchy217]

Interesting. I do mash for 60 mins. I'll look into trying for a longer time next time. I'll be brewing again next weekend, and I'm hoping to get this figured out for then.

 

[madscientist451]

You have a few options:
-Run your grain through your mill twice
-Dunk the bag up and down in the pot to get the water moving through the grain
-Get a kettle with a spigot and manually recirculate for about 5-10 minutes at the end of the mash.
-Adjust your recipes by adding more grain and don't worry about efficiency
-since you have a steamer basket, pull it out, figure a way to suspend the basket over a bucket and pour the wort over the grain, basically another way to manually recirculate.

 

[fun4stuff]

I had a jump in efficiency when I started controlling water chemistry/mash pH.

I got another boost when I started squeezing the living day lights out of my bag with a my homemade bag press...

I also usually mash for 90 mins or longer. Not sure if it's necessary... I just usually have other things going on.

 

[RM-MN]

How well the grain is crush is one of the determining factors in how long you need to mash. I get full conversion in 20 minutes or less because my grain is milled really fine. Another brewer may need 60 minutes or longer. The water you mash with must reach the center of every particle of grain in order for the starch to be gelatinized and then converted to sugar. Then the sugar must be able to get back out of that grain particle. I've seen an article where the maltster was able to get good efficiency with uncrushed grain but it didn't say how long that took. The quality of the milling is the biggest factor by far in determining how good efficiency you will get. You can compensate a bit for a poor crush by extending the mash to 90 or even 120 minutes but then you have to worry about heat loss too.

Try setting your mill closer so your grains get crushed finer. If that doesn't change the efficiency you get we can dig deeper.

 

[tr08]

Try thinner mash.

 

[Oginme]

I am guessing that you do a full volume BIAB.

The first through fifth recommendation is to grind your grain finer. With BIAB, you don't need to worry about a stuck sparge. Check it to make sure you don't have full, uncracked kernels.

Next, when you dough in, stir your mash for about 5 to 10 minutes to ensure that you don't have any dough balls. When I say stir, I mean mix it like you are a human blender.

After that, get a pH meter and check your mash pH. While I have found that crushed grains in water tends to work its way to an acceptable pH over time, starting out in the right range of 5.2 to 5.6 will maximize the enzyme efficiency.

 

[wilserbrewer]

Is your basket considerably smaller than your kettle? How much space is below the basket to the bottom of the kettle?

How much space is on each side of the basket?

If your basket is undersized, you may be effectively mashing in only a portion of the water. ?

You could try raising and draining the basket several times to mix all the water through the grain prior to grain removal.

Or better yet ditch the basket.

And crush of course?

 

[crunch1224]

Without knowing your equipment, water profile and PH we can only (guess).

 

[Syke]

I don't sparge. When I first started with BIAB, I read on here that you don't need to sparge. Maybe this is my problem.

So to answer your question:
Strike: 8 gallons
Sparge: 0 gallons
Pre-boil: 8 gallons minus what ever is absorbed by the grain. I think this is less than .25 gallons.
Post-boil: 5.5 gallons.

You don't need to sparge, but it is a great way to increase efficiency.

 

[doug293cz]

Hi, I just brewed an IPA with 10 pounds of 2 row and 1 pound of crystal 20L. My measured OG was 1.040, which calculates to a brewhouse efficiency of 49%.. I've been brewing on this system for a little while, and always noticed that the gravity was a bit lower than expected, but I didn't calculate efficiency until recently. This seems abysmal

What could I be doing wrong? My temperature post dough-in was 149F, and my starting volume was 8 gallons. I do squeeze the **** out of the bag when I'm done mash to get all the sugars I can. Do I need to sparge my BIAB after, maybe? or is there a problem with how I'm doing mash? I have an electric kettle with a steamer basket that the bag fits i perfectly. I know I hear about non-BIAB people talking about mash thickness. Is this what's killing me? should I set some water aside to have a thicker mash and a sparge after?

Any tips you guys can provide to increase the efficiency of my BIAB process would be great.

I don't sparge. When I first started with BIAB, I read on here that you don't need to sparge. Maybe this is my problem.

So to answer your question:
Strike: 8 gallons
Sparge: 0 gallons
Pre-boil: 8 gallons minus what ever is absorbed by the grain. I think this is less than .25 gallons.
Post-boil: 5.5 gallons.

I have a mash/lauter simulator, so I played around with your numbers and came to the following conclusions:

• A grain absorption of only 0.25 gal with 11 lbs of grain would require a grain absorption rate of 0.023 gal/lb. The lowest believable rate I have ever seen is 0.05 gal/lb, so your assumed grain absorption is almost certainly too low. Rather than using your assumed grain absorption, I used a rate of 0.07 gal/lb for the simulation. This is a good value for a reasonably aggressive squeeze.
• Using a 0.07 gal/lb absorption rate, your pre-boil volume would have been 7.23 gal, and your total boil off to hit 5.5 gal post-boil would have been 1.73 gal. This is a very high boil off percentage (24%.) Conventional wisdom says boil off should be less than 15%, and some brewers are recommending less than 10%.
• For 5.5 gal post-boil @ 1.040 OG, that works backwards to 1.030 pre-boil SG for 7.23 gal. And with 11 lbs of grain @ an assumed dry basis potential of 37 pts/lb (35.5 pts/lb as-is with included moisture) that works out to a mash efficiency of only 56% (not sure how you calculated your 49%.)
• If we assume your lauter efficiency is the max theoretical for a no sparge with 11 lbs of grain, 8 gal of strike water, and 7.23 gal pre-boil, then your lauter efficiency would have been 85%. Since mash efficiency equals conversion efficiency times lauter efficiency, or alternatively conversion efficiency equals mash efficiency divided by lauter efficiency, your conversion efficiency would only have been 66%. This is dismal conversion efficiency, as BIAB can easily achieve 95%, or better.

Discussion:

The steamer basket could very well have reduced your lauter efficiency from the theoretical max (which would also make your conversion efficiency higher than calculated above, but still way low.) This is because the wort outside and under the basket is likely to be lower SG than the wort in the grain bed itself, since wort mixing between inside and outside the basket is limited. If the wort in the grain bed in the basket is higher in sugar concentration (higher SG), then more sugar will be retained in the drained grain than if the wort sugar concentration was uniform throughout the entire volume. The more sugar retained in the grain, the lower your lauter eff. This is one reason to ditch the basket.

As many have said already, the main cause of low conversion efficiency is too coarse a grain crush, and another factor is mash pH out of range (less than 5.2 or greater than 5.6.) First thing to address is crush.

The basket could also be hurting your conversion efficiency. It has been shown that thinner mashes convert faster than thicker mashes, and thus can improve conversion efficiency in time limited mashes. With the basket your effective mash thickness is really the volume of strike water within the basket divided by the total grain weight, as the water outside the basket isn't really available to hydrate the grits, or provide increased enzyme mobility. The effect of the basket is to make your mash thicker. This is another reason to ditch the basket.

You can actually measure your conversion efficiency just by knowing your grain bill weight, strike water volume, and the SG of the wort in the mash by using the method here. Since your biggest efficiency detractor appears to be your conversion efficiency, you should start measuring that directly, and using those results to determine the effectiveness of any process changes you make .

Hopefully this gives you some additional information you can use to improve your efficiency going forward.

Brew on

 

[Lynchy217]

Hi all, Figured I'd check in. First off, my Hydrometer is fine, so that wasn't the problem. For my next brew, I will try a finer grind on my grain, and I'll take some ph measurements to see where I sit there.

Unfortunately, I can't really ditch the steamer basket, because my heating elements are on the bottom of the kettle, and if the bag rests against them, it will burn. Eventually, I do want to recirculate from the bottom of the kettle to the top. I already have a pump to do this with, but I would have to modify the kettle, so I've been putting it off. Maybe this efficiency problem with spur me to do so sooner if it's part of my issue, though.

For now, I'm hoping that between the ph adjustments and the finer crush I'll be able to achieve a decent efficiency and I can work on increasing it from there.

 

[doug293cz]

Hi all, Figured I'd check in. First off, my Hydrometer is fine, so that wasn't the problem. For my next brew, I will try a finer grind on my grain, and I'll take some ph measurements to see where I sit there.

Unfortunately, I can't really ditch the steamer basket, because my heating elements are on the bottom of the kettle, and if the bag rests against them, it will burn. Eventually, I do want to recirculate from the bottom of the kettle to the top. I already have a pump to do this with, but I would have to modify the kettle, so I've been putting it off. Maybe this efficiency problem with spur me to do so sooner if it's part of my issue, though.

For now, I'm hoping that between the ph adjustments and the finer crush I'll be able to achieve a decent efficiency and I can work on increasing it from there.

If your kettle is well insulated during the mash, and you are not doing step mashes, there really is no reason you would need to fire the element while the bag is in the kettle. Losing a few degrees during the mash is no biggie. I typically lose 3 - 4 degrees during the mash (and got a first place ribbon out of it.) If you absolutely have to apply heat for some reason, just lift the bag enough to clear the element while heating.

Brew on

 

[Lynchy217]

Sure, but if I base my setup on not using the heater elements, then I won't be able to do step mashes moving forward (which is something I would like to experiment with eventually). I would rather just set up the circulating pump to pull wort from the bottom of the kettle (below the basket) to the top (into the basket). This should solve the problem of mixing while allowing me to experiment with other mash techniques later if I want. I suppose in the mean time, I can turn everything off and wrap a towel around the kettle, though..

 

[violinguy]

Mash temp control is one of the only things I have going for me with BIAB so far lol. I lost only 2 degrees in 60 minutes yesterday using my old heavy parka to wrap around the kettle.

My question going forward is this; I've kept careful track of water volume, mash temp, and collecting the drips from my strainer. Yesterday I got 67% and I sparged by pouring 170 degree water over the grains in a large colander over the pot. Would it be safe to say that I could get my efficiency up to or over 70% by doing the following:

-Better ph contol - my water is between 7.5 and 8
-Double crush grains

Anything else I can do to increase efficiency? I don't want to use more grain if I can avoid it. Thanks!

 

[doug293cz]

Sure, but if I base my setup on not using the heater elements, then I won't be able to do step mashes moving forward (which is something I would like to experiment with eventually). I would rather just set up the circulating pump to pull wort from the bottom of the kettle (below the basket) to the top (into the basket). This should solve the problem of mixing while allowing me to experiment with other mash techniques later if I want. I suppose in the mean time, I can turn everything off and wrap a towel around the kettle, though..

Yeah, once you go recirculation, then the basket is no issue. My basic BIAB recommendations are always:

• No recirculation -- no basket
• Recirculation -- basket or false bottom/bottom rack

Brew on

 

[Lynchy217]

Yeah, once you go recirculation, then the basket is no issue. My basic BIAB recommendations are always:

• No recirculation -- no basket
• Recirculation -- basket or false bottom/bottom rack

Brew on

Cool, I think I'll go for the second option, since that is a move towards my eventual long-term setup. Thanks for the info.

 

[wilserbrewer]

Cool, I think I'll go for the second option, since that is a move towards my eventual long-term setup. Thanks for the info.

Good luck with your eventual long term plan, but sincerely your immediate future looks bleak unless your using temp control with recirculation along with the basket.

 

[fun4stuff]

Mash temp control is one of the only things I have going for me with BIAB so far lol. I lost only 2 degrees in 60 minutes yesterday using my old heavy parka to wrap around the kettle.

My question going forward is this; I've kept careful track of water volume, mash temp, and collecting the drips from my strainer. Yesterday I got 67% and I sparged by pouring 170 degree water over the grains in a large colander over the pot. Would it be safe to say that I could get my efficiency up to or over 70% by doing the following:

-Better ph contol - my water is between 7.5 and 8
-Double crush grains

Anything else I can do to increase efficiency? I don't want to use more grain if I can avoid it. Thanks!

Head over to the brew science section and you can get some really in depth info on pH control... But don't let them scare you way. Maybe instead, first, download bru'n water excel spread sheet and read through that.

It's the mash ph that matters- not so much water pH.

So then your first choice will be do you want to use your own water or RO water. Your own water would require getting a water report (from Bard Labs or the city's website) to figure out mineral composition which you type into bru'n water. If you go this route, you'll need to get rid of chlorine if present. If you start with RO water, then you can assume mineral content is near zero (bru'n water has a setting for RO water).

Your next step is to choose a target water profile (bru'n water has these).

You then enter in your grains to bru'n water and through trial and error figure out how much of which minerals you need to add to your water to hit your target profile.

It will then tell you predicted mash pH. If it's higher then 5.6, you'll want to add some acid (e.g. Lactic acid) and you figure how much through trial and error in the spreadsheet until it's somewhere between 5.2-5.6. If it's predicted to be lower than 5.2, then you add a base (e.g. Pickling lime).

Other tips: I think there are youtube vids explaining how to use bru'n water. Brewersfriend also has a water chemistry calculator, which I sometimes I find is more accurate than bru n water... But I suspect it's about 50/50. Haven't done enough comparisons yet. Post your plan to brew science before you go through with it to make sure you've done everything correctly your first go around.

The other thing that helped me was squeezing the bag better. I nest 3 five gallon buckets together, with multiple holes drilled in the sides and bottom of the middle. Grain bag goes in middle bucket. Press bag with top bucket and liquid falls into bottom bucket. I routinely get 0.03-0.05 gal/absorption.

 

[jan_b19]

stir stir stir and stir some more

you need to recirculate the water in the mash through your grains to get all of the converted starch in your wort.

 

[Lynchy217]

Hi all, I just brewed again, and I figured I'd post results of my attempted fixes. The differences between this brew and the last one are a decreased roller spacing on my mill and recirculating from below the strainer basket into the top of the kettle during mash. I did take a ph reading, but I didn't attempt to correct it. Interestingly, the wort was actually too acidic, coming in at ~4.5. I know my pales will be a bit less acidic than this stout, but I was surprised at how low the reading was. I used test strips, so I'm not sure how accurate that is, but it is an interesting result, and certainly one I'm going to keep an eye on and act on next time.

I used the following grain bill:

8# 2 Row
1# Chocolate Malt
1# Cara 80L
0.5# Flaked Oats
1# Lactose

with 5.5 gallons of wort and an OG of 1.054, that comes out to ~70% efficiency, which is a great jump for this system. I'll keep improving it, and I plan to tackle the water chemistry issue soon. One thing to note.. I don't know what the spacing on my rollers is at the moment, I just know it's smaller than it was. Out of curiosity, what spacing do you guys use in your mills?

Thanks to everyone who posted in this thread. I'm very happy with the improvements these simple changes provided. I'll continue to work on it from here, but I'm content with a 70% efficiency as a starting point for tuning my system. You guys rock!

 

[doug293cz]

To measure your roller spacing, get a set of feeler gauges from an automotive supply store. I currently have my two roll mill set at a 0.022" gap for BIAB, and get 95% - 100% conversion efficiency. By squeezing to a 0.05 gal/lb grain absorption, I get about 83% mash efficiency.

Brew on

 

[fun4stuff]

Hi all, I just brewed again, and I figured I'd post results of my attempted fixes. The differences between this brew and the last one are a decreased roller spacing on my mill and recirculating from below the strainer basket into the top of the kettle during mash. I did take a ph reading, but I didn't attempt to correct it. Interestingly, the wort was actually too acidic, coming in at ~4.5. I know my pales will be a bit less acidic than this stout, but I was surprised at how low the reading was. I used test strips, so I'm not sure how accurate that is, but it is an interesting result, and certainly one I'm going to keep an eye on and act on next time.

I used the following grain bill:

8# 2 Row
1# Chocolate Malt
1# Cara 80L
0.5# Flaked Oats
1# Lactose

with 5.5 gallons of wort and an OG of 1.054, that comes out to ~70% efficiency, which is a great jump for this system. I'll keep improving it, and I plan to tackle the water chemistry issue soon. One thing to note.. I don't know what the spacing on my rollers is at the moment, I just know it's smaller than it was. Out of curiosity, what spacing do you guys use in your mills?

Thanks to everyone who posted in this thread. I'm very happy with the improvements these simple changes provided. I'll continue to work on it from here, but I'm content with a 70% efficiency as a starting point for tuning my system. You guys rock!

That's a low pH. Did you add any acid or minerals to the water? When and how did you measure the pH?

 

[Lynchy217]

That's a low pH. Did you add any acid or minerals to the water? When and how did you measure the pH?

I did not add anything to the water. I started my mash and stirred for 5 mins or so. I then took a small sample, cooled it in a salt bath until it was ~72 degrees. Then I put the strip in the solution for 2 seconds, as suggested on the packaging and compared the color to the scale provided. It seemed pretty straight forward. I tested a second strip after with identical results.

 

[RM-MN]

There have been reports about the accuracy of the test strips. As I read it most aren't worth the paper they are printed on.

 

[fun4stuff]

I did not add anything to the water. I started my mash and stirred for 5 mins or so. I then took a small sample, cooled it in a salt bath until it was ~72 degrees. Then I put the strip in the solution for 2 seconds, as suggested on the packaging and compared the color to the scale provided. It seemed pretty straight forward. I tested a second strip after with identical results.

It seems like an oddly low ph for that grain bill, which makes me doubt the test strips. Most of the water geeks in the brew science forum will recommend $100-200+ ph meters, which are definitely a better meter (particularly if your working lab), but I don't think they're necessary for everyone. I have had good luck with a meter I got for less than $15 from Amazon (I just went by reviews). You could always just go with RO water and use either the bru n' water excel sheet or brewers friend water chemistry calculator. I have found them both accurate to the tenth decimal place of ph (most of the time).

 

[Lynchy217]

I just ordered a MW 102 to test my next batch with.. I was able to confirm that the strips are garbage when I tested distilled water with them and they read 4.7..... Tossed the bottle. I am excited to have decent equipment to test ph with, though.