Low Mash Efficiency

[APipeDream]

Brewed 10 gallons of a Russian River Row-2 Hill 56 clone last night with a buddy. We were hoping for 1.055 OG, but only got to 1.049. This is our second all-grain brew, and based on our steps I *thought* we would have better efficiency. Can I please get a quick gut-check on our process?

We heated 11 gallons of water to 163 degrees, then added 14lbs of American 2-Row, 5lbs Maris Otter, and 2lbs Crystal 20L. Stirred for a minute or two until some foam started forming, then turned off the heat and covered the pot for 60 minutes (the temp was 156 when I closed the pot). We managed to sparge 8 gallons of wort in the initial drain, then another 4 from about 6 gallons of 155 degree water added for a second sparge. Boiled for 90 minutes.

This is only our 4th all-grain brew, and the first couple we really hadn't done our homework, so our fault there. This one though, I honestly expected a better OG from, but according to the calculators we only achieved about 64%.

 

[specharka]

Batch sparging typically doesn't yield a very high lauter efficiency. You will get diminishing returns on each successive charge of sparge water.

If you are looking for better brewhouse efficiency, switch to a fly sparging method. Might require an additional HLT but it is the single best brewhouse upgrade for an all grain brewer. Otherwise, your grain additions should target a more modest 60% efficiency. A mash efficiency of 64% is actually on the high side for a batch sparge.

Not to toot my own horn, but my fly sparging method routinely achieves 80% mash to kettle.

 

[pricelessbrewing]

Batch sparging typically doesn't yield a very high lauter efficiency. You will get diminishing returns on each successive charge of sparge water.

If you are looking for better brewhouse efficiency, switch to a fly sparging method. Might require an additional HLT but it is the single best brewhouse upgrade for an all grain brewer. Otherwise, your grain additions should target a more modest 60% efficiency. A mash efficiency of 64% is actually on the high side for a batch sparge.

Not to toot my own horn, but my fly sparging method routinely achieves 80% mash to kettle.

Ehhh not necessarily. Equal runnings batch sparging can easily get you 80% lauter efficiency and mash efficiency of ~75% with very minimal effort or time. I would never trade that for a long fly sparge to gain an extra 5% lauter efficiency. Where did you get the idea that a batch sparge can only get a 60-65% mash efficiency?

 

[Rcbandl]

Ehhh not necessarily. Equal runnings batch sparging can easily get you 80% lauter efficiency and mash efficiency of ~75% with very minimal effort or time. I would never trade that for a long fly sparge to gain an extra 5% lauter efficiency. Where did you get the idea that a batch sparge can only get a 60-65% mash efficiency?

I have to agree. with the proper technique, batch sparging can almost run side by side with fly.

 

[Biscuits]

Only thing I see is that your sparge water should have been @ 170* but that wouldn't have necessarily helped your efficiency. Honestly, 64% efficiency isn't horrible, I'd say see what your next few brews yield and if it is 64%, then it is 64%, adjust fire as needed.

 

[DogSlobber]

Do you know how much the temp dropped during the mash? It sounds like you were using a direct fire mash tun which was probably uninsulated? You may have ended up 5-10 deg under your starting temp over an hour. Sparging with 155 would not have been enough to heat things up at the end so you would have higher viscosity wort that would be harder to free from the grains. When I moved to a mash ton with a false bottom, two things helped improve my efficiency drastically while batch sparging. The first was a final mash out infusion to bring the mash temp up to 168-170. The second was to drain more slowly. These combined brought me up into the low-mid 70s. I have since picked up another 10 points by recirculating during the mash. Good luck!

 

[RM-MN]

Only thing I see is that your sparge water should have been @ 170* but that wouldn't have necessarily helped your efficiency. Honestly, 64% efficiency isn't horrible, I'd say see what your next few brews yield and if it is 64%, then it is 64%, adjust fire as needed.

People have experimented with hot water and cold water for the batch sparge with almost no difference in the amount of sugars recovered. Instead of worrying about the sparge temperature you need to be mostly concerned with the quality of the milling of the grain since that seems to be nearly always the cause of low efficiency. You can compensate somewhat for poorly milled grains by mashing longer if you can control the temperature but there seems to be a limit to the gain from even a long mash.

I've been milling my own grain very fine which I can work with since I do the BIAB mash and typically get 85% or more efficiency with even a 20 minute mash and a small amount of sparge.

 

[xben]

People have experimented with hot water and cold water for the batch sparge with almost no difference in the amount of sugars recovered. Instead of worrying about the sparge temperature you need to be mostly concerned with the quality of the milling of the grain since that seems to be nearly always the cause of low efficiency. You can compensate somewhat for poorly milled grains by mashing longer if you can control the temperature but there seems to be a limit to the gain from even a long mash.

I've been milling my own grain very fine which I can work with since I do the BIAB mash and typically get 85% or more efficiency with even a 20 minute mash and a small amount of sparge.

I did the same few months ago and my mash efficiency jumped to 85%! I condition my malt and grind as fine as I can to keep the husks. I never had any stuck problem or tannin flavors etc etc..

 

[RM-MN]

I did the same few months ago and my mash efficiency jumped to 85%! I condition my malt and grind as fine as I can to keep the husks. I never had any stuck problem or tannin flavors etc etc..

Isn't amazing that you can avoid tannins by keeping the wort at a proper pH and still grind those husks to powder? Why, you can even boil the mash without extracting tannins if you keep the pH where it should be.:rockin:

 

[APipeDream]

Thank you all for the feedback. I was a little skeptical about the 64% being "on the high side" comment, so thanks for confirming that shouldn't matter. From your comments, I it would seem that the temp when I began the mash and/or quality of grain was the issue. We have a "standard" bayou classic 15 gallon pot for mashing, not insulated. I read a few comments in searching the thread that it might help if I wrapped the pot in towels during the rest, which I can't see hurting things.

So should I ensure the temp of the mash is ~170 before closing the lid and starting the rest? I'm just trying to understand if the temp should remain that high as long as possible or not. I thought I should be ending around 150-155. I can move the pot to very low flame that can keep it where I need to for a longer period of time.

 

[ba-brewer]

Sparging with 155 would not have been enough to heat things up at the end so you would have higher viscosity wort that would be harder to free from the grains. When I moved to a mash ton with a false bottom, two things helped improve my efficiency drastically while batch sparging. The first was a final mash out infusion to bring the mash temp up to 168-170. The second was to drain more slowly. These combined brought me up into the low-mid 70s. I have since picked up another 10 points by recirculating during the mash. Good luck!

I had a similar experience where a tweak here and there and doing a mash out step seemed to help me get my brewhouse efficiency in the mid 70s. I then started conditioning my grain to help with slow sparges but did not adjust my grind finer and my efficiency dropped back to the mid 60s. Turns out because I dont stir my mash while it rests it takes a bit longer to finish conversion. When my efficiency improved by doing a mash out it was not really improving from the hotter water it was because I was just doing a longer rest. I now check my gravity with a refractometer during the mash to determine when to end my rest and my efficiency is back in the mid 70s without a mash out step. I seemed to have lost a little body in my beers though so I will need to make an adjustment in my starting temp to compensate.


@OP, Calculate your expected gravity of the initial mash and check the gravity of the wort as your mash progresses to determine when the conversion is over that will help you get your efficiency up.

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

 

[RM-MN]

Thank you all for the feedback. I was a little skeptical about the 64% being "on the high side" comment, so thanks for confirming that shouldn't matter. From your comments, I it would seem that the temp when I began the mash and/or quality of grain was the issue. We have a "standard" bayou classic 15 gallon pot for mashing, not insulated. I read a few comments in searching the thread that it might help if I wrapped the pot in towels during the rest, which I can't see hurting things.

So should I ensure the temp of the mash is ~170 before closing the lid and starting the rest? I'm just trying to understand if the temp should remain that high as long as possible or not. I thought I should be ending around 150-155. I can move the pot to very low flame that can keep it where I need to for a longer period of time.

If you mash at 170 your mash will be done in less than 10 minutes because all the enzymes will be dead. You want the mash to be between 148 (very dry beer) and 160 (very malty beer) with a good average range of 152 to 154. Please don't try to mash at 170.

 

[doug293cz]

Brewed 10 gallons of a Russian River Row-2 Hill 56 clone last night with a buddy. We were hoping for 1.055 OG, but only got to 1.049. This is our second all-grain brew, and based on our steps I *thought* we would have better efficiency. Can I please get a quick gut-check on our process?

We heated 11 gallons of water to 163 degrees, then added 14lbs of American 2-Row, 5lbs Maris Otter, and 2lbs Crystal 20L. Stirred for a minute or two until some foam started forming, then turned off the heat and covered the pot for 60 minutes (the temp was 156 when I closed the pot). We managed to sparge 8 gallons of wort in the initial drain, then another 4 from about 6 gallons of 155 degree water added for a second sparge. Boiled for 90 minutes.

This is only our 4th all-grain brew, and the first couple we really hadn't done our homework, so our fault there. This one though, I honestly expected a better OG from, but according to the calculators we only achieved about 64%.

Your biggest efficiency detractor appears to be low conversion efficiency.

Mash Efficiency = Conversion Efficiency * Lauter Efficiency​

For batch sparging, lauter efficiency is not too difficult to simulate given the grain bill, strike and sparge water volumes, grain absorption, and MLT undrainable volume. Using the numbers you provided in my sparge simulator, you should have a lauter efficiency of about 82.5% - 83.5%. If your conversion efficiency were close to 100% then your mash efficiency would have been greater than 80%. But instead, your conversion efficiency works out to about 78% - 79%.

So, you need to work on your conversion efficiency. Factors that affect conversion efficiency are:

• Temperature: Conversion rate is faster at higher temperatures. However, if the temps are too high, then the amylase enzymes get denatured (stop working), and conversion stops. Beta amylase gets denatured at lower temperatures than alpha amylase. Beta denatures rapidly above 150°F, and alpha above 162°F. So going to higher temps is not a good strategy for improving conversion efficiency.
• Time: Longer times allow more conversion to complete, as long as there are starch and amylase enzymes available.
• Crush Size: Smaller particles convert faster than larger particles because of diffusion effects. You can compensate for coarser crush by mashing for longer times.
• Mash Thickness (water to grain ratio): Thinner mashes (more water) convert faster than thicker mashes, so will complete faster. Thicker mashes need more time to achieve the same level of conversion as thinner mashes, all else being equal.
• pH: If pH is too high or too low, then conversion rates can slow down, and max achievable conversion can also be decreased. Keep your mash pH in the 5.2 to 5.7 range for best results.
• Agitation: Agitation (frequent stirring or recirculation) can short circuit some of the diffusion limited processes, and speed up the conversion process.
• Dough Balls: Clumps of non-wetted grain in the mash will not convert, so it is essential to make sure that all the grain clumps are broken up during dough in.

Your mash temp is not low (unless your mash finished below about 146°F), nor is your mash thickness high (you're at 2.1 qt/lb), so the most likely culprit (as noted by previous responders) is too coarse a crush for the mash time allowed. Look into crushing finer and/or mashing longer. Also, make sure you are ok as far as the other factors for conversion efficiency are concerned. In cases of incomplete conversion, a mash out step can provide a short "turbo boost" to the conversion, and gain some efficiency, although getting complete conversion during the initial mash time is preferred.

You might also want to make sure that your batch sparge techniques are adequate, as your lauter efficiency could be less than ideal if proper techniques are not followed.

• Stir the mash well prior to vorlauf and initial run-off. You want to make sure the wort has a uniform sugar concentration for maximum efficiency.
• Stir for about 5 minutes after sparge water addition. You want to maximize the sugar pick-up of the sparge water prior to draining.
• Make sure you allow the MLT to drain completely after each run-off. The more wort left in the MLT after each run-off, the lower your efficiency.
• Minimize the undrainable (dead) volume of your MLT. Again, any wort left in the MLT reduces efficiency.
• Adjusting strike vs. sparge water volumes to get equal initial and sparge run-off volumes can provide 0.5% - 1% additional lauter efficiency points. (For your case it would provide 0.6% - 0.7% improvement.)

Run-off rate does not affect efficiency when batch sparging, so drain as fast as your MLT will allow.

Also, your terminology is a little off. The first 8 gal you obtained from the mash is your first runnings, not sparged volume. Sparging is adding fresh water to the mash in order to rinse additional sugar from the grain, so only second (and subsequent) runnings are sparged volume. Finally, when batch sparging, the recovered wort volume should equal the amount of sparge water added, as the grain is saturated after initial run-off, and will not absorb additional water during the sparge. If you get less wort than sparge water used, you are not draining the MLT well enough after the sparge step.

Brew on

 

[doug293cz]

Do you know how much the temp dropped during the mash? It sounds like you were using a direct fire mash tun which was probably uninsulated? You may have ended up 5-10 deg under your starting temp over an hour. Sparging with 155 would not have been enough to heat things up at the end so you would have higher viscosity wort that would be harder to free from the grains. When I moved to a mash ton with a false bottom, two things helped improve my efficiency drastically while batch sparging. The first was a final mash out infusion to bring the mash temp up to 168-170. The second was to drain more slowly. These combined brought me up into the low-mid 70s. I have since picked up another 10 points by recirculating during the mash. Good luck!

Everything you did to improve your efficiency got you better conversion efficiency, basically by extending the mash time and increasing the temp (which speeds up conversion until denaturing is complete.) This indicates that your mash conditions did not provide anywhere near complete starch conversion.

Higher temps to reduce viscosity and improve run-off is a non-issue. A thinner mash will provide lower viscosity, and improve your saccharification rate as well. See my post here: https://www.homebrewtalk.com/showpost.php?p=7159688&postcount=11

Brew on

 

[stpug]

Brewed 10 gallons of [beer]. We heated 11 gallons of water, added 21lbs of [grain]. Stirred, turned off heat, and mashed for 60 minutes. We drained 8 gallons of wort in the initial drain, then another 4 from 6 gallons of [sparge] water. Boiled for 90 minutes.

21*0.125=2.625 gallons loss due to grain absorption
11-2.625=8.375 gallons
---you got 8 so you must have baout 0.375 gallon deadspace. That checks out pretty good.

Added 6 gallons sparge water and drained 4 gallons. That's not good. You basically left behind 2 gallons of second running wort in your MLT. You could have simply added 4 gallons and drained 4 gallons since grain absorption is done at this point, and not left behind those sugars. This will account for some percentage efficiency drop - not a ton but some amount (maybe 2% maybe 7%) - the numbers would have to be worked out.

Determining your mash efficiency (accurate preboil gravity and volume) and then your brewhouse efficiency (accurate postboil gravity, kettle loss, and fermenter volume) should provide you some clues as to where you're missing out on some sugar. Your process seems reasonable enough so I suspect either the MLT second running losses and/or crush was the issue with this batch. Keep notes on precise volumes and gravities and you can determine where improvement can be made.

Edit: I batch sparge and was getting 84% brewhouse/fermenter efficiency with minimal losses. I've since brought that down to 80% through a (very) slightly coarser crush and less sparging to the betterment of the beers. Sometimes, "less is more"

 

[pretzelb]

A mash efficiency of 64% is actually on the high side for a batch sparge.

Not to toot my own horn, but my fly sparging method routinely achieves 80% mash to kettle.

I'm not sure about that. Batch and biab methods can usually get to the 70s and 80s. Seems like Kal gets 99% with his fly sparging.

To the OP, I think you have lots of advice so far. One thing to consider is just changing a single variable at a time. It can help while learning. To aid with that be sure you have a good thermometer.

For a bolder approach you can make some cheap changes. Try a cooler for the mash. Or try a biab method which (with a pulley) could allow you to heat your kettle during a mash if the temp drops.

 

[MrVix]

My suggestions:

Use 5.2 PH stabilizer
Use a higher water to grain ratio...(wetter is better)
Mash for 75 minutes
Stir the hell out of your sparge
Sparge for a full 15 minutes...stirring often

 

[pricelessbrewing]

My suggestions:

Use 5.2 PH stabilizer
Use a higher water to grain ratio...(wetter is better)
Mash for 75 minutes
Stir the hell out of your sparge
Sparge for a full 15 minutes...stirring often

NO to 5.2. It's a **** product, and should disappear from every homebrew store in the world.

 

[doug293cz]

My suggestions:

Use 5.2 PH stabilizer
Use a higher water to grain ratio...(wetter is better)
Mash for 75 minutes
Stir the hell out of your sparge
Sparge for a full 15 minutes...stirring often

As priceless says, forget the 5.2 stabilizer. Our resident water experts can (and have in other threads) explain why it is worse than worthless.

Also, no need to let a batch sparge sit prior to run-off. Just stir well for about 5 minutes, and then drain away as fast as your MLT will let you. The stirring is more effective than sitting for getting the sparge wort to a uniform concentration.

Brew on

 

[DogSlobber]

Doug, thanks for the detailed info! That's a really helpful overview of contributing factors and the viscosity graph makes total sense. I almost always mash at 1.25-1.5 qts/lb mainly due to the size of my cooler. I'm curious now to try closer to 2 and see what happens. The problem is either I won't have any volume left to mash out or I would have to give up precious final beer volume, a tragedy I'm not sure I'm ready for! What would the negative effects be of not performing a mash out step to halt conversion? Obviously I could still sparge with 170F water, but the first runnings would not achieve that temp for a while. In your opinion, would decreased conversion due to not raising the temp for mash out cancel the increase due to thinner mash? Any resources you know of that quantify that?

 

[pricelessbrewing]

Conversion efficiency is really hard to estimate. All you can really do is look at all yhe contributing factors and try to check them off. If extra time, or a raised temp helps then it's likely you have other factors are lowering your conversion rate. You could mill finer, or mash longer, but both would probably not gain you anything if you were already doing one of those.

As far as mashout locking the wort makeup, unless it takes you 15+ min to get to above 170 then I wouldn't worry about it.

 

[doug293cz]

Doug, thanks for the detailed info! That's a really helpful overview of contributing factors and the viscosity graph makes total sense. I almost always mash at 1.25-1.5 qts/lb mainly due to the size of my cooler. I'm curious now to try closer to 2 and see what happens. The problem is either I won't have any volume left to mash out or I would have to give up precious final beer volume, a tragedy I'm not sure I'm ready for! What would the negative effects be of not performing a mash out step to halt conversion? Obviously I could still sparge with 170F water, but the first runnings would not achieve that temp for a while. In your opinion, would decreased conversion due to not raising the temp for mash out cancel the increase due to thinner mash? Any resources you know of that quantify that?

Are you batch sparging or fly sparging? A mash out to stop enzymatic action is not needed with batch sparging, as you can run-off very quickly and start heating to a boil immediately. There isn't that much time for the alpha amylase to chop up the polysaccharides into fermentable sugars. For long duration fly sparging, you may want to kill the enzymatic action. You really shouldn't depend on the mash out to help complete your conversion. That should be accomplished by grinding finer and/or mashing longer. It is possible to calculate the SG the wort would have in the mash at 100% conversion based just on the water to grain ratio. See: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Measuring_conversion_efficiency. You can then determine your % conversion by comparing the SG of a sample of the wort from the mash with the max achievable. Monitoring conversion progression by sampling the SG will be better than any possible projection based on a model.

Brew on