Mash efficiency when mashing out

I've been working hard to get a better hold on my mash, lauter and brewhouse efficiency numbers, and came up against something this past weekend that raised a question for me.

I mashed this recipe for 75 minutes at 148 *F, and after vorlauf and running a few quarts into my boil kettle I took a refractometer reading that came to about 1.088. Since the range I use is 1.25 qt/lb, that was about 96%, so I was happy. But then I remembered I had prepped a 185 *F mash-out liquor addition, so I added it, stirred, and after another vorlauf came to 1.075ish, which is more like 82% mash efficiency.

At first blush, this seems to make sense, because more water should dilute the sugars, right? But then I wondered, shouldn't a mash-out liberate at least some sugars and thus do better than 82%?

As for the batch, my preboil gravity showed that I was on track for 72% brewhouse efficiency, and I wound up in fine shape for my OG, but this is my question: what effect should I expect from a mash-out?

-Rich

I have been under the impression that mash out stops the conversion process. I must have read it somewhere.

I think you must be measuring wrong with your refractometer or it is off. The recipe you linked has an OG of 1.066. And you mentioned that you finished at that OG as well. That means that your pre-boil would have to have been less than that, probably 1.060 or so. How could a lauter of 1.088 and a sparge of 1.075 give you a pre-boil of 1.060? Something doesn't connect.

jethro55 said:

I have been under the impression that mash out stops the conversion process. I must have read it somewhere.

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Cute.

It also is supposed to loosen up sugars that would otherwise stay in the grain bed through increasing heat like an early partial sparge, right? Thus the word liberate and not convert.

-Rich

tektonjp said:

I think you must be measuring wrong with your refractometer or it is off. The recipe you linked has an OG of 1.066. And you mentioned that you finished at that OG as well. That means that your pre-boil would have to have been less than that, probably 1.060 or so. How could a lauter of 1.088 and a sparge of 1.075 give you a pre-boil of 1.060? Something doesn't connect.

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1.075 wasn't sparge, it was lauter (first runnings + mash-out liquor). I only ran off a few quarts before remembering my mash-out. Chalk it up to excitement over my new refractometer.

My sparge (measured roughly in the middle, not mentioned above) was more like 1.035ish.

-Rich

Your 1.088 reading gave you your mash efficiency at 96% That should be the highest efficiency that you achieve.
If you had added your mash-out water, and stirred well enough before draining anything from the mash, then you should have gotten the same 96%, but you said "I only ran off a few quarts before remembering my mash-out."
In that case, you would have lost your "few quarts" at 96%, and then added your mash out water to what remained. This will undoubtedly have a lower gravity because you are adding water to the mash, and your efficiency will also be lower because you had run off some 96% efficient wort before diluting with the mash out water.

This makes sense to me. I hope it makes sense to you as well.

-a.

Echoloc8 said:

Cute.
-Rich

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Yeah, I thought so. Just a courtesy bump.

Echoloc8 said:

Cute.

It also is supposed to loosen up sugars that would otherwise stay in the grain bed through increasing heat like an early partial sparge, right? Thus the word liberate and not convert.

-Rich

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No, raising the temp (which is not necessarily a mashout) does not "loosen up" sugars. Kai proved that with his cold sparge experiment. If you get an efficiency increase by increasing the temp at the end of e mash, it's likely due to gelatinization and conversion of starches left in the grain. To do a true mashout, the purpose of which is to stop conversion, you need to hold temps of 170+ for at least 20 min.

Denny said:

No, raising the temp (which is not necessarily a mashout) does not "loosen up" sugars. Kai proved that with his cold sparge experiment. If you get an efficiency increase by increasing the temp at the end of e mash, it's likely due to gelatinization and conversion of starches left in the grain. To do a true mashout, the purpose of which is to stop conversion, you need to hold temps of 170+ for at least 20 min.

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Wow, this is totally new information to me. In ten years of homebrewing I've literally never heard that a mash-out takes more time than it takes to stir up a mash that's been raised to 170 F.

I had read about Kai's cold-sparge results, but not done any thinking about the implications.

I obviously have reading to do. Got any thread recommendations? Are proper mashouts even standard practice any more, then?

-Rich

Echoloc8 said:

Wow, this is totally new information to me. In ten years of homebrewing I've literally never heard that a mash-out takes more time than it takes to stir up a mash that's been raised to 170 F.

I had read about Kai's cold-sparge results, but not done any thinking about the implications.

I obviously have reading to do. Got any thread recommendations? Are proper mashouts even standard practice any more, then?

-Rich

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I think many of those who continous sparge still do mashouts- because it takes like 45 minutes or longer to sparge and that's part of the time that it takes to fully denature the enzymes and halt conversion.

It's true that this happens at 168 degrees + or so, but it isn't instantaneous and it need to be held for 20 minutes before you can be assured that the enzymes are indeed denatured.

So, even if you did a mashout and brought the grainbed to 170, if you sparged with cold water, the enzymes could keep working on the mash if the temperature dropped again under 165ish.

Okay, I've done some reading.

First, it doesn't look like a mashout is really necessary for batch-spargers like me. So this is largely academic, since I probably won't be doing them any more. Keeping my brew day shorter by 20 minutes is worth it to me.

Second, in between Kai's single experiment and a tastybrew thread I found, the cold-sparge question may not be as cut and dried as is thought. Regardless, my question was really one of dilution anyway: given first runnings of X without a mashout, wouldn't performing a mashout necessarily reduce the SG of those runnings? If not, why not?

There may well be something about the difference between lauter and sparge I'm just not understanding.

...Wait wait wait. I think I have it. Mash efficiency is calculated based on mash thickness. Since I go for 1.25 qt/lb, 100% conversion would be 1.096ish. A mashout addition would change the ratio, so I'd have to recalculate, say for 1.33 qt/lb (or whatever the volume of the addition makes it), and check that against Kai's table for mash efficiency. Is that right?

-Rich

Echoloc8 said:

Second, in between Kai's single experiment and a tastybrew thread I found, the cold-sparge question may not be as cut and dried as is thought. Regardless, my question was really one of dilution anyway: given first runnings of X without a mashout, wouldn't performing a mashout necessarily reduce the SG of those runnings? If not, why not?



-Rich

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Mash efficiency and brewhouse efficiency are calculations.

Sure, if you dilute your runnings, the SG will change as will the volume. That doesn't change the mash efficiency.

Doing a mashout, or not, won't impact the efficiency.

But adding water to anything will of course reduce the SG.

If you have a quart of sugar water, and add a quart of plain water, you will reduce the SG of that as well. But it doesn't change the amount of sugar in the solution.

I hope that makes sense!

Yooper said:

Sure, if you dilute your runnings, the SG will change as will the volume. That doesn't change the mash efficiency.[...]If you have a quart of sugar water, and add a quart of plain water, you will reduce the SG of that as well. But it doesn't change the amount of sugar in the solution.

I hope that makes sense!

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It does. I'm still reconfiguring my head around efficiency calcs after Kai's "Troubleshooting" article. Conv efficiency is how much sugar was converted from the starch you have, not how much sugar is in the wort versus how much potential in the grains -- that's brewhouse efficiency.

It's hard to remember sometimes that SG is a measure of both sugar and water, not just sugar. If SG changes, then it could be water or sugars or both.

{Well, actually it's density, but for purposes of brewing it's how much dissolved sugar has changed the density of water.}

It's the price of having indulged in unscientific brew-think for so long. Obvious things can take a while to actually make sense.

-Rich

Echoloc8 said:

...Wait wait wait. I think I have it. Mash efficiency is calculated based on mash thickness. Since I go for 1.25 qt/lb, 100% conversion would be 1.096ish. A mashout addition would change the ratio, so I'd have to recalculate, say for 1.33 qt/lb (or whatever the volume of the addition makes it), and check that against Kai's table for mash efficiency. Is that right?

-Rich

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That's absolutely right.

-a.

Echoloc8 said:

Okay, I've done some reading.

First, it doesn't look like a mashout is really necessary for batch-spargers like me. So this is largely academic, since I probably won't be doing them any more. Keeping my brew day shorter by 20 minutes is worth it to me.

-Rich

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Yes you would be correct, the mashout is important when you are going to do a continuous sparge. This is because it can take up to an hour to continuous sparge, and raising the temp during the mashout is a way to make sure the enzymes are shut down. Otherwise they would continue to do their work during the duration of the sparge and possibly create some off flavors. A batch sparge only takes ten minutes so there is less risk of this happening.

Echoloc8 said:

It's hard to remember sometimes that SG is a measure of both sugar and water, not just sugar. If SG changes, then it could be water or sugars or both.

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A long time ago, I thought I was pulling amazing efficiencies on a batch or two, when looking back at my notes, I realized I just underestimated my boiloff. Kai's writeup on the partition of efficiencies is great for homebrewers, so I now I check my pre-boil gravity more carefully.

On a side note, I think homebrewers are good falling for the fallacy that correlation is causation. If I were to play that game, I would wager than many batch spargers' observation that mashout improved their efficiency derives from vigorously stirring their mash prior to the first drain.

It's drained too fast to be alpha amylase activity. I assert that for the same reason that denaturing enzymes is not instantaneous at mash-out temps.

lockwom said:

On a side note, I think homebrewers are good falling for the fallacy that correlation is causation.

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In bodybuilding there's a term called "broscience" for this sort of thing: techniques that feel right, that may have worked for you or your buddy's brother's cousin, but may well have correlation/causation issues. Stuff that's whispered like state secrets between people who may have brewed for decades with little knowledge of the whys or hows other than repetition.

Home brewing has a distressing amount of this.

-Rich

Echoloc8 said:

It does. I'm still reconfiguring my head around efficiency calcs after Kai's "Troubleshooting" article. Conv efficiency is how much sugar was converted from the starch you have, not how much sugar is in the wort versus how much potential in the grains -- that's brewhouse efficiency.

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Brewhouse efficiency also takes into account losses to trub etc.

I like to think of efficiency simply as a point total. It takes some reasoning out of it.

Start here:
http://www.beersmith.com/Grains/Grains/GrainList.htm

Take the potential sugar, multiply by pounds. That's your point total. How many gallons it's spread over isn't important.

Collect your wort - multiply gravity by gallons - then check it against the total points from your grain load. That's mash efficiency.

Rack your final product into the fermenter - take gravity and multiply by gallons - that's Brewhouse efficiency.

lockwom said:

so I now I check my pre-boil gravity more carefully.

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And volumes... every time you take a gravity reading, it needs to be accompanied with a volume, or it doesn't really tell you anything.

acidrain said:

And volumes... every time you take a gravity reading, it needs to be accompanied with a volume, or it doesn't really tell you anything.

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This. Quoted for truth.

-Rich

Echoloc8 said:

It's hard to remember sometimes that SG is a measure of both sugar and water, not just sugar. If SG changes, then it could be water or sugars or both.

{Well, actually it's density, but for purposes of brewing it's how much dissolved sugar has changed the density of water.}

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Right. The measure of sugar dissolved in water is Brix.

beaston said:

Yes you would be correct, the mashout is important when you are going to do a continuous sparge. This is because it can take up to an hour to continuous sparge, and raising the temp during the mashout is a way to make sure the enzymes are shut down. Otherwise they would continue to do their work during the duration of the sparge and possibly create some off flavors. A batch sparge only takes ten minutes so there is less risk of this happening.

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Hmm. Why the hell am I doing a fly sparge then, as a noob? It sounds BOTH easier and faster to batch sparge. The only reason I'm fly sparging is because that's how the Northern Brewer All Grain intro video says to do it. Do they have a reason to recommend that approach over batch sparging?

I have also been fly sparging and I too have been wondering why the hell I am adding an extra 45 minutes to my brew day. I got the technique from The Brewmaster's Bible, where I learned all my brewing techniques before finding this website. It seems like a lot of home brewing knowledge until recently was just based on copying what the big breweries do, without considering that brewing on a smaller scale means alternative ways to achieve the same result.

Trippel-A said:

Hmm. Why the hell am I doing a fly sparge then, as a noob? It sounds BOTH easier and faster to batch sparge. The only reason I'm fly sparging is because that's how the Northern Brewer All Grain intro video says to do it. Do they have a reason to recommend that approach over batch sparging?

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I don't think they have a reason to recommend it, except that is how the guys that made the video do it and are comfortable.

Batch sparging has only been really mainstream for about 8-10 years or so, maybe less, so if you learned to brew a long time ago that was they only way you knew how to do it.

Great discussion. I'm a slow batch sparger. I tend to mash out and recirc for 20 minutes to get a true denaturing of the enzymes. I have often thought of fly sparging since I have 2 pumps, but batch sparging just seems to keep working for me, and my efficiency is predictable. It's always better if I sparge with multiple batches too. I'm sure there's a scientific reason for that, but I don't know what it is.

jbaysurfer said:

Great discussion. I'm a slow batch sparger. I tend to mash out and recirc for 20 minutes to get a true denaturing of the enzymes. I have often thought of fly sparging since I have 2 pumps, but batch sparging just seems to keep working for me, and my efficiency is predictable. It's always better if I sparge with multiple batches too. I'm sure there's a scientific reason for that, but I don't know what it is.

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If you have to use multiple batch sparges, you might want to assess your process and get to the root of the problem. Really, the only reason to do more than one is if your mash tun is too small to hold all the water for a single sparge. In that case, you might want to investigate using a larger mash tun. I do a single batch sparge and get 83% efficiency and great beer, so it can be done.

Denny said:

If you have to use multiple batch sparges, you might want to assess your process and get to the root of the problem. Really, the only reason to do more than one is if your mash tun is too small to hold all the water for a single sparge. In that case, you might want to investigate using a larger mash tun. I do a single batch sparge and get 83% efficiency and great beer, so it can be done.

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I appreciate the feedback Denny, but I have only done multiple batches because it seems to help my efficiency. No other reason. Is there a reason NOT to do multiple batches? In general I do two batches and just split the sparge evenly between them. But to be honest, I have also just started getting into water chemistry and it could be the case that my multi-batch increased efficiency experience happens to be correlation vs. causation. Your thoughts?

jbaysurfer said:

I appreciate the feedback Denny, but I have only done multiple batches because it seems to help my efficiency. No other reason. Is there a reason NOT to do multiple batches? In general I do two batches and just split the sparge evenly between them. But to be honest, I have also just started getting into water chemistry and it could be the case that my multi-batch increased efficiency experience happens to be correlation vs. causation. Your thoughts?

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There are a couple reasons not to do multiple sparges...one is that you're wasting time and energy and not getting to the root of your problem. If you identify and correct that issue, you're ahead for every batch you make from then on. The other reason is that every time you do another sparge, you reduce the buffering power of the grain and run a (slightly) increased risk of tannin extraction. As I said, 99% of the time, it's the crush. If I can get an average 83% efficiency, anyone can.

How much of an increase do you get from 2 sparges? For me, the increase is so small it isn't worth my time and effort. Also, have you ever checked your conversion efficiency? Maybe that's where the problem is.

I do two sparges. I mash on the thin side (1.75 qts/lb) and after a mash out, I vorlauf, and drain (pump). I then add half my sparge water (pH adjusted) and repeat. For my last sparge, I gravity drain once I'm done with the vorlauf. After the first batch sparge, the kettle goes on the burner, and the final sparge drains into a bucket and gets added to the usually just starting to boil wort. Another 5-10 min. and I'm at full boil

If I didn't have a pump, I probably would not do it this way.

I crush the bejeezus out of my grain (after conditioning)

I average 92% efficiency. O'fest yesterday had 8 lbs of grain total to give me 4.8 gal. of 1.056 wort