What Does a Mash Out Do?

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GrowleyMonster

GrowleyMonster

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Just curious what the purpose of mashing out at say 170 might be. Seems like destroying enxymes is counterproductive.
 
If you use traditional mash tun, traditional lauter can take an hour. That will continue to make the wort more fermentable than you might want, so hitting 170 at the end of 60-90min mash stops it from making a more fermentable wort.
 
balrog said:
If you use traditional mash tun, traditional lauter can take an hour. That will continue to make the wort more fermentable than you might want, so hitting 170 at the end of 60-90min mash stops it from making a more fermentable wort.
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That makes no sense to me.

Once the enzymes have converted all they can (usually after about 60 mins) then no matter how long you leave them they aren't going to make the wort more fermentable.

Or am I wrong?

I thought the idea of mashing out was to raise the temperature to allow the sugar to better dissolve into the solution, or something along them lines.
 
Gilbert Spinning Horse said:
That makes no sense to me.

Once the enzymes have converted all they can (usually after about 60 mins) then no matter how long you leave them they aren't going to make the wort more fermentable.

Or am I wrong?

I thought the idea of mashing out was to raise the temperature to allow the sugar to better dissolve into the solution, or something along them lines.
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Googled-
The primary purpose of a the mashout step is twofold– in addition to halting enzymatic activity and locking in the intended wort profile, raising the temperature at the end of the mash also reduces viscosity to make for easier lautering.
 
Imagine mashing as an exercise in pruning an overgrown bush. One major enzyme are your pruning shears, slicing the ends off the small twigs. The other major enzyme are your saw, able to cut right through the middle of thumb sized branches.

The first step is to thin out a few of the larger branches with your saw and then clean up the shape of the bush with the shears. The bush now looks great. 100% conversion.

Now look at the big pile of debris at your feet and the bin it's supposed to go in. You've got two choices...

A - Call your tools done for the day, then try to stuff all that not-broken-down debris into its bin. Putting the tools away is the mash out.

B - No mash out. Keep weilding those tools on the debris pile. Break those big complicated branches into smaller and smaller pieces. Getting that small stuff into the bin is going to be thoroughly easier.

Now, the difference in viscosity between 150° and 170°? Yeah, I don't know about that.
 
The purpose is to stop the conversion process. I know people are saying this, but hang with me for a minute. Imagine you want a beer with some mouthfeel, not a thin watery beer. As more sugars convert, the thinner the beer will be. Say you mash for 90 minutes, and that gets the beer where you want it for og. Now, the mashout will take another while, up to an hour. As you mash out at mashing temp, say 152, the sugars will continue converting and the beer will keep getting thinner. Instead of a rich full beer like you want, now you have a thin watery beer. Instead, at the end of the 90 minutes, you raise the temp to kill the conversion enzymes, and all conversion stops. Now you have it at just the right "thickness". It's kind of like adding water to flour. Do you keep adding water while you're stirring, or do you get it right where you want it and stop adding water?
 
if your grain is milled coarse, not all the starches will be converted in 60 minutes, maybe not even in 90 minutes. Mash out speeds up the alpha enzyme until it finally destroys it which takes some time even at 170F and since beta enzyme is first to be destroyed, the alpha adds more dextrines for a fuller tasting beer. There is no appreciable difference in the viscosity.
 
If you start your boil soon after completing the mash, then maybe not so important. But if you do really big batches and there might be a longer time period before you start the boil, then it's probably more important to get to mash out temps.
 
If I'm understanding this right, mashing out will lock in the OG, otherwise it will keep going up due to enzymatic activity?
 
dan46nbrew said:
If I'm understanding this right, mashing out will lock in the OG, otherwise it will keep going up due to enzymatic activity?
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No. It will lock in the wort composition, meaning the ratio between the different sugars in the wort. Otherwise it will continuously shift toward shorter sugars, meaning more fermentability.
 
Gilbert Spinning Horse said:
(usually after about 60 mins)
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It would be a fine experiment to take 1/2 the wort from the mash and set it aside. See if the OGs are the same, and more importantly, boil and ferment them the same and see if the FGs are the same. There are numerous posts on here about those who set the mash up one afternoon/evening and don't start the boil until the next morning, so they don't have to do it all in the same day. And while it does not produce MORE sugar with a longer mash, it produces different ratio of short to long chain sugars, which different yeasts convert at different efficiencies. Typically a longer mash will yield a LOWER FG. The OG doesn't really change unless as @RM-MN points out that due to grit size (crush) you haven't really converted all starch to sugar.
 
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Starch chains are made up of thousands of glucose molecules bonded together. Beta amylase only chops off two glucose (maltose) chunks from one end of a starch chain, so everything created by beta amylase is fermentable. Alpha amylase, on the other hand chops the starch chain in random locations, producing random length shorter chains, but only the one unit (glucose), two unit (maltose), and (with some yeasts) three unit (maltotriose) sugars are fermentable, The longer chains that result from alpha amylase action are not fermentable, even though they are soluble and contribute to the SG.

Let's look at a simplified example of alpha amylase action. Say we start with a bunch of starch chains all 1000 glucose units long. If an alpha amylase acts on it, cutting it into two pieces, the pieces could vary anywhere from a 1 and a 999 unit chain to two 500 unit chains. The average length of chains after the first round of action is 500 units. After a second round of action, the average length of chains is 250 units, after the third round 125 units, and continuing until everything is 1 or 2 units long (ignoring the effect of branches in amylopectin.) After each round of action there are more of the fermentable 1, 2 & 3 unit molecules and fewer of the longer, unfermentable molecules. The longer alpha amylase acts, the more fermentable the wort becomes, and the less unfermentable carbohydrate remains in the wort.

The previous example is not completely realistic because the original starch chains have a range of lengths (as measured by number of glucose units), the alpha amylase doesn't act sequentially, but rather continuously, and there may be a preference for creating longer chains than shorter chains.

A mashout stops the continuing action of alpha amylase, so the fermentability of the wort stops changing, i.e. locks-in the molecular weight distribution of the carbohydrates and the fermentability of the wort. Beta amylase is pretty much all denatured by the end of the mash, except in cases of lower limit mash temps.

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SG and fermentability do not track each other during a mash, since both non-fermentable and fermentable carbohydrates (and proteins, lipids, etc.) contribute to the SG. Thus the SG is a measure of how much material has dissolved into the wort, regardless of how fermentable it is. The first step in the mashing process is the gelatinization of the starch on the surface of the grain grits. Once some of the starch is gelatinized, the amylase can start chopping up the starch chains. Any sugars, dextrins (glucose chains longer than sugars, and shorter than starches), and shorter, and therefore soluble starch chains will go into solution. Once a carbohydrate molecule goes into solution, it raises the SG of the solution, and the SG does not increase appreciably as that carbohydrate molecule gets chopped into smaller and smaller pieces. Thus a mash will reach maximum SG before it reaches maximum fermentability.

When measured by SG, conversion is complete once all of the available starch has been gelatinized and rendered soluble by the action of the amylase enzymes. When measured by an iodine test, conversion is complete once all of the available starch has been gelatinized and rendered into chains short enough that they won't trigger the iodine/starch reaction. In neither case has the wort reached maximum fermentability (or conversion of all starch to the minimum possible chain lengths.) In practice the time difference between complete by SG vs. complete by iodine test is short, since it doesn't take long to reduce soluble starch chains to dextrins that will "pass" the iodine test. You can get a false iodine test if you don't include grain in the iodine test, as the grain can still contain convertible starch when a wort only sample passes the test.

A mashout will accelerate the gelatinization of any ungelatinized starch remaining at the end of the allotted mash time. This will result in more carbohydrates going into solution, and thus raising the SG of the wort. This is what goes on when brewers observe an increase in conversion and mash efficiency when they do a mashout vs. when they do not mash out. A mashout will not increase the conversion or mash efficiency of a mash that has already gelatinized 100% of the available starch.

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The viscosity reduction due to a mash out is minimal. If you massage the data found here, you can estimate that the viscosity reduction going from 150°F to 170°F is about 16%. You get a much larger viscosity reduction once you start sparging, or in the case of no sparge, you start at a much lower viscosity.

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A mashout does not cause any more sugar to go into solution in the wort. The solubility limit of maltose at 150°F (65.6°C) is 66.6% or 66.6°Plato. The max °Plato achievable in a mash is about 27°P, when using a mash thickness of 1 qt/lb. Thinner mashes have lower max °P. Since all sugar is in solution when created in the mash, and the concentration is well below the solubility limit, no sugar will precipitate out of solution in the mash. Thus there is no sugar to dissolve by increasing the solubility (by raising the temp.)

Brew on :mug:
 
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Wow, so many extremely informative, knowledgeable, and scholarly answers! Thanks again, brewers, for increasing my knowledge! I think my takeaway on this is I still don't need to do a mash-out for what I am brewing, and I can just keep going straight from mash, sparge, and bag sqeeze, right into the boil. But now I see why some guys do it or why some recipes might call for it.
 
lumpher said:
The purpose is to stop the conversion process. I know people are saying this, but hang with me for a minute. Imagine you want a beer with some mouthfeel, not a thin watery beer. As more sugars convert, the thinner the beer will be. Say you mash for 90 minutes, and that gets the beer where you want it for og. Now, the mashout will take another while, up to an hour. As you mash out at mashing temp, say 152, the sugars will continue converting and the beer will keep getting thinner. Instead of a rich full beer like you want, now you have a thin watery beer. Instead, at the end of the 90 minutes, you raise the temp to kill the conversion enzymes, and all conversion stops. Now you have it at just the right "thickness". It's kind of like adding water to flour. Do you keep adding water while you're stirring, or do you get it right where you want it and stop adding water?
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im going to say mashout isnt exactly necessary. a lot of home brewers dont. I run it to the boil kettle. Once i get an inch of wort to the bk, the heat goes on. once the bk hits 170 (generally my mash tun is at 152-154 so 170 isnt that far to raise the temp another 16-18 degrees) it'll stop the enzyme activity. Ive yet to have a watery beer.
 
https://www.sciencedirect.com/topics/food-science/dextrinization
"Dextrinisation
Dextrinisation, also known as pyroconversion, refers to two aspects of the structural modification of starch. The first is a partial depolymerisation achieved through hydrolysis. Hydrolysis is the reverse of condensation. It is the addition of water across a bond resulting in cleavage of that bond. It is usually brought about by dry roasting the starch either alone, making use of its natural 10–20% moisture content, or in the presence of catalytic quantities of acid. This gives rise to a range of polymer fractions of varying chain length (low conversion). The second aspect involves a recombination of these fragments (repolymerisation) but this time in a branched manner (high conversion). The starches so produced are called dextrins or pyrodextrins. They are typically classified as white dextrins, yellow dextrins or British gums depending on their range of viscosity, cold-water solubility, colour, reducing sugar content and stability."
 
Terpene said:
https://www.sciencedirect.com/topics/food-science/dextrinization
"Dextrinisation
Dextrinisation, also known as pyroconversion, refers to two aspects of the structural modification of starch. The first is a partial depolymerisation achieved through hydrolysis. Hydrolysis is the reverse of condensation. It is the addition of water across a bond resulting in cleavage of that bond. It is usually brought about by dry roasting the starch either alone, making use of its natural 10–20% moisture content, or in the presence of catalytic quantities of acid. This gives rise to a range of polymer fractions of varying chain length (low conversion). The second aspect involves a recombination of these fragments (repolymerisation) but this time in a branched manner (high conversion). The starches so produced are called dextrins or pyrodextrins. They are typically classified as white dextrins, yellow dextrins or British gums depending on their range of viscosity, cold-water solubility, colour, reducing sugar content and stability."
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The question I have is: in a typical mash is the pH low enough, and the temp at mashout high enough, to cause significant amounts of condensation to occur? Or, could an increase in dextrins formed during a mashout actually be caused by gelatinization of the starch remaining after the lower mash rests, and insufficient amylase enzymes and time to reduce the larger dextrins to limit dextrins (i.e. incomplete hydrolysis of starch freshly solublized during the mashout)?

Brew on :mug:
 
doug293cz said:
The question I have is: in a typical mash is the pH low enough, and the temp at mashout high enough, to cause significant amounts of condensation to occur? Or, could an increase in dextrins formed during a mashout actually be caused by gelatinization of the starch remaining after the lower mash rests, and insufficient amylase enzymes and time to reduce the larger dextrins to limit dextrins (i.e. incomplete hydrolysis of starch freshly solublized during the mashout)?
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Good questions. I don't know the answers -- just have more questions.

If condensation reactions do occur in mashout conditions, wouldn't they also continue to occur during the boil?

Also, how do we know that raising temp at mashout increases dextrins at all, by any mechanism? If there's good info/research on this I would be interested to see it.
 
I've done a few overnight BIAB mashes and I get greater efficiency and also more fermentability that results in a lower FG.
This is great if you are making a super dry brut IPA or a low calorie session ale or light lager, or want to squeeze all the alcohol you can out of your grain, but not so great for other styles.
So stopping the conversion does make sense if you are doing a lengthy sparge process.
I've ditched my mash tun and fly sparging and now almost exclusively do BIAB and just crank up the heat when I do pull the bag so the mash out happens on the way to getting the boil going.
 
Terpene said:
Good questions. I don't know the answers -- just have more questions.

If condensation reactions do occur in mashout conditions, wouldn't they also continue to occur during the boil?

Would probably depend on whether or not the condensation reactions are enzyme mitigated, and the denaturing temp of any enzymes involved.

Also, how do we know that raising temp at mashout increases dextrins at all, by any mechanism? If there's good info/research on this I would be interested to see it.

I don't know that any increase in dextrins occurs during the mash out, but there are those on HBT (and probably elsewhere) that claim that it does. Perhaps one of them would weigh in with references.
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Brew on :mug:
 
madscientist451 said:
I've done a few overnight BIAB mashes and I get greater efficiency and also more fermentability that results in a lower FG.
This is great if you are making a super dry brut IPA or a low calorie session ale or light lager, or want to squeeze all the alcohol you can out of your grain, but not so great for other styles.
So stopping the conversion does make sense if you are doing a lengthy sparge process.
I've ditched my mash tun and fly sparging and now almost exclusively do BIAB and just crank up the heat when I do pull the bag so the mash out happens on the way to getting the boil going.
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the whole BIAB thing has me curious and you do an overnight mash? how do you keep the tannins from becoming too high?
 
On pages 220 -229 in Technology Brewing and malting by Kunze,are the times and temps for mashing and it states that a mash out temp of 172* causes the B glucans that weren't converted during MALTING are brought into the mash and degraded by what is left of the a amylase,giving better head retention. Buy the book,it's where I get most of questions answered.
 
I put first 2 pints of wort into my boiler and blast it with 3 kW. As soon as it reaches 90 deg C I add another 4 pints, and so on. Works for me.
 
lumpher said:
The purpose is to stop the conversion process. I know people are saying this, but hang with me for a minute. Imagine you want a beer with some mouthfeel, not a thin watery beer. As more sugars convert, the thinner the beer will be. Say you mash for 90 minutes, and that gets the beer where you want it for og. Now, the mashout will take another while, up to an hour. As you mash out at mashing temp, say 152, the sugars will continue converting and the beer will keep getting thinner. Instead of a rich full beer like you want, now you have a thin watery beer. Instead, at the end of the 90 minutes, you raise the temp to kill the conversion enzymes, and all conversion stops. Now you have it at just the right "thickness". It's kind of like adding water to flour. Do you keep adding water while you're stirring, or do you get it right where you want it and stop adding water?
Click to expand...
I have heard a lot of people try to explain the reasoning behind Mash out, some ridiculous. But, your explanation is the best one I have heard. Thanks
 
Nope, it's not necessary. I rarely do a mashout. Normally I go straight from mash to boil, also. While I'm sparging, the wort is heating up in the boil kettle. When I'm done sparging, that goes straight into the boil also. Cuts my time way down, and the resultant beer tastes good either way. If I'm trying to do a beer for a competition, then I'll mash out "properly"; otherwise, mash to boil works for me.
 
lumpher said:
Nope, it's not necessary. I rarely do a mashout. Normally I go straight from mash to boil, also. While I'm sparging, the wort is heating up in the boil kettle. When I'm done sparging, that goes straight into the boil also. Cuts my time way down, and the resultant beer tastes good either way. If I'm trying to do a beer for a competition, then I'll mash out "properly"; otherwise, mash to boil works for me.
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Going straight from mast to boil is the key thing here for why it's not necessary.

If it's going to be a while before boil, then a mash out should be done. Homebrewers typically go straight into a boil. Others brewing larger volumes may not be able to bring it to boil before enzymes and other things change the character of the wort.
 
I like Doug's post because it highlights the difference between gravity and fermentability. Homebrewers are often obsessed with gravity and not so much with fermentability. But fermentability is where the artistry happens with mashing. The great German and Belgian examples are all very well attenuated. I do not like to use the term "dry" here but they pretty much all do not have much extra residual sugar lying around.

With regards to if the mashout is necessary, that is a decision that you need to make as to what type of brewing you are going to do.
 

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