Mash-out and wort fermentability

Does a direct-heat mash-out (taking about 10-15 min. on a 10-gallon batch to go from 150-something°F to 168°F) result in a slightly less fermentable wort (although with slightly higher efficiency) compared to a batch sparged no mash-out or a hot water infusion or decoction mash-out that doesn't spend that extra time in the alpha-amylase temperature range?

Over a year old and no answer? I found this at the bottom of another page. I was thinking the same thing. Any answer from anyone smarter than me?

efficiency wont be affected as conversion should be complete by that point. attenuation may be, but thats cuz you're denaturing enzymes with a mash out where as the other way you're still letting the amylase chop up sugars

Fermentability and attenuation are set by the main mash. The mash out step does not affect that. Although, the mash out does denature the remaining enzymes and stop any further starch and sugar conversion.

But, the mash out does have a significant effect on the efficiency of the mash. You will get several points more extract from the mash when performing a mash out.

Although, the mash out does denature the remaining enzymes and stop any further starch and sugar conversion.

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Raising the wort to 168-170 does not denature the alpha-amylase. It will keep working. The beta will be denatured, so the alpha will be breaking up longer dextrins into medium dextrins, which may be fermentable.

As to the original question, raising the temperature above 162 will denature the beta amylase, which will significantly decrease the formation of maltose, and lead to a less fermentable wort. However, if you spend enough time before raising the temp., the effect will probably be minimal.

mabrungard said:

But, the mash out does have a significant effect on the efficiency of the mash. You will get several points more extract from the mash when performing a mash out.

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As temperature is unrelated to efficiency, can you please explain how a mash out could raise your efficiency.

There's two ways a mash out might increase efficiency. First, if you really were not fully converted, the early stages of a mashout ramp up will peak beta amylase and increase alpha activity also. Of course, it's relatively short lived but if you were at 95% conversion before the mashout, you may end up with 98% by the end. Second, the slight increase in sugar solubility at higher temps may increase lauter efficiency. Kaiser messed with cold sparging a bit and may have at least partially busted the latter claim so it's less influential if at all.

I thought maybe the higher temp might liberate some starch that otherwise would not have been and since the alpha is not fully denatured (as pkeeler mentioned) those newly liberated starches would get converted.

I think it may depend what temp your mash was before the mashout...big difference between 148* F and 158* F.

I don't think an extra 10 min heating from 150*-something to 168* would make much difference in fermentability but I'm just shootin' from the hip. I usually either mash-out via direct-heat, infusion, or thin-mash decoction (almost always one of the three) and don't notice a difference.

dcp27 said:

As temperature is unrelated to efficiency, can you please explain how a mash out could raise your efficiency.

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Ah, temperature is directly related to starch and sugar extraction from the grain, thus the improvement in extract that is evident when performing decoction mashing. Additionally, I have performed over a hundred RIMS mashes and have observed 'many' points of increased gravity with my refractometer with before and after mash out samples (I say 'many' since I don't have my brewing logs in front of me).

Anyone that does not perform a mash out step is leaving some efficiency behind.

mabrungard said:

Anyone that does not perform a mash out step is leaving some efficiency behind.

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sure mashing out increases your efficiency out of your first runnings, but does your overall efficiency change with and without a mash-out? even if it did increase it by a few meager points, they're highly unfermentable and thus mostly useless added points. aside from causing the alpha amylase going into hyper mode and converting whatever starches are left, the mash out doesnt add any sugars that your sparge wouldnt.

dcp27 said:

sure mashing out increases your efficiency out of your first runnings, but does your overall efficiency change with and without a mash-out? even if it did increase it by a few meager points, they're highly unfermentable and thus mostly useless added points. aside from causing the alpha amylase going into hyper mode and converting whatever starches are left, the mash out doesnt add any sugars that your sparge wouldnt.

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Why would a mashout extract highly unfermentable and thus mostly useless added points? That makes no sense whatsoever. The higher temps increase the solubility of the sugars allowing them to be more completely extracted from the grain bed. IME, a mashout increases the yield by much more than a few meager points. You are right that a mash out does not add any sugars, but it does enable more efficient extraction of the already converted sugars which will result in higher sparge efficiency.

Catt22 said:

Why would a mashout extract highly unfermentable and thus mostly useless added points? That makes no sense whatsoever. The higher temps increase the solubility of the sugars allowing them to be more completely extracted from the grain bed. IME, a mashout increases the yield by much more than a few meager points. You are right that a mash out does not add any sugars, but it does enable more efficient extraction of the already converted sugars which will result in higher sparge efficiency.

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If the mashout were to add to your efficiency, it would be because it converted some leftover starches. since the temps this would be converted at would be so high, the sugars would be longer and will be largely unfermentable.

I agree that the higher temps should increase the solubility of the sugars (although like Bobby_M pointed out, Kaiser may have partially busted that), but what is the mash-out then extracting that the sparge would not?

dcp27 said:

If the mashout were to add to your efficiency, it would be because it converted some leftover starches. since the temps this would be converted at would be so high, the sugars would be longer and will be largely unfermentable.

I agree that the higher temps should increase the solubility of the sugars (although like Bobby_M pointed out, Kaiser may have partially busted that), but what is the mash-out then extracting that the sparge would not?

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I've checked my mash conversion efficiency more than a few times using Kaiser's method and it was always at or very near 100%. The results were so consistent that I no longer bother with the test. IMO, unless you are screwing up the mash somehow, there will be no significant amount of starch left to convert and thusly, very little to no unfermentable sugars will be extracted. I don't have any problems with my beers not finishing out, so I see no reason to avoid doing a mash out. My extraction efficiency, however, has significantly improved since I began routinely doing a mash out, so I plan to continue doing one.

Catt22 said:

I've checked my mash conversion efficiency more than a few times using Kaiser's method and it was always at or very near 100%. The results were so consistent that I no longer bother with the test. IMO, unless you are screwing up the mash somehow, there will be no significant amount of starch left to convert and thusly, very little to no unfermentable sugars will be extracted.

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totally missing my point. I never advocated that there was sugar added from the mash out, only that if mash out were to increase efficiency it would be due to converting any remaining starches that weren't. I agree there is essentially no added sugar from the mash out. if there is, its in the realm of < 3%.

My extraction efficiency, however, has significantly improved since I began routinely doing a mash out, so I plan to continue doing one.

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just to be clear, is this beyond your first runnings?

dcp27 said:

If the mashout were to add to your efficiency, it would be because it converted some leftover starches. since the temps this would be converted at would be so high, the sugars would be longer and will be largely unfermentable.

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Can you explain why unfermentable sugars are such a bad thing? Don't we want some of that?

SpanishCastleAle said:

Can you explain why unfermentable sugars are such a bad thing? Don't we want some of that?

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Of course we do, I'm not saying we don't or that they're bad at all. My point is that the only way a mash out could actually add to your efficiency would be if it converted the very minimal, <3 %, amount of starches left. However, because these sugars would be so unfermentable it would decrease the fermentability. so if you want to count that little bit higher as an increase in efficiency despite it decreasing fermentability, all the power to you. IMO, its insignificant

OK gotcha. TBH, I'm not worried about getting high efficiency and intentionally try to keep it ~75% (mostly by sparging less). The tiny extra expense from a bit more malt is a non-issue for me. Fermentability is a big issue imo but I always seem to get better attenuation with a given yeast strain and mashing at a given temp than most recipes suggest, so a little less fermentability is often welcome for me (yes, I calibrate my thermometers ).