Fermentability limit and mash duration

[Mer-man]

I brewed: 95% WEY Barke Pils, 5% WEY CaraHell; mashed in approx 63C and let my system raise the temp to about 65-66C over time.

Last time I brewed this, I mashed for 60 minutes and my FFT came in at 1.010.
This time I brewed it, I (had to deal with a baby so I had to walk away and) mashed for 2 hours and 15 minutes and my FFT came in at 1.007. OGs were approximately the same.

Has anyone (not from Brulosophy) done any datalogging where mash duration is the variable?

We have all heard vague statements on "mash longer for greater fermentability" that I always presumed were related to getting complete conversion, but the OGs were on par.

 

[Miraculix]

There is some info available in German on that topic, books have been apparently written, but I don't know the titles or if they are available in English.

You have to keep in mind that high fermentability mainly is caused by beta Amylase activity. Unfortunately beta is quite unstable and denatures at its working temperature with a half life of about 20 to 30 minutes (at 61c ). The higher you go, the quicker it denatures, even a few degrees hotter and it will only remain intact for a few minutes.

The second problem is, starch is a huge molecule and beta can only attack at its ends this means it takes a lot of time for beta alone to chop the starch into pieces.

Alpha Amylase can cut the starch into bigger pieces in the middle of the molecule, creating unfermentables but also more end points for the beta to work on. Problem is, alpha works best at 72c, beta craps out there in minutes.

So what you want is to either mash very long and very low, around 60c for two hours, or at 65 for a mixed alpha and beta activity for around an hour. You can also first rest at 60 for half an hour to get the best out of the beta and then raise to 65 for combined action.

The key is, if mashing low, you also need to mash long as the beta needs more time without that much of alpha activity to support it.

 

[dmtaylor]

Early in my all-grain brewing, I mashed a dozen or more batches to determine the minimum time required for good efficiency and attenuation. I have not experimented with the long mashes, just short ones. What I found is that attenuation is indeed the main variable -- efficiency doesn't change much at all -- and that when mashing for 30 minutes, I could reach my desired attenuation about 50% of the time, but when mashing for 40 minutes, I could get close enough every time, relative to a "standard" 60-minute mash. In recent years now I mash almost every batch for 45 minutes (adding just a small 5-minute cushion of insurance to the 40-figure). I've been making great beer this way for 10 years now. I leave it to others to experiment more with long 2+ hour mashes to determine that effect. In my view, there is a diminishing returns thing with longer mashes but this might be appropriate for beers where you want to maximize attenuation. For most beer styles though... 40 minutes is "good enough" and a taster is less likely to notice a big difference vs. a longer mash.

P.S. I crush the grains hard. There is a lot of flour in my milled grain, and always has been that way. To anyone who doesn't crush hard, they'll likely need to remedy that before running any serious experiments. Poor crush definitely affects efficiency. Crush hard, then efficiency is not variable anymore.

 

[ESBrewer]

Those are not on par..they are 3 thousandths apart which makes a difference. Using the same yeast and mash times, I never see a variation that high, even if the mash temp tends to vary by 0.5° - 1 °C depending on batch. Both are already pretty low for a beer as it is impossible to make a beer that would be 100% fermentable, there is always certain amount of compounds extracted that will affect the gravity and that are unfermentable so that no temperature or time will help. So depending on several factors, 1.007 may be already close to what is possible to obtain in this beer. There are limits and those depend on OG, grain bill & yeast strain, too. And the mashing efficiency/fermentability depends on more things than time & temp. pH, grain crush, ions...

 

[dmtaylor]

*deleted* (but was thinking ESBrewer might be confusing OG vs. FG...)

 

[ESBrewer]

Yes, I mean that FG 1.007 and 1.010 are definitely not the same thing, there is a measurable difference that seems to be caused by mashing long. If 1 hr already gives you FG 1.010, there is not so much room for improvement in attenuation, depending on the amount of absolutely unfermentable compounds such as melanoidins, proteins etc. If you would have a beer with FG 1.022 (1hr) the longer mash would potentially give you more than 0.003 points extra. Depending, of course, on many things. I think some interesting case studies are about to be performed in a (Danstar) London ESB thread where beers of some brewers are stalling at 1.020+.

 

[eric19312]

Braukaiser produced some data which would support your thinking that the longer mash lead to a more fermentable wort and also added data from Narziss to his discussion.
http://braukaiser.com/wiki/index.ph...ity_and_efficiency_in_single_infusion_mashing

 

[mabrungard]

I recall it was the brewers from Two Brothers Brewing giving a speech at one of the homebrew conferences that stated that STARCH extraction and conversion is completed in about 15 minutes of mashing. (ie: the iodine test is negative) However, that freshly converted starch is in the form of long-chain dextrins and sugars. Additional mashing time enables enzymes the opportunity to cleave those long chains into shorter and more fermentable sugars.

Reportedly, Two Brothers 'ends' their mash at 15 minutes, but the additional time necessary to vorlauf, lauter, and sparge the mash probably provides the necessary time for those other enzymatic processes to occur to an acceptable degree. Remember, they are dealing with large volumes and it takes more time than we homebrewers can accomplish with our little systems.

 

[Mer-man]

@ESBrewer: OG, not FG. The whole point here is difference in FG. But what you really mean is no, you don't have anything to add.
Since you brought the stalling thread up, do you have a link?

 

[ESBrewer]

Yes sorry for my misconception, I was initially reading that FGs were on par (probably because the whole point of the story was the FG..). OGs are pretty much expected to be the same as starch is solubilized very soon (as mabrungard noted). Even 1 hr is excessive for that purpose. But as you showed, fermentability tends to rise during the second hour of mashing. And especially so if there is a good amount of dextrin around and the mash temperature is low enough so that the enzymatic activity is preserved. It was interesting to see your results regarding the longer mash time, because most of the time homebrewers stick to 1hr mash even if there are some problems with attenuation. It appears that mashing low is useful for fermentability, but for this purpose you typically need to mash longer than 1 hr, something that people seldom do.

This is the thread where people are now about to mash 2hrs/61°C and I think miraculix is planning to start at alpha range, then adding some fresh grain with beta activity and continuing at lower temperature to see if it results in a good fermentability.

 

[dmtaylor]

Okay, now I'm wondering if I should put something else back up there in my *deleted* post! But actually I think most of what has been discussed remains relevant, and my initial response still stands. Anyone who cares to maximize attenuation should run a bunch of experiments with longer mash times to see how much it matters. And if it does matter a lot... then question whether you are crushing hard enough.

I do like the idea of adding fresh malt in the second half of the mash to kick up the beta amylase, that's a great idea.

 

[couchsending]

But isn’t there the variable of too hard of a crush and more potential for tannin extraction/harsh flavors?

 

[dmtaylor]

I think the Goldilocks zone is quite broad. You can do a congress mash if you want, but I'm not advocating that, unless perhaps you are running lab science experiments. If you want something drinkable that won't result in stuck runoff... no.

 

[Miraculix]

Early in my all-grain brewing, I mashed a dozen or more batches to determine the minimum time required for good efficiency and attenuation. I have not experimented with the long mashes, just short ones. What I found is that attenuation is indeed the main variable -- efficiency doesn't change much at all -- and that when mashing for 30 minutes, I could reach my desired attenuation about 50% of the time, but when mashing for 40 minutes, I could get close enough every time, relative to a "standard" 60-minute mash. In recent years now I mash almost every batch for 45 minutes (adding just a small 5-minute cushion of insurance to the 40-figure). I've been making great beer this way for 10 years now. I leave it to others to experiment more with long 2+ hour mashes to determine that effect. In my view, there is a diminishing returns thing with longer mashes but this might be appropriate for beers where you want to maximize attenuation. For most beer styles though... 40 minutes is "good enough" and a taster is less likely to notice a big difference vs. a longer mash.

P.S. I crush the grains hard. There is a lot of flour in my milled grain, and always has been that way. To anyone who doesn't crush hard, they'll likely need to remedy that before running any serious experiments. Poor crush definitely affects efficiency. Crush hard, then efficiency is not variable anymore.

That fits all very well with what I read in a German forum and with how a understand the processes involved (which obviously does not mean that I understand it at all in reality ).

When mashing above 60 degrees celsius, the beta amylase is almost completely gone after 40 minutes. This means that the maximum fermentability should have been reached at this point, as the beta is the main active part in determining how fermentable a wort is going to be. No beta, almost zero increase in fermentability.

One thing I read, which I thought is rather interesting and was new to me, was that a prolonged alpha rest at about 70 to 72 degrees after this 30 - 40 min beta phase can result in a sweeter perception of the residual sugars.

The alpha chops the starch in bigger chunks, long chained sugars. Those longer sugars can than be cut again and again by the alpha resulting in many shorter long chained sugars. Not as short as the beta would provide, but still shorter than the "initial cuts and pieces" the alpha provided. Over time the alpha now created those, let's call them "medium chained", sugars which taste sweeter than the longer counterpart. Still unfermentable, but sweeter in taste.

This means that, according to what I have read, and the forum seemed to agree on it, the 72C rest for a prolonged time (30 to 90 min) can provide the perception of maltiness, body and sweetness to a beer without acrtually increasing the residual sugar, but by modifying it into a sweeter tasting version of it.

 

[RM-MN]

I recall it was the brewers from Two Brothers Brewing giving a speech at one of the homebrew conferences that stated that STARCH extraction and conversion is completed in about 15 minutes of mashing. (ie: the iodine test is negative) However, that freshly converted starch is in the form of long-chain dextrins and sugars. Additional mashing time enables enzymes the opportunity to cleave those long chains into shorter and more fermentable sugars.

Reportedly, Two Brothers 'ends' their mash at 15 minutes, but the additional time necessary to vorlauf, lauter, and sparge the mash probably provides the necessary time for those other enzymatic processes to occur to an acceptable degree. Remember, they are dealing with large volumes and it takes more time than we homebrewers can accomplish with our little systems.

I've used iodine to test for starch with a very fine crush and found that it tested negative for starch in less than 2 minutes. The time for complete conversion is then usually determined by the crush of the grain. If it takes 60 minutes for the mash to complete it is becuase the starches have not yet been completely extracted until then.

I then did a couple batches with a 10 minute mash and found that they had full conversion and attenuated appropriately to the recipe. However, do not do a very short mash as it takes more time for flavors to be extracted from the grains and I ended up with some beer with alcohol but no real flavor. Flavor extraction seemed to be pretty good at 20 minutes so I usually mash for 30 to 40 now.

 

[dmtaylor]

@Miraculix, every word you said is consistent with my understanding, with one possible exception: I wonder if the shorter sugar molecules from the extended alpha rest simply ferment away and lead to a beer that is more dry. The WORT might taste sweeter, but the final BEER might taste more dry? I don't know. More experiments may be needed to know for sure.

 

[Miraculix]

@Miraculix, every word you said is consistent with my understanding, with one possible exception: I wonder if the shorter sugar molecules from the extended alpha rest simply ferment away and lead to a beer that is more dry. The WORT might taste sweeter, but the final BEER might taste more dry? I don't know. More experiments may be needed to know for sure.

I guess not, because the final gravity is the same with and without this prolonged alpha rest. The only difference is the percieved sweetness, at least according to the German forum. Have not tried it myself, but it seemed to be "common knowledge" and it shows up in a lot of recipes there.

 

[Miraculix]

I've used iodine to test for starch with a very fine crush and found that it tested negative for starch in less than 2 minutes. The time for complete conversion is then usually determined by the crush of the grain. If it takes 60 minutes for the mash to complete it is becuase the starches have not yet been completely extracted until then.

I then did a couple batches with a 10 minute mash and found that they had full conversion and attenuated appropriately to the recipe. However, do not do a very short mash as it takes more time for flavors to be extracted from the grains and I ended up with some beer with alcohol but no real flavor. Flavor extraction seemed to be pretty good at 20 minutes so I usually mash for 30 to 40 now.

Keep in mind that the iodine test does only test for starch in solution. The iodine test does not work with already slightly cut starch, which technically is still something like starch but not shown by the test and it does not show starch that is not gelatinised and not in solution. Therefore, the iodine test is not really a good indicator for conversion, although widely used.

 

[MerlinWerks]

HERE is a pretty thorough exploration of a number of mash variables in the quest for maximum fermentability.

I think the takeaway is 75 min @153F...

YMMV

 

[Mer-man]

@dmtaylor, I appreciate you sharing your testing. For a while I was mapping FG and mash temp for my house culture of WLP833. I had a mostly linear relationship on temp to FG, which made it easy to choose a mash temp for a recipe. But this was all at 60 minute duration.

@Miraculix, thanks for the contribution. I will say, make sure your rests are above gelatinization temp for your grain, otherwise a low 60'sC mash won't do your beta much good. It's pretty obvious, and can be tested for in a mini-mash per batch of grain. If you totally miss your extraction, you gotta use a higher temp.
I have had that issue with very cheap grain I was given as a gift; I also had it on a sack of WEY Pils (non-Barke) last year, where I could not mash effectively under 64C.

 

[Miraculix]

@dmtaylor, I appreciate you sharing your testing. For a while I was mapping FG and mash temp for my house culture of WLP833. I had a mostly linear relationship on temp to FG, which made it easy to choose a mash temp for a recipe. But this was all at 60 minute duration.

@Miraculix, thanks for the contribution. I will say, make sure your rests are above gelatinization temp for your grain, otherwise a low 60'sC mash won't do your beta much good. It's pretty obvious, and can be tested for in a mini-mash per batch of grain. If you totally miss your extraction, you gotta use a higher temp.
I have had that issue with very cheap grain I was given as a gift; I also had it on a sack of WEY Pils (non-Barke) last year, where I could not mash effectively under 64C.

Exactly, this is the reason why the very low mash must also be very long, otherwise the starch won't gelatinise properly.

(Forget to mention that main point in my post above, thanks for the reminder)

 

[dmtaylor]

@dmtaylor, I appreciate you sharing your testing. For a while I was mapping FG and mash temp for my house culture of WLP833. I had a mostly linear relationship on temp to FG, which made it easy to choose a mash temp for a recipe. But this was all at 60 minute duration.

Regarding mash temperature effects, different yeasts *might* behave in different ways. The following article from Sean Terrill provides anecdotal evidence. I personally have found some yeasts to be totally unaffected by mash temp, while other yeasts seem to be more affected, so this article is consistent with my experience:

http://seanterrill.com/2017/04/21/observations-on-attenuations/

 

[Mer-man]

Oh I agree entirely -- I was only tracking per yeast strain.

 

[Comfort_Zone]

I mean you can always add amylase directly to help push things along, or use a diastatic yeast. I always mash low though so my experience is usually very high attenuation.