Mash Temp: Differences Between the Upper and Lower Ends of the Normal Range?

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GrowleyMonster

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So I see a lot of different mash temps used, from about 140° up to about 158°, and I gather that the same mash bill can give rather different results at one end of that range, vs the other end. Can someone summarize this for me, so I can narrow down my target mash temp?

My basic 5gal recipe:
10 lb 2-row pale malt
1 lb 350 chocolate malt
1 2-1/2 lb cannister Quaker quick oats
Planning to add a half pound, maybe a pound, of a crystal malt from Viking called Cookie Malt, 15.6-23.1 °L
Also contemplating a small addition of lactose.
Hopping is low, an ounce or at most two ounces of basically whatever I have on hand or what is on sale, added in the boil. I don't care for nor appreciate hoppy beers, just going through the motions on hops, you could say. Mostly it is Cascade or Helga or Sasz.
Yeast is likewise variable but mostly BE-134 currently, sometimes BE-256 I think, occasionally Voss Kviek if there is a power outage from a hurricane or other issue forcing me to ferment at higher temps than air conditioned room temp.

I have been stirring in the oats first at about 160, then after 15 minutes, an equal amount of the pale malt, and after 15 minutes the rest of the fermentables. As it cools I monitor and hold at 145 or above for another hour, then pulling the bag and squeezing, and sparging the bag with another 2 gallons of very hot water, and squeezing it as dry as I can get it when it is cool enough to handle. Of course this works, and works well, but I am curious about what I should expect from holding mash temp higher, or letting it slide lower.

Does it really even make a noticeable difference in taste and mouth feel? It is kind of hard for me to make comparisons from batch to batch. I only have capability of having one keg on tap at a time and I don't bottle.
 

Beholder

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The enzyme activity temperature ranges vary, and while there isn’t a definitive line in precise temperature limits, alpha enzyme is activated in the higher temperature range you mention, which converts the sugars to more unfermentable versions ending with more body and higher FG, which would work well for the style you are brewing. Since you start high and drop lower over time, you likely won’t see the effects of the lower temperature since most conversion may have already happened.

For other styles, e.g. German lagers, where crisp light taste is hallmark, the mash temperatures and their control is more critical. In my experience, I can still produce a good beer with a single temp infusion, but I can get a great beer by step mashing through the lower temperatures even with today’s well modified malts.

To read up further on it, a good overview can be found athttps://www.homebrewersassociation.org/how-to-brew/enzymes-in-beer-whats-happening-in-the-mash/
 

dmtaylor

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In truth, there is a Goldilocks range for mash temperature which goes between approximately 148 to 156 F. If you mash anywhere in that temperature range, you're really not going to have any problems. I usually aim for 150-152 F for most beers and don't try to overthink mash temperature, because it doesn't really matter as much as mash TIME.

That's right. Concern yourself more with mash TIME.

If I want a fuller bodied beer, I might mash for a shorter time of just 30-40 minutes. And if I want a really dry and well attenuated beer, I'll mash for 75-90 minutes, or even more for something like a saison where I might want it to finish at 1.000-1.002.

People get all bent out of shape overthinking mash temperature. In reality, it just DOES NOT MATTER THAT MUCH, as long as you're within that Goldilocks range where the enzymes aren't all getting destroyed. Once temperatures get up into the 160s to 170 F or more, the enzymes are denatured very very quickly and it can hurt fermentability. And if temperature is too low, the enzymes are not denatured but will act very very slowly. Keep it in range, though, and you're fine.

So I'm a big advocate for playing around with mash TIME more than anything else. I've done over a hundred batches and toyed with mash time as the variable dozens and dozens of times. For many years, I've been mashing almost every beer for 40-45 minutes. I've found that for me, on my system, this mash time gives me consistent efficiency and attenuation without wasting 60-90 minutes of my life but only ~45 minutes -- why not save a few minutes and get to bed 15 minutes earlier or whatever. YMMV.

For the particular batch mentioned by the OP, with oats and possibly with lactose.... well if you use lactose, then mash temperature really doesn't matter much at all, the lactose will overpower whatever you do in the mash, or can help fix it if the beer turns out too dry. I don't like to use oats because they are a sticky mess. In this case, I might suggest a glucan/protein rest of 112-122 F for 10-15 minutes to help break down some of that, then step up to the typical ~152 F (middle of Goldilocks range) for another 45-60 minutes, and call it good. Doesn't need to be complicated.
 
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GrowleyMonster

GrowleyMonster

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The enzyme activity temperature ranges vary, and while there isn’t a definitive line in precise temperature limits, alpha enzyme is activated in the higher temperature range you mention, which converts the sugars to more unfermentable versions ending with more body and higher FG, which would work well for the style you are brewing. Since you start high and drop lower over time, you likely won’t see the effects of the lower temperature since most conversion may have already happened.

For other styles, e.g. German lagers, where crisp light taste is hallmark, the mash temperatures and their control is more critical. In my experience, I can still produce a good beer with a single temp infusion, but I can get a great beer by step mashing through the lower temperatures even with today’s well modified malts.

To read up further on it, a good overview can be found athttps://www.homebrewersassociation.org/how-to-brew/enzymes-in-beer-whats-happening-in-the-mash/
Okay so now I can relate to it a little better. I was seeing alpha, beta, this and that, but I wasn't connecting to a final result. And now I see that a higher temp leaves more residuals in the final beer, higher fg, more body, less dry. Cooler results in lower FG, crisper and dryer end result. Exactly the sort of answer I am looking for. Thanks. You have just added significantly to my practical knowledge of brewing.

With all the fermentables in the bill, I don't really have to worry about ABV. I WILL get plenty of alcohol. So maybe I should try to hold the final mash temp between about 150 and 156. Heat source is a propane crawfish boiler, no thermostatic control. Precision then, is something I am glad to see most brewers think is not so important in mashing temperature.
 
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GrowleyMonster

GrowleyMonster

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In truth, there is a Goldilocks range for mash temperature which goes between approximately 148 to 156 F. If you mash anywhere in that temperature range, you're really not going to have any problems. I usually aim for 150-152 F for most beers and don't try to overthink mash temperature, because it doesn't really matter as much as mash TIME.

That's right. Concern yourself more with mash TIME.

If I want a fuller bodied beer, I might mash for a shorter time of just 30-40 minutes. And if I want a really dry and well attenuated beer, I'll mash for 75-90 minutes, or even more for something like a saison where I might want it to finish at 1.000-1.002.

People get all bent out of shape overthinking mash temperature. In reality, it just DOES NOT MATTER THAT MUCH, as long as you're within that Goldilocks range where the enzymes aren't all getting destroyed. Once temperatures get up into the 160s to 170 F or more, the enzymes are denatured very very quickly and it can hurt fermentability. And if temperature is too low, the enzymes are not denatured but will act very very slowly. Keep it in range, though, and you're fine.

So I'm a big advocate for playing around with mash TIME more than anything else. I've done over a hundred batches and toyed with mash time as the variable dozens and dozens of times. For many years, I've been mashing almost every beer for 40-45 minutes. I've found that for me, on my system, this mash time gives me consistent efficiency and attenuation without wasting 60-90 minutes of my life but only ~45 minutes -- why not save a few minutes and get to bed 15 minutes earlier or whatever. YMMV.

For the particular batch mentioned by the OP, with oats and possibly with lactose.... well if you use lactose, then mash temperature really doesn't matter much at all, the lactose will overpower whatever you do in the mash, or can help fix it if the beer turns out too dry. I don't like to use oats because they are a sticky mess. In this case, I might suggest a glucan/protein rest of 112-122 F for 10-15 minutes to help break down some of that, then step up to the typical ~152 F (middle of Goldilocks range) for another 45-60 minutes, and call it good. Doesn't need to be complicated.
So a protein rest is BEFORE raising kettle temp to the mash range? And you would add the other fermentables before this protein rest, or after heating to mash temperature? And if mash time is critical, is the mash terminated by cooling below the lower end of the range, or exceeding the high end as the wort is heated to boiling?

I am using BIAB and I stir constantly while adding fermentables, not troubled by clumps or lumbs or dough balls, no worries over stuck sparges. I usually hoist the bag above the kettle and leave it hanging while I light the burner for the boil. I sparge once with a gallon and a half to two gallons near boiling water and squeeze it good when it is cool enough to handle, then add it to the boil. I am kind of used to not having this protein rest, but will it make life easier for me, and more importantly, will it improve the beer? I will certainly try it if there is something to be gained from it.
 

Holden Caulfield

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So I see a lot of different mash temps used, from about 140° up to about 158°, and I gather that the same mash bill can give rather different results at one end of that range, vs the other end. Can someone summarize this for me, so I can narrow down my target mash temp?
Temperature and time have the greatest effect on the fermentability of the wort. The more fermentable the wort, the lower the finished gravity, the drier, and the less chewy (mouth feel) the beer will be.

There are two primary enzymes that break the starches in the malt into sugars - Beta and Alpha Amylase. Beta breaks down the starches by biting off fermentable sugars at the ends of the the starch molecules and Alpha breaks down the starches by cutting the branches off the starch molecules making more ends for the Beta to work on. Alpha denatures (stops working) at much higher temperatures than Beta. Beta begins to denature around 150 and rapidly denatures after 160 - the denature rate gets progressively faster as the mash temperature rises.

For single infusion mashes, you can alter the time and temperature to alter the fermentability of your wort. For example, you can make highly fermentable wort by mashing below 150 as the Beta keeps working, albeit at a slower pace, and mash for a long time - 148 for 90 minutes will really dry out the beer provided you don't add a lot of unfermentables like lactose. Alternatively you can mash higher for the standard 60 mins and obtain a less fermentable wort. For example, 152 for 60 mins will provide a standard (some may say more fermentable) wort fermentability profile. Finally, If you were to mash at 158, the Beta would denature rapidly and you would end up with a fully converted but less fermentable wort.

There is no perfect predictor for what to expect but great minds like Braukaiser have done analysis to put data around what to generally expect as there are too many variables (grain bill, temp, time, yeast, PH, etc) to predict the exact FG for your beer. Below is a graph that characterize the relationship between temperature and fermentability for 60 min single infusions - it includes data from a few sources.

Bottom line, generally, 148 to 152 will result in the most fermentable wort for a 60 min mash. For less fermentable wort, target 154+ for 60 mins. For highly fermentable wort, target 149 and below for 60+ mins. Note, others may shift the ranges based on their experiences and preferences, only your personal experiences will provide you with what mash temperature and time suits your definition of dry, sweet, chewy, etc.

1635089489773.png
 

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dmtaylor

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So a protein rest is BEFORE raising kettle temp to the mash range? And you would add the other fermentables before this protein rest, or after heating to mash temperature? And if mash time is critical, is the mash terminated by cooling below the lower end of the range, or exceeding the high end as the wort is heated to boiling?

I am using BIAB and I stir constantly while adding fermentables, not troubled by clumps or lumbs or dough balls, no worries over stuck sparges. I usually hoist the bag above the kettle and leave it hanging while I light the burner for the boil. I sparge once with a gallon and a half to two gallons near boiling water and squeeze it good when it is cool enough to handle, then add it to the boil. I am kind of used to not having this protein rest, but will it make life easier for me, and more importantly, will it improve the beer? I will certainly try it if there is something to be gained from it.
If you do any step mash, you need to start at the lower temperatures and work your way up, because above different thresholds, different enzymes in the malt become denatured, which means if you raise temperature and then bring it back down, it's too late, the enzymes are gone. So you always want to move towards warmer temperatures. Alpha amylase is the last to be killed off, around 168 F. About 5-10 minutes at that temperature or more marks the end of enzymatic activity for all intents & purposes. There is much more that could be said about mashing... and if you are interested, you can Google it online. Howtobrew.com might be a good place to start. You can & should mash all the grains together, everything.

I am not normally an advocate of step mashing at all. Normally I frown upon protein rests with 21st century malts as it can turn the beer watery with thin lifeless head retention. So I do single infusion mashing 95% of the time. Exceptions are when I want to break down the gummy glucans or proteins such as an oat beer, or might also do this with rye which can be just as gummy if not more than oats. That being said...... with BIAB, you can safely skip the glucan or protein rest(s) if you wish, with no real adverse effects except that the bag may take longer to drain than normal. What can also help with the gumminess is adding 1 lb rice hulls. Rice hulls are a very common way to minimize the gummy stuck runoff.
 

Falstaff

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So I see a lot of different mash temps used, from about 140° up to about 158°, and I gather that the same mash bill can give rather different results at one end of that range, vs the other end. Can someone summarize this for me, so I can narrow down my target mash temp?

My basic 5gal recipe:
10 lb 2-row pale malt
1 lb 350 chocolate malt
1 2-1/2 lb cannister Quaker quick oats
Planning to add a half pound, maybe a pound, of a crystal malt from Viking called Cookie Malt, 15.6-23.1 °L
Also contemplating a small addition of lactose.
Hopping is low, an ounce or at most two ounces of basically whatever I have on hand or what is on sale, added in the boil. I don't care for nor appreciate hoppy beers, just going through the motions on hops, you could say. Mostly it is Cascade or Helga or Sasz.
Yeast is likewise variable but mostly BE-134 currently, sometimes BE-256 I think, occasionally Voss Kviek if there is a power outage from a hurricane or other issue forcing me to ferment at higher temps than air conditioned room temp.

I have been stirring in the oats first at about 160, then after 15 minutes, an equal amount of the pale malt, and after 15 minutes the rest of the fermentables. As it cools I monitor and hold at 145 or above for another hour, then pulling the bag and squeezing, and sparging the bag with another 2 gallons of very hot water, and squeezing it as dry as I can get it when it is cool enough to handle. Of course this works, and works well, but I am curious about what I should expect from holding mash temp higher, or letting it slide lower.

Does it really even make a noticeable difference in taste and mouth feel? It is kind of hard for me to make comparisons from batch to batch. I only have capability of having one keg on tap at a time and I don't bottle.
Your fg will be different. All of my beers that I mashed super high, like 160, stalled at 1.02.

A brulosophy experiment seemed to show that 1.02 and lower is pretty imperceptibly different, and I can confirm this.

1.02 and lower never tastes sweet to me. Just know that it will finish high, but also that it probably doesn't matter all that much.
 
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GrowleyMonster

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Thanks for all the replies. I am coming away from this thread with a little better idea of what to expect from different mash regimens and a little better idea of how I want to do it, exactly, which was my goal. Your sharing of knowledge is much appreciated.
 
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