Mash enzyme question w descending mash temp

[Dland]

If one mashes in at higher temp, say 155F, and lets mash slowly cool to in the course of an hour to around 145, if mash is then let to rest longer at the lower temp, does the beta amylase break down longer sugar chains produced by alpha amylase earlier in mash? Or do betas just convert starches to sugars.

I kind of feel I should already know this, but was never clear on that.

 

[Red over White]

This works quite well for producing a highly fermentable wort. With the malt above gel temperature and alpha activity happening, beta has plenty to do.

 

[Holden Caulfield]

Short answer - both beta and alpha convert starches to sugars.

Descending step (or continuous) mash schedule are not the norm - I have never read about one, but that does not mean they don't exist. Although, as a homebrewer I lose 2 degrees per hour, but this is due to limitations of my system rather than ideal.

Alpha amylase prunes the branches off the starches and make more ends for the Beta Amylase to crack off fermentable sugars. The problem with starting in the mid 150s is that the Beta Amylase is denatured quickly, so that while there are more ends, there is far less Beta to work on them. It is for these reasons that step mashes start at lower temperatures and then are raised, as the fermentability of wort is set in the 145 range and time period, and then full conversion with a little more fermentability is finalized above the 155 range. Below are charts of Beta and Alpha amylase denature times and temperature (source: Braukaiser.com).

That said, if you mash starts at 155, you will end up with a good conversion, just not a highly fermentable one.

 

[Bassman2003]

This is a great mash tactic for highly fermentable wort, just do not hang out in Alpha very long in the beginning. Dough in and immediately let it fall to beta then eventually go up to alpha as usual. All of these processes are natural, so they take some time to play out and do not truly go to zero. So you can bend some rules, just like Neo in "The Matrix"

 

[Red over White]

Mashes that start with a higher degree lintner, have more to contribute over time too.

 

[Holden Caulfield]

This works quite well for producing a highly fermentable wort

This is a great mash tactic for highly fermentable wort,

^Building upon...

The most fermentable worts, ones that achieve high attenuation and low finished gravity, the optimal strategy is to ferment below 148ish for a very long time (90 mins+). The alpha will continue to prune branches as it is not denatured, and the beta will bite off fermentable sugars off all the ends while not being denatured, allowing it to work a long time.

Any temperature above 150 will begin the Beta denaturing process. For a single infusion 1 hour mash 149-152 is about the sweet spot to produce the most fermentable worts, above this there is a decline that accelerates above 154. See chart below.

In other words - targeting 155 to start a mash and letting it drop to 145 over the course of an hour is not an ideal strategy for making the most fermentable wort. While I have no empirical data on this type of mash, given that the mash would be above 152 for about 15 mins, I would guess that it would probably produce a wort that is 1-2% less than max attenuation for a 60 min single infusion. If the goal is to achieve very high attenuation it would fall short relative to other mash schedules.

 

[Dland]

Thanks for the replies. I'm pretty aware of the roll mash temp plays in fermentability, I just was not that clear on the exact science. Esp pertaining to whether Betas broke Alpha produced sugars down.

I mashed in a little higher than normal today, 154F, usually shoot for 150-151, and I loose several degrees over course of a 70 min mash. I used to mash in around 145-148F for drier beers, but was wondering if I was loosing a little efficiency due to not getting mash hot enough to "gelatnintize".

Today my strike water was just a little hot and did not want to wait for it to cool again, been brewing every week for a while maybe getting a little sloppy, ;}. I ran on vorlauf (recirculate) for a bit to bring it down some after doughing in.

Learned a new word today too, lintner=diastic potential. Mash was 75% Pils, 12,5% Vienna, 12.5% rye malt, so lintner probably pretty good, and recipes like this tend dry anyway.

 

[VikeMan]

Learned a new word today too, lintner=diastic potential. Mash was 75% Pils, 12,5% Vienna, 12.5% rye malt, so lintner probably pretty good, and recipes like this tend dry anyway.

Just to fine tune your new vocabulary a little, Degrees Lintner is the unit used to measure diastatic power. Like the way the gram is used to measure/describe mass.

 

[Bassman2003]

The mash I was referring to would have a dough-in in the low 150's then without applying heat, let the mash sink down into the 140's then proceed as usual. So not much time spent above optimal beta to cause much harm.

 

[dmtaylor]

The trouble with mashing in at 155 F then letting the temperature fall to promote beta amylase is that the beta is essentially all gone in the first 10 minutes at 155 F. Your alpha amylase will keep on working as the temperature falls, but the beta is denatured. The alpha can improve fermentability and attenuation, but it won't be from the beta if you do it this way.

 

[ScrewyBrewer]

As a rule, setting your mash temperature should happen within the first 10-20 minutes of the mash. Temperature changes made after that have little effect on fermentability.

 

[Red over White]

Step down mashing can be done a number of ways. If you look at COA's you have a pretty good idea of the gel temp to hit and then you can add reserved cold water to step down immediately. After mashing for a bit you can add the last 10-15% of the grist like a pils or 6 row and extend your beta rest even longer.

I like to have my strike water at 142°F and dough in, it will drop to low 130's and then slowly heat to 149 and let it step down from there (a fan pointed at the mashtun does a great job quickly while recirculating). This gives limit dextrinase some time, before alpha and beta do their thing. I mash longer than most are willing to but, mashing for high attenuation isn't a quick process and I can't rush it.

 

[VikeMan]

The trouble with mashing in at 155 F then letting the temperature fall to promote beta amylase is that the beta is essentially all gone in the first 10 minutes at 155 F.

I suppose if one is starting with a low diastatic power mash, it might be fair to say that the beta amylase is essentially gone, in practical terms, at 10 minutes at 155F.

At any given temperature, amylase enzymes denature in a half-life fashion, like so many physical processes. Of course, how much diastatic power (in degrees lintner) survives after "X" minutes depends very much on how much you start with. e.g. a Pilsner Malt mash will have a lot more power relative to a Maris Otter mash, for any given amount of time passed.

I have derived approximate formulae for alpha and beta denaturing, based on (other peoples') research data and a discussion (about interpretation of the data) in another forum. The Beta estimate looks like this (in excel format):

=9460*EXP(-0.098*((A1-32)*5/9))

...where the A1 cell is the temperature in degrees F. At 155F, this formula yields a half-life of ~11.7 minutes. So at 10 minutes, by this estimate over half of the Beta Amylase would still be around. At 23.4 minutes about 25% of the Beta Amylase would survive.

Formulae aside, the point I want to make is that amylase enzyme denaturing happens in a half-life fashion and that the amount of beginning DP has a very direct bearing on how much enzyme will still be around at a given time in the mash.

 

[Bassman2003]

Good points. This is very system dependent. I would say starting in beta is the most obvious way to mash, but this can be below gel temps for certain malt or years of crops. So starting a little higher for the dough-in can be a tactic that yields good results. Just answering the OP's post. That does not mean mash in at 155F and let it sit there for 15 minutes and then ramp down just to be clear for anybody reading this in the future.

I have been using distillers malt for more attenuation which provides more enzymes resulting in better use of the beta rest. But longer time spent in beta is a good practice for 1.008 and under attenuation.

 

[dmtaylor]

I have derived approximate formulae for alpha and beta denaturing, based on (other peoples') research data and a discussion (about interpretation of the data) in another forum. The Beta estimate looks like this (in excel format):

=9460*EXP(-0.098*((A1-32)*5/9))

...where the A1 cell is the temperature in degrees F. At 155F, this formula yields a half-life of ~11.7 minutes. So at 10 minutes, by this estimate over half of the Beta Amylase would still be around. At 23.4 minutes about 25% of the Beta Amylase would survive.

Formulae aside, the point I want to make is that amylase enzyme denaturing happens in a half-life fashion and that the amount of beginning DP has a very direct bearing on how much enzyme will still be around at a given time in the mash.

Very cool. I was wondering if anyone had yet developed a formula like this. So a bit of the beta will last quite a while longer than I had estimated. On the other hand, there ain't much left after the first 30-35 minutes unless the temperature drops really fast. Or, like you say, if you use a lot of high diastatic malt. That all makes sense. Thanks.

 

[CascadesBrewer]

...where the A1 cell is the temperature in degrees F. At 155F, this formula yields a half-life of ~11.7 minutes. So at 10 minutes, by this estimate over half of the Beta Amylase would still be around. At 23.4 minutes about 25% of the Beta Amylase would survive.

My understanding is that grain crush can have a large impact on how fast enzymes are denatured.

I do a number of 2.5 gallon batches (full volume BIAB) and I usually expect about a 5-6F degree drop over my typical 60 minute mash. While I don't have targeted data about starting mash temp and attenuation, I definitely feel that starting mash temp has a strong impact on my attenuation. If I mash in at 154F and that temp drops to 149F over 60 minutes, I will generally expect attenuation to be in line with a 154F mash temp. Where if I mashed in at 150F, I would expect more attenuation.

If one mashes in at higher temp, say 155F, and lets mash slowly cool to in the course of an hour to around 145

I would be curious to see an experiment on this. My gut says the resulting attenuation would be similar between this dropping temp mash and one that was held at 155F for the duration (or maybe held at 153F).

 

[Bassman2003]

I mash in an Anvil Foundry with recirc and my temps will fall if I do not have the heat on. So my approach or view is with a fairly descending mash temp. If your tun does not fall very much on its own, then this mash program loses viability for sure.

 

[VikeMan]

My understanding is that grain crush can have a large impact on how fast enzymes are denatured.

Grain crush could certainly impact the time it takes to get the enzymes into the brewing liquor. So you could say that the "countdown" clock starts sooner or later, depending.

 

[HighVoltageMan!]

Listening to a Master Brewers Podcast with Joe Hertrich, he mentioned that Weinhenstephan did a series of mashes looking for the most fermentable wort. 65C (149F) was the optimum temperature. In roughly 15-20 minutes 90% of the conversion was complete, over the next 45 minutes (1 hour total) it was at full conversion. Starting at 155 and lower it seems to be counter productive because of the denaturing of beta amylose.

The other part of the mash equation is the pH. A pH of 5.6 at room temperature (@5.4 at mash temperature) seems to be the best for conversion in my experience.

 

[CascadesBrewer]

Any temperature above 150 will begin the Beta denaturing process. For a single infusion 1 hour mash 149-152 is about the sweet spot to produce the most fermentable worts, above this there is a decline that accelerates above 154. See chart below.

Correct me if I am wrong, but I do recall seeing data that a (rising temp) step mash can produce a more fermentable wort than a single temp mash.

I don't do step mashes myself since they are a pain with my setup. I am fairly happy with the level of attenuation I can get with a 149F mash for 60 minutes. For higher gravity Belgians, I will include simple sugars in the recipe to help drive attenuation.

 

[dmtaylor]

Correct me if I am wrong, but I do recall seeing data that a (rising temp) step mash can produce a more fermentable wort than a single temp mash.

I don't do step mashes myself since they are a pain with my setup. I am fairly happy with the level of attenuation I can get with a 149F mash for 60 minutes. For higher gravity Belgians, I will include simple sugars in the recipe to help drive attenuation.

What I truly believe matters most, within the goldilocks zones for different enzymes, is not the exact temperatures or steps involved, but rather the TOTAL mash TIME. As discussed previously, beta is active for a while at lower temperatures, and alpha just keeps on chugging at any temperatures up to 168 F.

So... while I might not have hard data backing up my hypothesis, I would expect a fancy step mash where all the step times add up to 90-120 minutes or whatever to attenuate about the same as a standard single infusion mash where the temperature is held at a steady 149 F or thereabouts for the same 90-120 minutes. The illusion here is that a step mash improves attenuation by a good margin... but what if the steps are short such that the total step-mash time only adds up to the same 60 minutes as a standard single infusion mash? Hmm. Overall I find it much easier to do single infusion, and I'm willing to bet a 6-pack that no one can taste a difference, and the FGs would be within a point of one another anyway, as long as the total mash TIMES are the same... also assuming all reasonable temperatures in standard ranges with enzymes doing what we expect them to do, not doing something wonky where we kill off the beta too early.

 

[Dr_Jeff]

I heard part of a podcast where Jamil was talking and he also said that 149 was the sweet spot and he tried to mash most of his beers at that temperature.

Since then I have always shot for 149.

 

[dmtaylor]

I heard part of a podcast where Jamil was talking and he also said that 149 was the sweet spot and he tried to mash most of his beers at that temperature.

Since then I have always shot for 149.

I've always shot for 150 F. "Nice round number." Good enough for Dr. Emmett Brown, good enough for me.

 

[Dr_Jeff]

I wonder how it would go, if one crushed up a Beano tablet or two and added it to the mash.

 

[dmtaylor]

I wonder how it would go, if one crushed up a Beano tablet or two and added it to the mash.

Or halfway into the mash, after the beta is gone? Might help, in theory. I forget what the exact enzymes are in Beano, but they're very plentiful and effective, at lower temperatures anyway (not denatured), I do recall that.

 

[Dr_Jeff]

Or halfway into the mash, after the beta is gone? Might help, in theory. I forget what the exact enzymes are in Beano, but they're very plentiful and effective, at lower temperatures anyway (not denatured), I do recall that.

According the Google machine it is alpha-galactosidase whatever that is.

 

[Dr_Jeff]

I guess that since it works in your gut, it could also be added to the cooled wort.

 

[Dr_Jeff]

calling @bracconiere for input

 

[Dland]

I would be curious to see an experiment on this. My gut says the resulting attenuation would be similar between this dropping temp mash and one that was held at 155F for the duration (or maybe held at 153F).

I've appreciated reading the replies to my inquiry. I garnered info on how process works, which is good. I knew my strike water was a little warm for my normal process, but sent it in anyway, was in a hurry to mash in since I had some other stuff to do.

As for an experiment, I have a couple previous batches that are have similar grain bills, one just crashed, the other spunding, mashed in at 151 and 150 respectively. I'll check out final gravities on these three and compare. Same yeast as they are in cone to cone series. Will report findings in this thread.

 

[bracconiere]

calling @bracconiere for input

i saw it, and then the forum...

i'm banned from brew science...i was going to post this and try and work on my logarythmic charting skill to see if i could convert all the into percentages for you dland. but i still strugle with a calculator and trig...

so at a 155f mash for an hour, you'd still have 30% beta activity left i think.. and as far i know the reason there IS a brewers window is you have to use the alpha to soften the starches up for the 'beta enzyme'?

if i was doin what i think is being proposed...i'd do a step at 149f, then ramp up to 155f? i'd 'guess' slowly cooling with only 30% activity left...