Alpha beta

[Julez]

Hi all,

Just trying to wrap my head around alpha and beta amylase and how they interact. In reading Palmer, he notes that sustaining alpha-favouring conditions for longer times de-activates the beta. Does this mean permanently, or if you let the mash temp fall to the beta-friendly range, the beta will re-activate?

Given the higher mash temp leads to a malty sweet beer and lower leads to a drier, more fermentable beer, would starting at a higher mash temp and letting the temp drop to a lower level give you a malty, not quite as sweet, dry beer (all other things held constant, such as mash thickness, pH, etc)?

What is the difference from taking a mash temp from low to high versus high to low in this regard?

Cheers :icon_cheers:

 

[stakka82]

You can't go high to low. When an enzyme is denatured it's gone for good. An enzyme can't perform it's function if it's shape changes, and this is what irreversibly happens when the heat gets too much for an enzyme.

Braukaiser has some great articles about mashing and enzymes. Google braukaiser mash.

 

[manticle]

You can go high to low though - you just can't go too high then expect to recover. You could go from 68 to 62 for example but I find it easier to go 62 -68 to get the results you are interested in.

 

[Mardoo]

Manticle, are you saying that as long as you don't hold the mash at or above the denaturing temp of a particular enzyme you can drop back into their favorable zone and their activity will again increase?

 

[GuyQLD]

Enzymes don't denature instantly, it's a time+temp issue. In theory a short rest at 68 then dropping it to 62 would have some residual beta amalyse remaining. Likewise you get small amounts of alpha activity at lower temps. That's why for single infusion we use 64-66. While working backwards might in theory work manticle is right, go up not down. I think it would take way to much experimenting to work out the backwards method.

 

[Parks]

There was a Basic Brewing Radio podcast on doing exactly this:

Streaming mp3

http://seanterrill.com/2011/03/27/reverse-mashing/

 

[manticle]

Manticle, are you saying that as long as you don't hold the mash at or above the denaturing temp of a particular enzyme you can drop back into their favorable zone and their activity will again increase?

Yes

 

[Yob]

There was a fella came in to the last MB meeting who is a manufacturer of enzymes... man, this guy could talk for days about them, was a very informative session, he indicated as above and the enzyme activity was like a bell curve, past optimal and the activity starts to reduce, it isnt a dead cut off unless you are at denaturing temps which is unlikely (without there being some malfunction / accident)

Interestingly, the fella actually produces alpha and beta enzymes amongst many others.. If I remember correctly, we are going to be getting some 'samples' of a few special ones to play with which will be fun

 

[Julez]

Parks, that was an interesting article. So there may be some merit in a reverse mash after all, provided you don't mash too high or for too long at the higher temp rest, such that you totally denature the beta. The thing I like about this is for those of us that rely on hot water infusions to do temp rests, which then changes the thickness of the mash, it is a lot quicker and easier to get the mash to cool, either naturally or with some encouragement, and get a (potentially) similar result with a lot less mucking about.

Whether there is any perceptible difference in terms of the outcome, compared with just doing a single infusion, will require further experimentation!

Cheers :icon_cheers:

 

[Parks]

Parks, that was an interesting article. So there may be some merit in a reverse mash after all, provided you don't mash too high or for too long at the higher temp rest, such that you totally denature the beta. The thing I like about this is for those of us that rely on hot water infusions to do temp rests, which then changes the thickness of the mash, it is a lot quicker and easier to get the mash to cool, either naturally or with some encouragement, and get a (potentially) similar result with a lot less mucking about.

Whether there is any perceptible difference in terms of the outcome, compared with just doing a single infusion, will require further experimentation!

Cheers :icon_cheers:

Yeah, doesn't experimenting suck :beerbang:

 

[stakka82]

Don't mean to be a cynic, but some pretty high potential to have a batch of wasted beers that don't attenuate below 1025 this way.

There's a reason everyone on Earth does it one way.

 

[QldKev]

The main problem I find with enzyme activity and denaturing points is I cannot find 2 resources that state the same points/values. I use Beta denaturing at 70, and Alpha at 80 which is above what we mash out at.

But since we mash from cold to hot, and repeat mash profiles exact points don't really matter that much.

 

[Yob]

I'll don the old flame suit here... It was my understanding, that beta do not denature at 70 but are past their optimum point and will still be working, just slower.

As I say, it was at a brew club meet, I may have had a few beers, I may have heard it wrong, but that was what I took out of what he was saying, and to some degree makes sense with his bell curve thingamy he showed.. It's my understanding that actual denaturing is ~86'c or something...

er... feel free to blow that apart as misunderstood.. he's left some literature so will see if I can t get a copy next meeting.

 

[QldKev]

Every reference and author seems to have a different version of the ranges, no need for flame suits. Who was it giving the presentation at the brew club?

The Ultimate Almanac of World Beer recipes quotes beta amylase denaturing at 70c. John Palmer in How to Brew quoted 68c but I can't find the reference.
John was also a couple of degrees cooler for the Alpha denaturing than the Almanac.

But I guess it also depends on other factors such as the pH of the wort

 

[stakka82]

Can't give you the exact temperatures but denaturing will happen all along the curve.

Say you have x amount of beta molecules in solution, by 65 or whatever temp at whatever time, half of those molecules will be denatured.

By 70 odd at x amount of time it might be 90%. By 78-80 or whatever at much less time, it will be 100%.

Hence the denaturation 'curve'.

Edit: Also dependent on wort pH as Kev mentioned.

Some of the variation in figures in literature would come from how the denaturation is measured. Do you measure at the 50th percentile mark like with fatal drug doses, or at the 100 percent mark?

After half an hour at 66 degrees half of the beta in solution might be denatured at a given pH. At 80 all are probably denatured.

 

[Mardoo]

Just out of curiosity I had a look at an English brewing text from 1758, in which the author was extolling the virtues of the amazing new tool called the thermometer. (Very cool to see his excitement at using something so utterly common for us.)

I wanted to see how they did their mashes and they mashed at 68 (his readings were in farenheit) for an hour and a half in brick tuns. So, high mash, slow temperature loss. He gave a final wort temperature of 63. Unfortunately the charts were unreadable due to the use of OCR, but he ran many trials and said the temps were pretty consistent.

So, high mash with slow drop has at least some historical precedent. This was from a text I have seen often quoted in a couple early 1800 texts so its likely these were somewhat common practices. Keep in mind they were using these temps well BEFORE anyone knew it was enzymes doing the work in the mash.

Of course this says nothing about the quality of the beers they were brewing or whether we would like them. But it was, at one time, established practice for a number of reasons. At the very least it's kind of interesting! To a geek like me that is .

 

[Byran]

This diagram I found somewhere shows a broad range for each enzyme group and how they overlap . I always wondered if they worked in reverse such as when your mash temp dropped slowly from the step temp.

 

[technobabble66]

+1 to stakka, & Yob.

Enzymes operate/function over a bell curve. They will also denature over another bell curve. (all with respect to Temp, & to pH).

That chart you posted, Bryan, is for the functionality of the various enzymes. The regions indicated for each enzyme is probably where the functionality of that enzyme is above, say, 75%. It's a great way of showing the enzyme action in a mash under variable temp & pH. ^_^

It would be reasonable to guess that just above each "functional region" in that graph, there would be a similar "denaturing region" of that enzyme. (ie: with regards to temp - no idea what pH is required to denture enzymes).
However, i'd have no idea of the specific temp range/threshold of the denaturing region for Beta & Alpha. I just assumed Palmer was correct with 68°C for Beta.

my 2c

**************
What should be the flavour result of dropping the temp during mash, then? Say, from 67°C to 63°C.
My understanding is that the Alpha would free-up more of the starch as long chain oligosaccharides, then as the temp comes back into Beta-range the Beta will rip up both regular starch, plus all those longer oligosaccharides. So that should result in a dry, highly attenuated beer, shouldn't it? :huh:
Wouldn't that mean all the benefits from a high mash (eg: bigger mouth-feel, malty & sweeter flavour) are removed by the Beta?
So could that explain why Mashing involves increasing the temp, rather than going the other way - because going the other way removes all benefits of the initial higher temp?? :blink:

 

[Byran]

So if the higher mash temps attribute a sweeter flavour with more mouth feel does this translate into maltyness? Or just sweetness in general?
I always seem to find the balance of a beer is affected if too sweet or dry and I always find that if too much alcohol flavours are present then its not great. So I guess alpha and beta amylase must be balanced to suit style. Which everyone must taste to some degree. I just still seem to be learning the "right " balance.

 

[manticle]

Forget sweetness. Dextrins aren't especially sweet.

 

[toncils]

Dunno if this is a dopey question, but if you were to denature the enzymes, wouldn't you still be left with heaps of starch resulting in a high OG?

For example, I did a brew on an unfamiliar setup last week, left the gas too high and found it around 80 degrees. Pulled the temp down as quickly as possible, then threw some wheat malt in hoping to replace some enzymes. Anyway, my OG was at 1034; around 25% efficiency.
Why would the starches not affect the gravity?

 

[HBHB]

80 degrees is high enough to degenerate the enzymes in short order. Thus within minutes, they'd be pretty much screwed. Plus the wheat malt will only really have sufficient enzyme to convert itself, nothing more.

 

[stakka82]

Why would the starches not affect the gravity?

Probably showing my ignorance too but I don't think that's a stupid question. Often wondered that too.

 

[toncils]

hah...Forums can be a minefield.

Also, do some base malts have more enzymes than others?

 

[stakka82]

Yeah, referred to as the diastatic power of the malt.

 

[Mardoo]

You bastards. I'm not going to be able to sleep now. :blink:

SG measures something like relative density of the wort compared to water, so if there is less sugar and more starch what will the effect be? Pure guess says to me that most starches are less dense than sugars.

Started getting into DeClerck to find an answer but my head is far too fuzzy at this point to read texts on analytical purposes and methods. See? Just saying that hurts. :wacko:

 

[toncils]

Anyone else have some light to shed on this investigation?

 

[manticle]

My understanding is that sg is a measurement of the potential sucrose in solution. Sucrose will increase gravity more than any other starch or sugar and will dissolve readily.
If not converted, starch will add to sg but dissolves less readily (still dissolves in hot water though) and contributes less to the gravity.
I'll hunt up some references when not on a phone but google byo gravity starch for an article.

Short answer - yes starch contributes to gravity but less so than shorter chain sugars.

 

[toncils]

Aha, makes sense, but goes against my expectations- time to get a degree in chemical engineering. Thanks for that, Manticle