Now the BYO wizard disagrees with me ...

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Kaiser

Kaiser

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... and the German brewing authors I read so far: http://***********/mrwizard/1391.html (2nd topic)

Most likely it was me who was spreading the word on the forum’s that a mash-out at 76 – 78 C (169 – 171 F) doesn’t kill all enzymes and is also not supposed to. I find this in all the German brewing texts that I read so far and even the ones I didn’t read say the same, according to the German homebrew forum.

The interesting thing is, that it doesn’t really matter why you believe the mash-out limit is 170F. The American literature (I have only read homebrewing stuff) seems to suggest that this limit is dure to excessive tannin extraction at higher temperatures while the German authors emphasize that enzymatic activity needs to be preserved in order to convert additional starches that are released by the lauter process. At the end, both views will have you mash-out below 170 and you will be doing the right thing.

I was just surprised to see that even some professionals disagree with what I have been saying in the recent past.

So I’ll have to make an experiment. Mash-out at 170F, hold for 15 min, take a sample of wort and add a little amount of gelatinized starch to it. Just enough to give me an iodine reaction. Keep it at the 170F temp and wait to see if any conversion is happening. This should be fairly easy to do.

Kai



 
Ever since I began homebrewing and reading different literature on the subject, I've noticed that there is a lot of conventional wisdom that seems to have scientific backing that just doesn't. I think this may be due to the level of tradition involved in the process, but there is definitely a lot a pseudoscience out there about brewing.

I read from the beginning about hot-side aeration, trub removal, the importance of secondary fermentations etc. that all have supposedly scientific explanations. In the end, we lack data.

I think this is a great idea, Kaiser, and I'm looking forward to the results. I'm on the side of the German brewers on this one, because if the American explanation were true, then a decoction mash would end in a astringent, bitter mess of a beer.
 
Kaiser said:
[
The interesting thing is, that it doesn’t really matter why you believe the mash-out limit is 170F. The American literature (I have only read homebrewing stuff) seems to suggest that this limit is dure to excessive tannin extraction at higher temperatures while the German authors emphasize that enzymatic activity needs to be preserved in order to convert additional starches that are released by the lauter process. At the end, both views will have you mash-out below 170 and you will be doing the right thing
So I’ll have to make an experiment. Mash-out at 170F, hold for 15 min, take a sample of wort and add a little amount of gelatinized starch to it. Just enough to give me an iodine reaction. Keep it at the 170F temp and wait to see if any conversion is happening. This should be fairly easy to do.

Kai
Click to expand...


I've always wondered about the 170 F limit and the supposed tannin release. If this is indeed a problem, then why aren't decocted beers loaded with tannins? Heck, they're boiled, not kept at 170 F. Does not compute.

As to the experiment, an even quicker and easier way to get a handle is to use salivary amylase. Then you could do the experiment while doing some drinking and kicking back. It won't be as stable, but it may give you and idea,

I'm off to lunch, I'll post some refs. latter. I just found one ref. refering to different isoforms of beta-amylase (that vary in their abundance with the barley variety) and differences in their thermostability. The wimpiest form craps out in 5 min. at 60C, while the most robust is at 20% activity at 15 min. and down to 5% at 20 min.
 
Very interesting Kaiser. This is the part of brewing that I love... hypotheses and scientific experiments. Looking forward to your results. I'm rooting for the Germans... you know, because mein Name ist Menschmaschine!:D
 
menschmaschine said:
I'm rooting for the Germans... you know, because mein Name ist Menschmaschine!:D
Click to expand...

Carful here. I don't want this to be seen as a fight to see who is correct. I waould actually be more intested where the 2 different views are coming from.

...and here I would have guessed it was the drinking really good beer part! :(
Click to expand...

+1

Kai
 
I've been wondering why you don't see more tannin extraction at that point. It's higher phs & temperature that leads to it, i've been told.

Anyways,

sbemail98.png


Science!
 
Kaiser said:
German authors emphasize that enzymatic activity needs to be preserved in order to convert additional starches that are released by the lauter process.
Click to expand...

I'd figure you'd get some conversion, but no where near the conversion you would get holding it at your mash temperature.

It seems like the process would be easier to control by mashing until you've gotten reached the proper conversion and halting conversion, rather than depending on conversion during the lauter process.
 
ClutchDude said:
I've been wondering why you don't see more tannin extraction at that point. It's higher phs & temperature that leads to it
Click to expand...

There was a interesting thread on that on the NB forum: http://forum.northernbrewer.com/viewtopic.php?t=55024&highlight=tannin

The conclusion was, that pH is more important than temperature.

I made Alton Brown's Good Eats home brew recipe (a recipe that calls for boiling the grains as well ;) ) and don't recall it being astringent.

Kai
 
Kaiser said:
I made Alton Brown's Good Eats home brew recipe (a recipe that calls for boiling the grains as well ;) ) and don't recall it being astringent.

Kai
Click to expand...

Interesting, someone recreated that recipe on the green board and said that they found the astringency compensated to a degree for the low dose of hops in the recipe.
 
don't take my word for it. It was my first batch of beer and my palate was certainly not that good. It was just not as awful as one might expect.

Kai
 
As you've already observed, Kaiser, there is a funny thing about brewing lore: it's often correct for the wrong reasons.

Now, that doesn't mean it's always correct! :)


TL
 
brewt00l said:
...and here I would have guessed it was the drinking really good beer part! :(
Click to expand...

That's stating the obvious. I apologize for speaking in absolutes. Let me rephrase: "This is A part of brewing that I love..."
 
Kaiser said:
Carful here. I don't want this to be seen as a fight to see who is correct. I waould actually be more intested where the 2 different views are coming from.
Click to expand...

Same here. My statement was meant in jest.
 
pjj2ba said:
I've always wondered about the 170 F limit and the supposed tannin release. If this is indeed a problem, then why aren't decocted beers loaded with tannins? Heck, they're boiled, not kept at 170 F. Does not compute.
Click to expand...


I am pretty sure that most of the tannins come from the husk of the grain and not the wort. I have never decocted any of my beers so correct me if I am wrong (Please).
 
Chris_Dog said:
I am pretty sure that most of the tannins come from the husk of the grain and not the wort. I have never decocted any of my beers so correct me if I am wrong (Please).
Click to expand...
The husks are boiled in a decoction mash.:eek:
 
Kaiser said:
There was a interesting thread on that on the NB forum: http://forum.northernbrewer.com/viewtopic.php?t=55024&highlight=tannin

The conclusion was, that pH is more important than temperature.

I made Alton Brown's Good Eats home brew recipe (a recipe that calls for boiling the grains as well ;) ) and don't recall it being astringent.

Kai
Click to expand...

Hmmm, this gives me hope. I brewed a Vienna Lager on Monday and wasn't paying enough attention to my sparge water. My sparge was much hotter than it should have been and the grain bed was well over 170° for the length of the sparge, hitting close to 180° at one point. I've been worrying about astringency and won't find out for several more weeks whether or not I sucked a bunch of tannins into my wort. This thread leads me to believe that as long as I didn't over-sparge and allow the pH to rise I might be okay. Thoughts?

Chad
 
Chad said:
This thread leads me to believe that as long as I didn't over-sparge and allow the pH to rise I might be okay. Thoughts?
Click to expand...
I'd say you should be fine. Let us know once the beer is ready.

Kai
 
I was recently listening to a podcast with JZ and I think John Palmer and the take home message seemed to be to have a consistent process whatever you do (mash out or not). You can then adjust your fermentability by changing your mash temp.

GT
 
So how do you guys treat your water? I have a really good water filter, so I don't know that I could get a good idea of what's in it from the City of Chicago water report. I'm thinking I should send out for analysis from a lab. Has anyone done this?
 
Kaiser said:
There was a interesting thread on that on the NB forum: http://forum.northernbrewer.com/viewtopic.php?t=55024&highlight=tannin

The conclusion was, that pH is more important than temperature.

I made Alton Brown's Good Eats home brew recipe (a recipe that calls for boiling the grains as well ;) ) and don't recall it being astringent.

Kai
Click to expand...

This makes perfect sense to me. Mash water naturally tends towards a 5.2 pH after mixing with the grains, meaning that boiling a decoction would not be a problem, while sparge water will have higher pH, which would explain the idea that sparge water can extract tannins.
 
I did the eperiment last night:

* Hold mash out at 169F (76C) for 10 min, which I would consider a proper mash-out
* fill a small vial with a sample of the wort and add some gelatinized starch solution. I gelatinized some wheat flour by boiling it in water
* fill another vial with water and add the same amount of starch
* place both vials into the mash where they’ll quickly take the temperature of the mash and hold it

I tested the iodine reaction of the sample after 10 min and it was significantly less than the one of the contol, but not fully converted yet. After 30 min (end of the lauter) the sample was fully converted:

mash_out_starch_test.jpg


This shows that a mash-out doesn’t kill all the enzymes and that the remaining strength is enough to convert small amounts of starch. Such starch can be released during the lauter or made accessible by the elevated temperature of the mash-out. The latter is the case if the starch doesn’t fully gelatinize during the previous rests.

Kai
 
With enzymes, like women, if you gradually increase the temperature, they will keep working, doing things they might not normally do. Now take some nice confortamble enzyme and abruptly change the temperature and there is a good chance she, I mean the enyzme, will just shut down (denature). This might be the cause of conflicting results. It depends of how quickly you heat to mash out temp and what the previous temp was, the smaller the jump, the more gentle on the enzyme.

Take cooking hard boiled eggs as an example. Put an egg into already boiling water to cook it, and compare the texture of that to an egg that is put in cool water and gradually heated to boiling, and then taken off the heat (the Julian Child way). Rubbery vs creamy.

I did find some references to mashing at elevated pressures. Apparently this leads to even better protein stability at elevated temperatures, albeit at the expense of slightly slower conversion rates, but this was offset by greater protein longevity (good for adjunct conversion).
 
I took the time to reread the article more carefully and found that the Wizard and I are actually more in agreement then I thought we were. I was jumping to conclusions fairly early in the article. He is talking about subsiding activity. I was simply talking about the ability to convert starches if there were more left. He also never said that mash-out denatures all enzymes, only that it brings conversion to a halt because it ends conversion (nothing left to convert).

When it comes to fermentability, this gets basically fixed because b-amylase denatures at these temperatures. Though a-amylase can produce fermentable sugars, it is not very efficient at it and also doesn't have a strong affinity towards shorter dextrines. This is why the mash-out, for all practical purposes, is considered to fix the fermentability of the wort. But the final fixation of the wort composition doesn't happen until the boil.

The issue came up b/c is is actually popular home brewer believe that mash-out denatures all enzymes (I keep reading this a lot whenever mash-out is mentioned). I wanted to use this experiment to show that this is not the case though the outcome has little impact on our brewing practices.

Kai
 

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