Author Topic: Barley Gelatinization  (Read 1088 times)

Offline jeeyeop

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Barley Gelatinization
« on: January 06, 2016, 11:01:14 PM »
So I was reading that barley gelatinizes at about 140-144F. You need gelatinization in your grains for the starches to be more readily accessed by the amylase enzymes. I'm just curious. Would boiling barley before setting the wort back into the 150-160F range affect the starch conversion rate significantly? For example, would it harden the exterior or anything to make the starches less accessible for the amylase enzymes? This is just out of curiosity as I would never do this since the tannin extraction would be insane.

On a related note, can someone just confirm that the reason we don't have our saccharification rest at 140-144F is because there are more alpha amylase enzymes in barley rather than beta? That and you'd be breaking down a lot of dextrines at those temperatures. Thanks! -Justin

Online hopfenundmalz

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Re: Barley Gelatinization
« Reply #1 on: January 06, 2016, 11:16:33 PM »
You should read about decoction mashes. The thick part is boiled, which explodes the small starch granuales that the enzymes can't get into. The enzymes are inthe thin (liquid part) that is left behind. Tannin extraction is not too much of a problem at the pH of the Mash.

If you look at spec sheets, there is more Beta than Alpha. Step mashes spend time in the 144-146 range where Beta is most active, then you go to 158 to 160 for Alpha.

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Offline mabrungard

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Re: Barley Gelatinization
« Reply #2 on: January 07, 2016, 02:36:20 PM »
Yes, there is that problem in getting the starch out of the grain kernel. However, you can't boil the base malt before mashing since that would denature the enzymes needed for starch conversion. Exposing more of the kernel surface area via finer milling is one way to improve extraction. An additional consideration is that the mashing process should extract more of the starch if the mashing temperature is eventually brought to a fairly high temp such as 168F as part of a mash out step.

Jeff, while I agree that pH can play a part in tannin extraction, I still believe that its the high wort gravity and the osmotic stress it places on the remaining husk and kernel matter that helps limit tannin extraction during decoction. We can keep pH low throughout sparging, but if you let the final wort gravity get too low, you will extract tannins from the bed.   

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Re: Barley Gelatinization
« Reply #3 on: January 07, 2016, 03:13:24 PM »
Yes, there is that problem in getting the starch out of the grain kernel. However, you can't boil the base malt before mashing since that would denature the enzymes needed for starch conversion. Exposing more of the kernel surface area via finer milling is one way to improve extraction. An additional consideration is that the mashing process should extract more of the starch if the mashing temperature is eventually brought to a fairly high temp such as 168F as part of a mash out step.

Jeff, while I agree that pH can play a part in tannin extraction, I still believe that its the high wort gravity and the osmotic stress it places on the remaining husk and kernel matter that helps limit tannin extraction during decoction. We can keep pH low throughout sparging, but if you let the final wort gravity get too low, you will extract tannins from the bed.
I have found that last to be true.
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Offline Wort-H.O.G.

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Re: Barley Gelatinization
« Reply #4 on: January 07, 2016, 03:15:26 PM »
Yes, there is that problem in getting the starch out of the grain kernel. However, you can't boil the base malt before mashing since that would denature the enzymes needed for starch conversion. Exposing more of the kernel surface area via finer milling is one way to improve extraction. An additional consideration is that the mashing process should extract more of the starch if the mashing temperature is eventually brought to a fairly high temp such as 168F as part of a mash out step.

Jeff, while I agree that pH can play a part in tannin extraction, I still believe that its the high wort gravity and the osmotic stress it places on the remaining husk and kernel matter that helps limit tannin extraction during decoction. We can keep pH low throughout sparging, but if you let the final wort gravity get too low, you will extract tannins from the bed.

whats too low?
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Offline jeeyeop

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Re: Barley Gelatinization
« Reply #5 on: January 07, 2016, 05:36:28 PM »
thanks for the great responses as always!

if i'm understanding correctly, boiling would actually bring out more starches from the kernels which would make them more readily converted, but no one goes that route because the enzymes necessary would be denatured?

for a follow-up question then: if you were to boil grains without those enzymes (rice, corn. etc) then cool them down to 150 and then add amylase containing grains, would you get a better starch conversion from those boiled grains than you would have gotten then just by reaching their gelatinization temperatures?

Offline mabrungard

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Re: Barley Gelatinization
« Reply #6 on: January 07, 2016, 05:51:10 PM »
Ken,

I've found that I need to keep the gravity of the final runnings above 3 brix to avoid the tannin perception in my beers. The more popular recommendation is to stay above 2 brix, but that didn't cut it for me.
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Re: Barley Gelatinization
« Reply #7 on: January 07, 2016, 06:15:10 PM »
thanks for the great responses as always!

if i'm understanding correctly, boiling would actually bring out more starches from the kernels which would make them more readily converted, but no one goes that route because the enzymes necessary would be denatured?

for a follow-up question then: if you were to boil grains without those enzymes (rice, corn. etc) then cool them down to 150 and then add amylase containing grains, would you get a better starch conversion from those boiled grains than you would have gotten then just by reaching their gelatinization temperatures?

You see a small improvement, a couple of gravity points at the most. The decoction is a double mash, in that you have the main mash and the decoction boil  going at the same time. The enzymes are denatured in the thick part, but he majority of the enzymes stay behind in the thin main mash, and then will convert starches when the two are recombined.

In this second part you are describing what is called a cereal mash, which is then recombined with the main mash. This might help.
https://www.homebrewersassociation.org/attachments/0000/1298/SOzym00-Pilsner.pdf
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Offline Wort-H.O.G.

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Re: Barley Gelatinization
« Reply #8 on: January 07, 2016, 07:40:19 PM »

Ken,

I've found that I need to keep the gravity of the final runnings above 3 brix to avoid the tannin perception in my beers. The more popular recommendation is to stay above 2 brix, but that didn't cut it for me.

Thanks Martin. I haven't had any issues but was curious.


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Ken- Chagrin Falls, OH
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Offline brewinhard

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Re: Barley Gelatinization
« Reply #9 on: January 11, 2016, 07:09:45 PM »
Ken,

I've found that I need to keep the gravity of the final runnings above 3 brix to avoid the tannin perception in my beers. The more popular recommendation is to stay above 2 brix, but that didn't cut it for me.

This is what led me to quit fly-sparging and adopting a no-sparge process for wort production.

Offline HoosierBrew

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Re: Barley Gelatinization
« Reply #10 on: January 11, 2016, 07:24:22 PM »
This is what led me to quit fly-sparging and adopting a no-sparge process for wort production.


Same for me. Granted I wasn't as good a brewer then as I am today, but I pulled more tannins than I liked as a fly sparger. Really happy with batch sparging.
Jon H.