Author Topic: Mash rests, their functions, and when to use them.  (Read 3467 times)

Big Monk

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Re: Mash rests, their functions, and when to use them.
« Reply #30 on: July 17, 2017, 11:26:03 PM »
OK, you believe it.  Any evidence you can offer?

Well, I haven't done laboratory-quality experiments, but here's specific numerical data from my last 10 batches so you can review it and decide for yourself if you think I'm full of crap:



Yes, these were all single infusions.  Temperatures are averaged over the course of the mash, typically starting about 3-4 degrees higher and falling 3-4 degrees lower than the numbers reported.

Cheers.

76% with 3787? Did you do that on purpose?! 😉

Offline erockrph

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Re: Mash rests, their functions, and when to use them.
« Reply #31 on: July 18, 2017, 01:33:27 AM »
Just to touch on a few points that were brought up.

A) Greg Doss's presentation is exactly why I started targeting 153 on my single infusions

B) I'm with Dave in thinking that Beta hangs around long enough up to the mid 150's to do what it needs to do. It's not like you flip a switch and it all denatures at once. There is a rate of denaturation (and an associated half-life). Given the enzyme content of most modern malt, even if the half-life of beta amylase is relatively short at these temperatures, there is likely enough enzyme present to do what it needs to do. Plus, the increased alpha activity at these temps will help make beta more effective.

C) While I still single-infuse for most of my ales, I have been doing a simple 2-step mash (147 x 60 minutes to 162 for 30 minutes) for my light lagers, and I like the results. I also have had good results doing an iterated mash for my barleywines (mash half grain at alpha temps, pull grain and add remainder to drop down to beta temps). This has resulted in great attenuation in some huge beers (my best was 84% in an 1.142 all-MO BW).
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Offline JT

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Re: Mash rests, their functions, and when to use them.
« Reply #32 on: July 18, 2017, 01:41:44 AM »
OK, you believe it.  Any evidence you can offer?

Well, I haven't done laboratory-quality experiments, but here's specific numerical data from my last 10 batches so you can review it and decide for yourself if you think I'm full of crap:



Yes, these were all single infusions.  Temperatures are averaged over the course of the mash, typically starting about 3-4 degrees higher and falling 3-4 degrees lower than the numbers reported.

Cheers.

76% with 3787? Did you do that on purpose?! 😉
I've not used the yeast, but that seems within normal range? 


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Offline dmtaylor

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Re: Mash rests, their functions, and when to use them.
« Reply #33 on: July 18, 2017, 02:59:59 AM »
76% with 3787? Did you do that on purpose?! 😉

No, I'm not quite sure what happened with that one.  It was my first time with that strain and it was super sluggish for some reason even fermenting at room temp.  It turned out okay but not awesome.

Wait.... Yeah, that is pretty normal for this strain, no?  Maybe you were thinking of 3711?
« Last Edit: July 18, 2017, 03:09:19 AM by dmtaylor »
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Big Monk

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Re: Mash rests, their functions, and when to use them.
« Reply #34 on: July 18, 2017, 11:29:42 AM »
76% with 3787? Did you do that on purpose?! 😉

No, I'm not quite sure what happened with that one.  It was my first time with that strain and it was super sluggish for some reason even fermenting at room temp.  It turned out okay but not awesome.

Wait.... Yeah, that is pretty normal for this strain, no?  Maybe you were thinking of 3711?

Well it's normal for all malt wort. I assumed you were making a bet with some sugar.

I use 1214 and 3787 for my own Trappist inspired Ales so I'm using at least 12% sugar. I get 86-88% AA with either of those stains.

Big Monk

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Re: Mash rests, their functions, and when to use them.
« Reply #35 on: July 18, 2017, 12:47:51 PM »
One of the interesting things that Bryan has turned me on to in the recent months is tracking the percentage of extract you get after each rest. We use an adapted form of Kai's first wort gravity chart in our spreadsheets and we have shown that for 100% conversion we nail that gravity consistently.

What does that mean? Well we know that we can expect 100% of the available first wort extract at the end of our mash. Since we are using no-sparge, that turns out to be our pre-boil gravity. In order to track extract across the mash, you simply take gravity readings with your refractometer after each rest. What you'll see is the progression of available extract for a certain temperature and time.

For instance, we both use sight glasses so we can SEE conversion happening and gravity readings confirm this. If you know that you expect 12.9 Brix at the end of the mash and you read 5.2 Brix at the end of the 144 F rest, you know that you have obtained 42.6% of the first wort extract from that rest. You could certainly infer that beta amylase was very active at that temperature. If you then show 8.5 Brix after your 147 F rest, you know that 23.3% additional extract has been gained, and so on and so forth. Bryan has been hitting ~90-95% of his pre-boil gravity after his 3rd beta rest.

You can also use this as a troubleshooting tool for poor conversion or even high gelatinization temps for new malts. If you run a multi beta amylase rest schedule and your first rest is 147 F with a step to 153 F, and you don't see any extract content until the ramp to 153 F, you know that your gelatinization temperature lies somewhere on that spectrum. If you see sluggish gains in extract content throughout the mash, you may have poor conversion.

For those using single infusion, this troubleshooting tool could also be used to determine whether you should extend rest times. For instance, if you plan on mashing for 45 minutes, but at the end of the duration you only have 65% of the deisred extract, you can extend the rest time and take another reading at 60 minutes, 90 minutes etc. and use that as a metric for that temperature rest.



Offline The Beerery

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Re: Mash rests, their functions, and when to use them.
« Reply #36 on: July 18, 2017, 03:08:06 PM »
Aye!
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Offline chumley

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Re: Mash rests, their functions, and when to use them.
« Reply #37 on: July 18, 2017, 03:55:07 PM »
I admit that I screw around with multiple steps, but when it is all said and done, you can't beat the old Listermann mash regime of 150°F for 90 minutes.

Offline erockrph

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Re: Mash rests, their functions, and when to use them.
« Reply #38 on: July 18, 2017, 05:01:49 PM »
One of the interesting things that Bryan has turned me on to in the recent months is tracking the percentage of extract you get after each rest. We use an adapted form of Kai's first wort gravity chart in our spreadsheets and we have shown that for 100% conversion we nail that gravity consistently.

What does that mean? Well we know that we can expect 100% of the available first wort extract at the end of our mash. Since we are using no-sparge, that turns out to be our pre-boil gravity. In order to track extract across the mash, you simply take gravity readings with your refractometer after each rest. What you'll see is the progression of available extract for a certain temperature and time.

For instance, we both use sight glasses so we can SEE conversion happening and gravity readings confirm this. If you know that you expect 12.9 Brix at the end of the mash and you read 5.2 Brix at the end of the 144 F rest, you know that you have obtained 42.6% of the first wort extract from that rest. You could certainly infer that beta amylase was very active at that temperature. If you then show 8.5 Brix after your 147 F rest, you know that 23.3% additional extract has been gained, and so on and so forth. Bryan has been hitting ~90-95% of his pre-boil gravity after his 3rd beta rest.

You can also use this as a troubleshooting tool for poor conversion or even high gelatinization temps for new malts. If you run a multi beta amylase rest schedule and your first rest is 147 F with a step to 153 F, and you don't see any extract content until the ramp to 153 F, you know that your gelatinization temperature lies somewhere on that spectrum. If you see sluggish gains in extract content throughout the mash, you may have poor conversion.

For those using single infusion, this troubleshooting tool could also be used to determine whether you should extend rest times. For instance, if you plan on mashing for 45 minutes, but at the end of the duration you only have 65% of the deisred extract, you can extend the rest time and take another reading at 60 minutes, 90 minutes etc. and use that as a metric for that temperature rest.
Good info, thanks for sharing!

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Offline Pricelessbrewing

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Re: Mash rests, their functions, and when to use them.
« Reply #39 on: July 18, 2017, 05:20:23 PM »
One of the interesting things that Bryan has turned me on to in the recent months is tracking the percentage of extract you get after each rest. We use an adapted form of Kai's first wort gravity chart in our spreadsheets and we have shown that for 100% conversion we nail that gravity consistently.

What does that mean? Well we know that we can expect 100% of the available first wort extract at the end of our mash. Since we are using no-sparge, that turns out to be our pre-boil gravity. In order to track extract across the mash, you simply take gravity readings with your refractometer after each rest. What you'll see is the progression of available extract for a certain temperature and time.

This is exactly what I did as well when I wanted to test my conversion rate (conversion efficiency vs time).

Big Monk

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Re: Mash rests, their functions, and when to use them.
« Reply #40 on: July 18, 2017, 06:03:38 PM »
One of the interesting things that Bryan has turned me on to in the recent months is tracking the percentage of extract you get after each rest. We use an adapted form of Kai's first wort gravity chart in our spreadsheets and we have shown that for 100% conversion we nail that gravity consistently.

What does that mean? Well we know that we can expect 100% of the available first wort extract at the end of our mash. Since we are using no-sparge, that turns out to be our pre-boil gravity. In order to track extract across the mash, you simply take gravity readings with your refractometer after each rest. What you'll see is the progression of available extract for a certain temperature and time.

This is exactly what I did as well when I wanted to test my conversion rate (conversion efficiency vs time).

It's an extremely simple and very elegant way of determining if you have issues.

Offline curtdogg

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Re: Mash rests, their functions, and when to use them.
« Reply #41 on: July 22, 2017, 12:13:34 AM »
Does any of this help determine  FG?

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Big Monk

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Re: Mash rests, their functions, and when to use them.
« Reply #42 on: July 22, 2017, 03:03:28 AM »
Does any of this help determine  FG?

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Well, the fermentability of the wort is set by the β rests in particular so yes it does. Although the only way to accurately determine final gravity is a FFT. I do one for every batch.

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Re: Mash rests, their functions, and when to use them.
« Reply #43 on: July 22, 2017, 04:31:36 PM »
I spent the day yesterday with a German guy trained in brewing in Germany.  He said he thinks that at least 90% of the time there's no need for mash steps.  Found that interesting.
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Offline BrewBama

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Re: Mash rests, their functions, and when to use them.
« Reply #44 on: July 22, 2017, 06:20:49 PM »
I spent the day yesterday with a German guy trained in brewing in Germany.  He said he thinks that at least 90% of the time there's no need for mash steps.  Found that interesting.


 That is interesting.  I wonder why they do it if not required. Seems that would waste resources which Germans are violently against.


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