Sacc Rest following Beta Glucan Rest

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jabraben

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We grew some barley at the farm associated with the college where I work and after having it malted we found out it is quite high in beta glucans. The maltster recommended a beta glucan rest at 113F and I'm planning to do one for 20 minutes. For the beer I'm brewing, a robust porter, I'd normally do a single sacc rest at 152F for 60 minutes. Should I simply decrease that to 40 minutes for a total of 60 minutes make other changes to account for the fact that alpha amylase will have been working, albeit at a much slower rate, during the initial rest plus the sacc rest and avoid too thin a beer?
 

VikeMan

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It's actually the Beta amylase (more so than the alpha) that might be working a little bit during your beta glucan rest. But I wouldn't expect it to be doing much and I personally wouldn't shorten the Sacch rest.
 

Vale71

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Don't sweat it. At that temperature you will be well below both gelatinization temperature and optimal saccharification temperature, which means you'll basically get no conversion at all. You will have some effect from the ramping up from a lower temperature as this allows gelatinization to start sooner and will start activating enzymes but I wouldn't change anything in the schedule unless your first beer comes out with significantly higher attenuation.
 

Brooothru

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We grew some barley at the farm associated with the college where I work and after having it malted we found out it is quite high in beta glucans. The maltster recommended a beta glucan rest at 113F and I'm planning to do one for 20 minutes. For the beer I'm brewing, a robust porter, I'd normally do a single sacc rest at 152F for 60 minutes. Should I simply decrease that to 40 minutes for a total of 60 minutes make other changes to account for the fact that alpha amylase will have been working, albeit at a much slower rate, during the initial rest plus the sacc rest and avoid too thin a beer?
The answer is a little complicated, and my take on things is a little bit different. If you're planning to do a beta glucan rest at 113F you'll be well below the nominal temperature where beta amylase becomes active ~130°F. Beta amylase activity peaks around 146°F. That will also be below the range where Alpha amylase becomes active. Chances are that 113F beta glucan rest temperature will not result in gelatinization sufficient to allow beta and alpha amylase enzymes to convert the starches to saccharins. So, maybe.

Now, with all that said, 153F is the perfect compromise temperature for a single temp mash since it maximizes in between both enzymes' activity ranges. That of course presumes that sufficient time at a high enough temperature has allowed for adequate gelatinization of the grains.

So really what you're asking is whether 40 minutes is long enough for conversation to occur.

The answer again is, maybe. Generally if you mash in at say 153F, the temperature will ensure gelatinization and beta and alpha amylase conversion after 60 minutes. Some data suggest that (mostly) complete conversion happens in as little as 20 minutes. So if you rest at 113F for beta glucan and then rest for 40 minutes at 153F, it "might" work, even "likely " work.

But the real question is, why not just leave the mash at 153F for 60 minutes which would almost guarantee conversion of the starches. If the maltster recommended a beta glucan rest, it's probably a reasonably good idea, since he knows his grain better than me. But conversion is not going to occur at 113F.

Brooo Brother
 
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jabraben

jabraben

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In these posts by Chris Colby, he goes into step mashes and closes by saying that a beer step mashed is going to be drier than a beer mashed at 153 alone. He claims that alpha amylase is active, though to a much lesser degree than within its optimal temperature range, even at this low temperature.
Choosing a Mash Method (I: Single Infusion Mashes)
The Steps in a Step Mash (I)
The first part isn't necessarily true. It is the mix of rest temperature, time and how modified the malt is you're working with. I wouldn't stress on what Chris Colby said and do a glucan rest to help it break down a bit. Starch conversion doesn't really begin until 130F(or so), and that temperature is within the range of your protein rest. So as Saint Papazian once said, "Relax, don't worry, have a home brew".
 

VikeMan

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jabraben

jabraben

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I don't see where CC specifically mentions alpha amylase in that context.
Thanks for setting me straight. He mentions that in a later article in this series but you are correct, it isn't in this context. He says that in the context of beta amylase rests, which aren't as cool as beta-glucan rests. I think what I'll do is the 20 minute beta glucan rest, then a 40 minute sacc rest at 152, at which point I'll do an iodine test or two. I'll have to do the first rest quite dry, maybe as dry as .8 qts/lb but my memory is that can be done, though it requires lots of stirring. Anybody have thoughts on that ratio for a first rest?
 

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In these posts by Chris Colby, he goes into step mashes and closes by saying that a beer step mashed is going to be drier than a beer mashed at 153 alone. He claims that alpha amylase is active, though to a much lesser degree than within its optimal temperature range, even at this low temperature.
Choosing a Mash Method (I: Single Infusion Mashes)
The Steps in a Step Mash (I)
That's all true. It's also true that beta amylase is active well into the narrow range of alpha amylase optima. I do almost all step mashes. My preferred styles are German/European lagers and American lagers, and West Coast ales (Blondes, APAs and IPAs) on the slightly drier side.

Since the temperature rise from 130F to beta optimum is greater than the time to rise from beta optimum to alpha optimum, my beers come out drier, even if I have equal rests. BTW, I've stopped doing liquefaction and protein rests entirely and just dough-in at 50C and heat to my target beta temp of 62C. Seems to give good results.

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VikeMan

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I think what I'll do is the 20 minute beta glucan rest, then a 40 minute sacc rest at 152, at which point I'll do an iodine test or two.
Just be aware that an iodine test will tell you that all of the starches have been converted into things that are not starches. It won't tell you anything about their fermentability. IOW, A typical (say, 60 minutes) mash will show a negative iodine test long before 60 minutes. I know you're trying to avoid going too dry, but I suspect your plan might take you too far in the other direction.
 
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jabraben

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Good point about the iodine tests. I take it you're suggesting I should do the 152 sacc rest for a standard time because the beta glucan rest won't have done the critical work that gets done during a sacc rest so there's no reason to shorten it.
 

VikeMan

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Good point about the iodine tests. I take it you're suggesting I should do the 152 sacc rest for a standard time because the beta glucan rest won't have done the critical work that gets done during a sacc rest so there's no reason to shorten it.
In a word, yes. :)
 
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