Beta Glucan rest?

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SpanishCastleAle

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I'm making an Oatmeal Stout tomorrow. I read somewhere that if using a decent amount of Oats that a Beta Glucan rest at 110o F might be a good idea. Easy enough...but what is it doing and/or why do it? Are we just breaking up the chain of glucose molecules? Is the purpose to ensure the wort is not too viscous?

For an Oatmeal Stout, would you do a protien rest too? Being a Stout it's not like clarity is a big issue. And what temp (or temps) for saccarification do you like? I was just gonna do the Beta Glucan rest then shoot straight up to 154o-156o F or so.

It it matters this is a 6 gal batch with:
8# Maris Otter
1# Roast Barley
1# Crystal 60L
1# Flaked Oats
.25# Molasses
 

remilard

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The point* is to break up beta glucans which make the mash "gummy". Most soluble fiber supplements (eg psyllium husk) are mostly beta glucans so if you have ever partaken in Metamucil you have an understanding of the textural qualities. So this will give you a more liquid mash that is easier to lauter.

Barley and oats both have a lot of beta glucans although the malted versions will have experienced some breakdown during malting. That is why you are worried about your raw oats more than your malted barley.

Now, if you want to do a protein rest as well I know that Fix used a beta glucanase rest at 40 C and he said that he noticed no advantage to doing it if he was also going to use a protein rest at 50 C. So if you want to do a protein rest, I would say skip the glucanase rest if you want.

* Breaking down beta glucans will also contribute to a clearer wort. George Fix believed that there were other advantages to this rest. He experienced better efficiency which he did not attribute entirely to improved lautering. He also noticed that conversion happened 3x faster during sacchrification if he used this rest and he believed that indicated a preperation of enzymatic activity that would generally be a good thing.

Since I know where this thread is going to head let me say now that the beta glucanase rest has nothing to do with the modification of the malt and in fact Fix only used it for well modified malt (using a protein rest instead for undermodified malt).
 

FireBrewer

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^^^^^^^^ good explanation. :mug:

1 pound of flaked oats is not a lot. You can do a beta glucan rest if you want. You can do a protein rest if you want. You can even combine 'em and do a rest at 122° for 20-30 mins. But they're not absolutely necessary.
 

remilard

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Yeah, most home brewers would do a single infusion mash there and really most of the beta glucans in that mash are still from the barley so if you aren't doing that rest normally, I see no reason to change and do it here.
 
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SpanishCastleAle

SpanishCastleAle

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Thanks for the responses...good explanation remilard.

You can even combine 'em and do a rest at 122° for 20-30 mins.
The higher I can do this rest the better. Getting to ~155oF from ~110o F will take pretty much the max amount of infusion water I'd like to add without adding heat. Adding heat is not a problem...I mash in a pot...but I usually still try to do it with infusions.

I tried doing protien rests (@ 122o F) just for better clarity and I did notice that conversion takes place quickly. I did an acid rest (@ 95o F) on the Bohemian Pils in my sig...but I had no pH strips then (I do now)...but it converted really quickly too.
 

pjj2ba

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I'm becoming a big fan of protein rests. My rig easily allows it and I think it has been adding a lot of body to my beers, more so than simply mashing higher.
 

GilaMinumBeer

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Very recently I obtained 9 of the Classic styles series. I have oredered the other 7.

The most notable thing I have read from each of the book is that ALL of the authors suggest a 122*F protein rest regardless of the mash style.

I too plan to try my hand at adding this rest to my schedule and hope that I too reap the benifit of faster conversion. easier lautering, and improved wort clarity.
 
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SpanishCastleAle

SpanishCastleAle

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pjj2ba,
Looking at my notes; when I stopped brewing years ago almost every mash I did had a protein rest. Usually step-infusion but occasionally decoction. I just remember that my beers came out better when I did step-infusions/decoctions than when I didn't so I almost always did them (even when it didn't appear 'necessary' or appropriate). And I don't recall having any head retention problems from it. I didn't really know why but I knew it usually made my beer better and that was enough for me.
 

remilard

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George Fix used infusion to go from 40-60 and then I think direct heat to go to 70.

He added all of the specialty grain and maybe some of the base grain when he did the step infusion once he reached the second rest. He said that the grain addition acted as a "brake" on the mash temperature and also obviously this helps you to maintain a reasonable mash thickness at both rests.
 

quantumbeer

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I don't do beta-glucan rest for wheat beers or all-barley beers. For oat beers, well I would do a protein rest for 45 minutes. I have thought of beta-glucan rest as something to do for rye beers.

My beta-glucan rest is like this, be sure to use rice hulls:
15 minutes at 122F. This first part is a small protein rest to loosen the protein matrix.
1 hour at 104 (use chopped ice to drop the temperature)
15 minutes at 122

then 140 - 158 to convert the starch.
 
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