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Question on Rest times with decoctions

This came up this weekend when we were brewing our weizenbock. We doughed in for a beta-glucan rest at 105* (target temp). We only wanted to have this rest for 5-10 minutes, then decoct to our sacc rest (154)

So with the 1/2 bbl system, we pulled off about 9 gallons of the mash and brought it to a boil. This of course took some time. So on the remainder of the mash, it was sitting at a beta glucan rest for probably close to a half hour as we removed the decoction, brought it to a boil, and boiled it.

So I guess in reality, we did a half hour beta glucan rest. How are you supposed to only do it for a few minutes? I suppose you could infuse additional liquor or recirc to a higher temp?

Sub question: any ill-effects from a half hour beta glucan rest?

Why the beta-glucan rest? Did you use unmalted wheat?

I don’t see the extended rest being a problem. Its just breaking down gums. I’d do it by step mash rather than decoction. And according to Palmer its only necessary for unmalted grains. And truth be told when I use unmalted wheat (witbier) or rye (rye IPA) I don’t do this rest, it still runs off fine just a little slow. I think you may get more body anyway.

No it was malted wheat (~55%), but when I did my roggenbier with 60% malted rye, running off was a gargantuan PITA, and did it as a BIAB! It was just a big concrete gooey mess, and given what I’ve heard about the dangers of protein rests, I thought a beta-glucan rest would break down some of the…well…glucans and make lautering easier (we did this beer on the 1/2 bbl system). Since its a weizenbock, we didn’t want to break down too many of the proteins with a protein rest.

We wanted to decoct the beer for melanoidin/maillard character (which is probably way more easily achievable by just adding/upping melanoidin/munich malt), but us brewers just love tinkering around with stuff.

It was actually pretty cool. Once we reached our beta glucan temp, the mash liquid had this weird milky color. Then we pulled it off and decocted, and it got to this awesome chestnut brown color.

I used to do decoctions all the time. Will never do them again - had my fill.

They do get you great malt flavor and fantastic efficiency, but you can get there by other means in so much less time.

As far as times go, whatever times you go by, it refers to the decoction portion - so the bulk is sitting there at the original temp much longer.

My two stages would tend to go:

  1. Somewhere around 50 C (off hand I completely forget). Sit for 20’. Decoct 1/3 - bring to sac rest temp (hold 20’) - bring to boil and hold 20’. Whole decoction would take at least 1 hour.

  2. Add back to achieve sac rest temp for the bulk. Hold 20’. Decoct 1/3, slowly bring to a boil and hold 10-20’. Add back to achieve mashout temp.

Eventually I started simplifying my process until I decided to single step immersion everything with better results and less time spent.

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