Help me figure out how to do a decoction mash for my bock

[drunkinThailand]

So my next batch will be a bock, and it calls for a decoction mash. I have read up, and while I see that decoction is not necessary these days, based on what I've heard about it adding flavor I'd like to try it.

So my basic understanding of how that would work with BIAB is to start out with all the grains in my pot, bring to the first temp, take out some of the grains, heat/boil/etc in a seperate smaller pot, then add it back into the mash. Does this sound right?

If so, can you help me figure out how much grains to take out and what temperatures to use? The recipe I found here is not to clear to my untrained eye. Here it is as I have found it:

Protein Rest Add 28.50 qt of water at 126.6 F 122.0 F 35 min
Saccharification Decoct 12.08 qt of mash and boil it 155.0 F 45 min
Mash Out Heat to 168.0 F over 10 min 168.0 F 10 min

So I bring the whole mash to 122F for 35 min, then take out 12 qt of mash (mostly grains) and boil it or bring it to 155F for 45 min (please help clarify this)? Then add it back and mash out the whole deal?

thanks a lot for any help

 

[GilSwillBasementBrews]

Bring it to the boil and add back which should drive your temp to the 155F

 

[drunkinThailand]

I've been reading up and I think I understand it a bit better now, but now what I am wondering about is this: if I remove a third of the grains and boil it won't I destroy the enzymes in those grains and lose a lot of fermentable sugars?

 

[doug293cz]

I've been reading up and I think I understand it a bit better now, but now what I am wondering about is this: if I remove a third of the grains and boil it won't I destroy the enzymes in those grains and lose a lot of fermentable sugars?

You will denature the enzymes in the decocted portion of the mash. Most of the enzymes are in the wort after the first few minutes of the mash, so taking a thick decoction minimizes the fraction of the enzymes that are affected. Most mashes have way more enzymes than needed for complete conversion (excess diastatic power.) If you were planning a decoction with lots of enzyme free adjuncts, or low diastatic power malts, then maybe you would have to worry about insufficient diastatic power, which could result in incomplete conversion.

Brew on

 

[drunkinThailand]

I have been thinking about this a lot, and the easiest/most hassle free way to get the flavor benefit of decoction and I'd love some feedback about this idea...

Start my mash normally, wait fifteen minutes so most of the enzymes are in the wort, then pull out a third of the grains to boil for 30 minutes. I figure after that it should be about time for mash out, so add the boiling grains back into the mash to reach mash out temp.

then proceed to the boil as normal. does this sound like a good plan? or is it a bad idea for some reason i have missed.

thanks again for any and all input

 

[Cyclman]

I think that is a plan. Or, you could use 5% melanoidin malt, which mimics a decoction well from a number of tests.