Nice thanks Gavin!
So the portion you grab out, you will always bring to a boil? Guess that makes more sense. I should probably just go read a book about it or something. But it's so much easier to ask questions on here. How do you handle water chemistry with a decoction? I know gavin usually does full-volume. I'm a BIAB batch sparger myself. So I normally try to aim for about 1.65 qts/lb, and then adjust to get my sparge within 4 liters of my water available from mash (advice from the batch sparge thread). Now I'm treating both my mash and my sparge water with my mineral additions. Unless I'm mashing pretty high, I don't really need to acidify my sparge water, but I do add a bit of acid malt into paler grists. Would I still be just mashing the same volume as usual about, and treating it the same, simply taking enough out and bringing it to a boil in order to raise the temp? How many steps are typical with decoction. Sorry for all the questions. Is there a thread that I can read up on this instead of invading this one with the dumb questions?
I follow my normal mash chemistry protocol. I know that decoctions can push the pH down a bit, so I might aim a little higher than normal (5.4-5.5 room temp instead of 5.3-5.4).
But yes, basically mash like normal at your lowest step, and then remove however much you need (better to grab more than no enough).
Depends on what you're doing stepwise. If you only want a single decoction, do it to raise to mashout. Just pull it, heat it to boil, boil for maybe 15 minutes, and add back.
Worth noting just in case, decoctions need to be stirred constantly.
If you want to do decoctions at lower steps before full saccharization, then giving the decoction its own mini conversion rest is a good idea. So if I'm decocting from a protein rest at 128 to a 145 beta rest, I'd heat the decoction to maybe 152-154, let it sit for 20 minutes, and then boil it.
Multi step decoctions take a lot of planning and time and work. I don't brew lagers hardly ever (I've done one, I don't have a fridge and it's too difficult in a swamp cooler), so the only beers I do them on are my Weizens. My Kolsch and Alt get a single decoction that's it.
But for my Hefe-
I'll mash in at 110F. After maybe 20 minutes, I'll pull my first decoction, heat it to 152, hold it for 20 mins, boil it 5 mins, add back, bringing my whole mash to 130. I'll immediately pull a second decoction, again heat to 152 for 20 mins, boil it 5, add back, bringing it to 152. Let that sit 45 mins. Pull another decoction, heat it straight to boiling, boil it for 20 mins, add back bringing back to 168, hold 10 and sparge.
That way the main mash spends about an hour at 110, maybe 30 mins at 130 (but very little in the main mash, more than half ends up in the decoction), a little over an hour at 152, and then mashout. All intentionally timed. Mash takes just shy of 3 hours.
My Kolsch is simpler. 10 mins at 130, infusion to 150 for 60 mins, decoction boiled for 20 mins to mashout, and sparge. For Belgians I'll follow the same general schedule but instead of a single sacch rest I do 145 and 156-158, with how fermentable I want determining the time at each, and I'll skip the decoction and just do another infusion.
