OK, I have long been planning to do my first decoction mash. I have done a fair bit of reading on the subject (wish I had Papazian's book...) and I have a few questions. First off the mash profile in Beersmith is very confusing.
Decoction Mash, Triple, Lager Step Time Name Description Step Temp
15 min Dough-In Add 9.39 L of water at 21.1 C 21.1 C
20 min Acid Rest Add 6.52 L of water at 74.2 C 40.6 C
10 min Protein Rest Decoct 3.05 L of mash and boil it 50.0 C
20 min Dextrinization Rest Decoct 7.03 L of mash and boil it 68.3 C
5 min Mash Out Decoct 5.04 L of mash and boil it 76.7 C
Mash Notes: Derived from Noonan, "New Brewing Lager Beer". A pure infusion/decoction mash with no temperature steps. The book recommends adding boiling water for the second step, though it appears it would come in too high in temperature.
The first two decoctions are from the "heaviest" part of mash while the third is from the "thinnest".
He also recommends you hold Dextrinization until it passes an iodine test (probably more than 20 minutes)
The 15 minute dough in I understand, that is to hydrate the grist before it is taken for decoction. Then after 15 minutes of hydrating the grain I add 6.52L of 74.2C water to hit the Acid Rest temp, and this is where I get fuzzy. It says to rest at this temp for 20 minutes, have I already taken the grist and begun the boil? Do I wait until the end of this rest and then decoct and boil for 10 minutes as it seems to suggest? Also these rests and boil times seem to be a bit far fetched in being possible, not to mention going against everything I have read which suggests boiling the grist for a minimum of 30-45 minutes. Beersmith even contradicts itself by telling me to do a 20 minute Dextrinization Rest, then going on to tell me that Noonan recommends holding it until and iodine test passes and that it is "probably more than 20 minutes"?
Further I wonder how you skim "protein scum" from the top of a boil that has no standing water? I have not done it, so the answer to that may be obvious, but in my head if the boiling mash is so thick that there is no free water how will it get a layer of scum at the top of it? I plan to do the boiling in a 13L stockpot on a three ring burner. Would the three ring be too hot and scorch the grain? Maybe if I just use the two inner rings?
I realise this is a very long post but I appreciate anyone taking the time to clear this up for me!