Originally Posted by Lost
Kai, yes the temp is more of a range in a step mash but I still worry that I'll miss the range entirely. I'm just not quite sure what effect adding a third of the boiling hot mash back into the tun will have - knowing exactly how much it will raise the temp at a given temp is probably a product of experience which is something I don't have yet. Since you've done it (and sucessfully I presume) you know what to expect and know if its easier or harder than an infusion mash. Frankly though, I expect that it will be harder or else we'd all be starting with decoction mashes. Now, for a pro it does offer more control and, probably, more consistency but as you can tell I'm no pro. Heck, I'm happy with the control AG affords me over the extract brewing methods.. that was definitely a big step up!
I use Beersmith to calculate the volume of the decoctions and always add 1 to 2 qts to compensate for evaporation and other factors. It's always easier to cool it down with ice than heating it up with boiling water. And for boiling water you will need another pot.
So far, it wasn't that hard to hit in the temp range. But I miss by 1 to 2 C (2..4F) most of the time and have to correct.
One interesting fact about decoctions is, that they were invented when thermometers weren't available yet. By boiling a predetermined amount of the mash and mixing it back in, brewers were now able to repeat the temperatures of their mash rests more reliably. But now that we have good thermometers, this is not why decoction mashes are still done.