For all you Decocters out there... when you boil your (thick) decoctions, how much liquid boil-off (gallons per hour) do you get? Is the rate comparable to your wort boil, or something less? TIA!
Less, as the pot has less area, and the flame is not too high to avoid scorching. Edit,you are at a boil for less,time also.
Yeah, I can't answer this. Thought never occurred to me. I'm a beersmith-**** and just let it do the work for me. But, I can tell this would be valuable to know.
I'd imagine there are a few variables at play - diameter of kettle, kettle material, elevation above sea level, probably others? Could always measure some set amount into your decoction pot and boil it for an hour or half an hour and then measure again.
If your biggest problem when doing a decoction is worrying about boil off rate then you've got it made, buddy. I'd think it depends on how thick you pull and pot size. I'd ballpark it at about half your regular boil rate and go from there. I doubt you'd notice more than a quart unless you plan on boiling for an extended period of time.
Because I'm going to do a thick decoction, which I have never done. And I'm picky about hitting my intended volumes and gravities. I know my mash efficiency will probably change with the decoction, but I'm trying to minimize the variables.
I remember watching on BrewTV that thick decoctions shouldn't actually affect your efficiency that much. The reasoning was that most of the enzymes are in the liquid portion of the mash. So as long as you pull thick and minimize the amount of liquid you take out of the mash tun you should be fine.
Decoction tends to increase efficiency a bit as the action of boiling the grain makes the starch granules more available for subsequent conversion. To answer the OP, I never experienced much boil off during decoction, certainly never enough to be concerned about. I probably spilled more mash on my garage floor during the process of transferring to and from mash tun and decoction kettle than I boiled off.
I agree with others that your water loss should be minimal, and within the range of error of the rest of your process. If you really want to know and have a good scale, you can weigh your decoction vessel pre- and post- boil. edit: It's not handy to me right now but I'd also refer you to Noonan's New Brewing Lager Beer, probably still the best writing in English on decoctions. I'd be surprised if he had nothing to say regarding your question.
