Did my second try at decotion for a hefeweissen beer today. Went much better than the first, since I actually did some research on how to do it properly. The first time, I kept pulling out the wort and boiling that, and didn’t pull enough to hit the temps I wanted, and had to boil more and did like 6 steps. And I used torrified wheat, not wheat malt, and got a very low OG, totally missed my intended OG by .030… But now I know to actually pull out the grains from the mash. Did everything right, hit all my temps right on, (only did a single decoction to raise the final step to 158*) and am amazed at how simple it really was. Many thanks to everyone on these forums for good advice and spot on info. Cheers!
Once you do a decoction, you go, that wasn’t too hard.
Sort of like making your first homebrew. It is more work, but you are making beer so it may not seem like work.
Made 2 friends that wanted to learn all grain brewing do a triple decoction with me. After we were done, I said “Now you can do this much more easily.”
Congrats! I’m still working on how to properly do a decoction…I can boil the heck out of the pull but always seem to be a few degrees short of the goal temp. It can be done though!!!
I don’t do it for step-mashing. I mash at my regular temp. Do a decoction and add it back to the tun. Then do a mash-out but these days I even forego that sometimes.
I had this issue at first as well. I found its much better to pull more than what you think. You can always reserve some of the decoction and let it cool off before adding it back to the main mash if adding all of it will put you over temp. Its much less of a PITA than being under your temp and scrambling to get it up.
Pull more than you think you need, or minimally have some boiling water on standby to get the temp up in a pinch if need be. But reserving some of the decoction and letting it cool before adding it back has no ill effects.
I think this often happens because brewers pull the amount of mash for the decoction that a calculation tells them they’ll need to add back at boiling temperature to raise the main mash to the next step. That doesn’t account for boil-off during the decoction process. I pull an extra 10-15% to account for boil-off. This can also be addressed by adding back some brewing water from the HLT to make up for the boil-off - especially after a longer decoction boil.
Once you’ve done it a few times with similar recipes and volumes, you can pretty much “eyeball” how much you need to pull. The key is to have enough decoction at boiling temperature to bring sufficient heat back to the main mash to hit the next step. If you have more than you need, you can leave it behind in the decoction kettle for a bit to cool back down to the main mash temperature before returning it to the MLT.
agreed. I generally pull as much thick mash as I can. I get a big fine mesh kitchen strainer and get the bulk of the grain out. Like mentioned, if I have too much, I set it aside, cool it down a bit closer to mash temp and then add it back. Youve boiled all of the enzymes and such out of there anyways, so as long as you get it back in before you sparge you’re good to go.
I did my first decoction last night. I doughed in with 152F water and it stabilized at 144F, which was close to what I wanted (145F). Let that sit for 25 minutes, then pulled (what I thought was enough) thick mash, something like 5 qts for a 7lb grain bill. Boiled for 20 minutes, stirring constantly and added it back. Well, the main mash temp had dropped too low, down to about 136 or so. So adding the boiling decoction back only brought the temp back up to about what I had mashed for 25 minutes at. Damn it! I think there was too much head space in my mash tun (10 gallon cooler for 7lb grain bill). Ended up draining off about a gallon of the thin mash, brought to boil, then added it back. That brought the temp up to 158F like I had wanted. Let that sit for 45 minutes. Then sparged as normal.
I kind of wonder if mashing thin would make it more difficult to bring it up to the next rest, also. I think I mashed with 13qts for 7lbs, so like 1.7qt/lb or something like that. Perhaps I’ll mash thicker next time. By the way, this was a 4 gallon batch.
Anyone have any tips or insight on this experience? This was for a schwarzbier, just wanted to try a single decoction.
Thanks.
I always pull 25% more decoction than any calculator thinks I’ll need. I also keep a pot of water near boiling to use if even 25% more isn’t enough to hit my target. I mash really thin, like 3-4+L / kg, so I don’t think that’s necessarily the issue.
I used to have trouble with decoction temps as well, especially when I was using an igloo cooler and boiling seperately. I used to lose temp pretty quick after i pulled the grain out. Always had to have boiling water ready to go…
These days on my direct fire system, my main mash keeps temp like a champ. That way when I add it back, I dont have to compensate for any main mash temp loss.
1 quart thick mash for every pound of grain is the way to go. I first heard of this from Michael Dawson on BrewingTV (which he learned from Northern Brewer’s Chris Farley) and more recently I read the same formula in Classic Beer Styles Series: Bock by Darryl Richman (EXCELLENT book btw). It has always been my method and works so well, I can’t see a reason to change.
A little boiling water is always good to have around because you lose a little water to boil-off during the decoction. You can pull a little more grain off if you want to compensate for potentially hitting a low temp, but I find when I pull 1 quart of grist per pound of grain, almost all the grain has been pulled already and it really isnt worth fishing out the tiny bit left. Kill two birds with one stone - add water 
I did a single decoction on the O-fest I made last weekend. As usual I missed the next step temp by 5 or 6 degrees but 1.5 qt. of boiling water put me back on track. I figure that if I know I’m going to need some boiling water I can be ready.
isn’t the ROT to pull 1 qt of thick mash per lb or grain? so you would want to pull 7 qt thick mash for the decoction in that case.
I tried a decoction with little success but I was not really prepared. I did not have a good way to get only the thickest portion of the mash out. I will try again soon and use my spider to pull the thick portion, should get pretty much only grain that way. Is that TOO thick?
I like to mash really thin with my decoction mashes, starting around 2qt/lb. This is a little more traditional with German brewing. I do this because it feels a little more comfortable and seems like I get a nice buffer since many of the mash’s enzymes will be in suspension in that liquid part after I draw off a thicker part for the pulls.
I also like to make my pulls thin enough so that they can boil without needing constant direct stirring. You’re not trying to caramelize the grain when you’re boiling a decoction. You just want to rupture the grain and concentrate the flavors.
Something to keep in mind is that on professional systems that utilize decoction (like in the big factory brewery in Aying, Germany), they are moving around the grist with pumps. If you’re making a decoction pull so thick that it looks like it couldn’t be pumped through hoses/etc, it is probably too thick; you’re making more work for yourself and greatly increasing the risk of scorching the mash which usually ruins the beer (depending on the style).
Also, I always pull more than my software (Promash) tells me I need. Then I add it back to the main mash in a staggered manner. Then if I am below my step temperature, I just add a little more; if I am above, I just keep the rest in the decoction pot until it cools enough to add back to the mash.
This is true. It didn’t help that I’d lost a bunch of heat because of the headspace in my mashtun. I plan to try it again on a dunkel in the next week or so with my 5 gallon cooler and have some near boiling water at the ready.
I think you want a little liquid in the decoction, but not too much. Obviously you don’t want it to be just grains, otherwise, there’d be nothing to boil.
I do around 1 decoction per month and have always used 1 quart grist per pound of grain. Using a water to grist ratio of around 1.5-1.75q/lb is a good for me.
The thing you want to try to do is leave as much water behind in the main mash when pulling your decoctions. This leaves all of your enzymes in the main mash, which is what you want. Also the grain holds alot of the water and as you decoct it, the liquid absorbed by the grain will be released. So what appears to be pretty dry at first will end up being alot more oatmeal-y and watery at the end of the decoction.
Thanks for the insight, Michael. Cheers.