Decotion Mash

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

The Professor

Well-Known Member
Nov 30, 2004
Reaction score
West Jordan, UT
Has anyone ever tried a decoction mash? I did recently and the rich malty flavor of the beer was quite nice. I was a little worried about boiling the mash solids for 20 minutes due to the fear of leaching tannins from the grains, but the finished beer had no adverse astringency. All you do is remove 1/3 of the mash solids leaving the liquid in the mash tun. Then boil the removed mash solids for 20 minutes stirring constantly so as not to scorch the mash. Then mix the boiled mash back into your mash tun with the rest of your grist and the temperature will rise about 10-15 degrees depending on the starting temperature and the volume of your mash. This is how step mashing was accomplished in the old days before fancy homebrewing equipment such as a thermometer. This can be done up to 3 times (tripple decoction mash) before you sparge. Just do not go over 168 degrees for your mash total temperature and have some knowlege of the relationship of mash temp to sugar conversion with fermentables and dextrins (non fermentables) before attempting a tripple decoction. I would reccoment trying a single decoction after your grains have fully converted to sugar for the first attempt. You won't be dissapointed.
Sounds good but a little complicated (for me).

I've brewed about 6 times in the last three months, all extracts by John Bull and True Brew. Mostly porters, stouts and IPA's.

It's just so easy.

What you've described looks good, though.

For the Irish Stout I have fermenting now, I put in some oats at the last part of the boil for some extra smoothness.

I'll bottle it in a couple of days.

I have a porter ready in three or four more days.

I just like the 10-day ferment/10-day bottle and you're done.
Yeah it is a bit of a comittment. I will be brewing a monster of a porter tomorrow with a tripple decotion and it will likely take from 9:00 AM until 6 or 7 at night to be finished. But for me I love the whole process so it is rewarding work. Especially when you get to drink the beer. But in all honesty the best beer I ever made was an imperial stout from extract with grains.

Keep brewing the good beer Sara and take the process to what ever level remains fun for you. After all- It's all about the beer.
I've only done decoction with German beers...never Porter. Sounds fun! :)

As to extract/all-grain, I have yet to be convinced that you can make as good beer with extract as grain. And it costs as much as buying beer if you use extract.

I can always tell extract brews. They're almost always sweet. There seems to be something in the extraction process that carmelizes sugars and makes more unfermentable sweetness.

Now, I haven't made an extract batch in probably 15 years, so maybe extracts have gotten better, but a single-infusion all-grain batch, once you have the equipment, is a piece of cake, cheaper ingredients, and, in my opinion, better quality. You do have to have the space for equipment, though, and I wouldn't bother with 5 gallon batches for all-grain.

Also, I just enjoy the process of going from grain to beer. But, hey, to each his own. Just keep on brewing! :D

I like decoctions so much, that I never use step mashes anymore. The malt flavor you get, plus the greater extract potential, makes it more than worth the time. I'll use a 2 decoction for hefes, etc., and a 3 decoction for czech pils, munich dunkles, etc. There is a great deal of control in this proccess, but it does require a bit of planning. It also helps to have alot of btu's in the stove, or it will take forever. With a good propane burner, it's not so big a deal.
Also, it's been my experience that one doesn't need to boil the decoctions for more than 15-20 minutes. My reading has also confirmed this as well.

Latest posts