Decoction technique?

[cweston]

I've mostly brewed styles of British, American, and Belgian origin, but I'm interested in exploring more German brews: particularly Marzen, Alts, and Munich dunkels.

Am I right that the basic decoction technique is to draw off a bit of mash form the tun, mostly liquid, boil it, and return it to the tun in order to step the temperature up for the next rest?

So a typical decoction schedule might include a protein rest, a saccrification rest, and a mash-out, using a decoction to achieve each step up?

Am I on the right track?

 

[Desert_Sky]

good question. I still do a single infusion for each brew. Im thinking if I start doing a protein rest, I may get rid of my chill haze. So Im going to keep an eye on this thread.

 

[cweston]

good question. I still do a single infusion for each brew. Im thinking if I start doing a protein rest, I may get rid of my chill haze. So Im going to keep an eye on this thread.

I hope I'm not insulting your intelligence--but you can do multiple rests without decoction: you start with a thick mash and just add the sufficient amount of boiling water to bring the mash up to the right temp for the next rest.

 

[mysterio]

I'm no decoction expert but I did read a fair bit about it before my Oktoberfest. Basically you've got it right. Usually it's about a third of the mash that's drawn off (beersmith etc will calculate this for you), raised to sacc temp then boiled for ~10mins before being returned to the mash, in order to raise the temperature. Hopefully, this will help with the clarity and release extra melanoidins for maltiness.

I would recommend leaving the protein rest unless you're deliberately sourcing under modified pilsner malt, or using a large percentage of wheat. Nearly all modern malts have low nitrogen levels and it's just not necessary, nor will it provide any benefit. I recommend searching the forum for the thread 'the case for protein rests' for some insight. If you're suffering from chill haze I'd try whirfloc or extra irish moss before a protein rest.

A more suitable decoction schedule would be a maltose rest (beta rest) around 60C, then decoct to an alpha rest around 70C. Then you can mash out and sparge as usual. A thick decoction for mash-out is not recommended as you might release extra starch that won't be converted.

For further reading you might want to try Noonan's 'New Brewing Lager Beer'. Not got it myself but I've heard that's the book to read on the subject.

Edit: Here's the protein rest thread : https://www.homebrewtalk.com/showthread.php?t=7547

 

[Desert_Sky]

I hope I'm not insulting your intelligence--but you can do multiple rests without decoction: you start with a thick mash and just add the sufficient amount of boiling water to bring the mash up to the right temp for the next rest.

insulting my intelligence? naw.....

pointing out my laziness? yea maybe :cross:

 

[AdIn]

...
Am I right that the basic decoction technique is to draw off a bit of mash form the tun, mostly liquid, boil it, and return it to the tun in order to step the temperature up for the next rest?
...

You need to draw thick part of mash, i.e. grains. But if you do second decoction for mush -out - then you draw thin part. This is because you don't want to introduce more starches in to your mush when most of enzymes are alredy stopped activity.

 

[Beer Snob]

Am I right that the basic decoction technique is to draw off a bit of mash form the tun, mostly liquid, boil it, and return it to the tun in order to step the temperature up for the next rest?

Am I on the right track?

No, its the think part of the mash that you want to draw off of. Very little liquid. This is brought to ta temperature slowly then boiled for a certain length of time (per recipe). This process breaks down the enzyms I believe. It's thick so you obviously are going to be stiring it constantly to keep it from burning. I've been doing resarch on this too cause I want to brew a wheat. This method keeps comming up.

 

[G. Cretin]

My last wheat beer I tried to do decoctions on
My scedule was 20min acid,protien,beta,alpha, mashout
all "lifts" as I would call it were 40% of the whole boil for twenty min held at temps for 40 min each.
I wasn't impressed but I'm sure it was me and a lack of skill.

 

[Brewsmith]

I got some good info from Baron von BeeGee on decoction.
https://www.homebrewtalk.com/showthread.php?t=9875
I went with the double decoction for my hefeweizen. Now that I have done it, I porbably could have done less of a protein rest because the head retention is not so good, but the beer tastes great. I also didn't pull out enough for the thick mash. I pulled a couple quarts, grain and all and boiled it, but adding it back didn't raise the temp enough. I ended up adding some boiling water to get the infusion temp closer. At mash out is did another decoction, and tried to get mostly liquid, but some grain was in there. In all it was fairly easy, just more time consuming. The resulting beer tastes great, though. I think I'll do it on all of my HW's from now on.

 

[Lost]

Use a colander to pull out the thickest 1/3 of the mash. Heat to saccarification temp and hold for 20 minutes.. then boil for a good bit and add back to the mash. Be sure to watch the ph - keep it at 5.2 so you don't leach any tanins from the grains when boiling.

I've found that how much the temp in the mash is raised is hard to predict. If the mash is cool then adding the boiled 1/3 has a substantial impact on the temp but as the mash gets hotter then the effect of the decoction is less - this has been my experience at least.

I've done it three times now and am not getting any better at hitting the temp rests I'm shooting for. It's a pain, a mess, and it makes the brew day substantially longer. It's also mighty easy to burn the decoction if you don't stand there and stir it constantly for the whole time you're cooking it and especially when you're boiling it. It may make the the beer a little better but for me it wasn't worth it. That's why I'm currently working on a steam setup for my next batch..