Decoction Question

Australia & New Zealand Homebrewing Forum

Help Support Australia & New Zealand Homebrewing Forum:

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


Well-Known Member
Reaction score
Have been looking at doing a decoction brew and just have a quickie.

When boiling the grains, what keeps the elusive tannins from coming out of the husks? Is it the lack of water? the ph?


I'm not an authority on this, but from what I have read, the first boils of the grains do not leach out the tannins, but the last decoration boil should be free of grain.

Here is a link to some better info than I could provide. Hopefully some of the members who know more on this will respond.
Why bother is my question. If you are using any of the Local or Imported malts availible they do not benefit from decoctions.

Thin beer and poor head retention is a result of decocting fully converted malt.

If you are looking to increase malt profile in a beer then use up to 30% Carapils, Carahell or similar.
40% for low alcohol for flavour/profile/head, 5% for head retention etc.

like anything the Carapils or lower crystals can be used in a number of ways.

Decoction can be tempting so we should not discourage... no matter the result. 1/3 the thick stuff (if you can get to it - not sure how) is a way to go. The pH of the mash stops the tannin extraction - raised pH's during sparge and tannins go hand in hand. On the HB level tannins should not be an issue. chemistry of sorts kicks in the '000's of litres.
Decoction not necessary, how many times have I heard this mantra?

Decoctions certainly needed for wheat beers, FAN and all that.

Other beers? Decoctions improve extract (more gravity from same amount grain) and increase maltiness, melanoidins and bready/grainy flavors.

Yes, decoctions lengthen the brewday, so what?

And, yes, a mash tends to end up with a pH inthe low 5s, avoiding the dreaded tannins

Jovial Monk
Jovial_Monk said:
Decoctions certainly needed for wheat beers, FAN and all that.
Why is that, JM? I thought wheat beers benefited from less amino acid content and free amino nitrogen, as their presence causes the yeast to later mop up some of the characteristic wheat beer flavours it produces.
///, why bother you ask? I'm looking at brewing a few weizens in the next few weeks and from what I gather, decoction really helps.
I'm looking at turning out a wheat beer this weekend, very tempted to give a decoration mash a go
I have made dozens of decoction beers over a 2 year period. With todays well modified malt it is not required. As suggested before use some melonoiden or carahell.
If you want to do a decoction only try a single, skip the acid rest as this will make your beer too thin (tust me).
Mash at 64C for 60 minutes then take out 40% and bring it to the boil. Boil for 10 - 15 minutes and slowly return back to the mash. This will raise your mash temp tp 70C and hold this for 20 minutes. Sparge at 77C.
If your mash efficency is around 65% like mine a decoction will raise that to about 72% so you will need to adjust your recipe with this in mind.
It will increase the colour of your beer and add another hour to your mash day.
BTW I only do single infusion mashes now as the results are the same.
Ray, that looks like the way to go for a first decoration, thanks. One question when you take out from the mash for the decoration boil do you try to only get the liquid and leave the grain, as per the advice I have read for this higher temp step?
When taking out the grain for a decoction make most of it grain with some wort as I do no like to have it too dry. Just make sure you have some wort covering your remaining grains in your mash tun.
When it starts to boil you will notice all this white foam being created, have your wooden spoon with you and keep stiring as you do not want any burnt grains, so you need to stir while it gets to the boil and stir while its boiling. Great to watch it change colour in the boil.
Hope this helps
Ray_Mills said:
If your mash efficency is around 65% like mine a decoction will raise that to about 72% so you will need to adjust your
Another 65% man.
I feel better now I know I am not alone.
I haven't decocted a beer for a long time now (years maybe).
Just remember, stir, stir, stir. Doesn't take much to burn a thick decoction
Is an immersion heater an option or that just silly, use the stove?
I used Rays method for an Oktoberfest I brewed back on the Queens B'day weekend.
The resulting beer was outstanding, with a lovely malty flavour. It lasted 4 weeks in the keg :chug: .

Fromt he German Wheat Beer book:

"Decoction mashing. . .maximise breakdown of proteins. . .[and]. . .highest possible degree of starch breakdown as well. . . .if the grist contains no more than 50% wheatmalt, a step infusion mash is possible. . . . double decoction is well suited to brewing a Dunkles or Weisenbock. . . .[developing] full-bodied character. . .increase the amino acid concentration of their worts as darker malts typically yield less amino [acids] . . . .also helps to deepen the color and intensify the malty, breadlike aroma and flavor. . ."

A decoction could be pulled to mash out: merely heat the decoction to boiling and boil for 10 minutes, does not lengthen the brewday very much.

Jovial Monk
Jovial_Monk said:
A decoction could be pulled to mash out: merely heat the decoction to boiling and boil for 10 minutes, does not lengthen the brewday very much.

Jovial Monk

Part of what the decoction does is burst the starch granules to allow better action by the enzymes. Wouldn't it be a bit late at mash out to do this?

Iam with pedro there, i have done a tripple decoction and after reading NBLB part on dection over and over again i saw now reason to actually decoct to mash out.
For mash out its a simply matter of just infusing up to the temp.
generally the decoctions will be before the sac rest. In a tripple decoction i had two sac rest one at 60c for 30mins and one at 70c for 30 mins.
All up i mashed in at 40c decocted up to 50 then to 60 then to 70c and just infused up to 78c, for mash out, As far as i know this is the most common techniquie for a tripple decoction mash.
So if your only doing one decoction i would mash in at 50c then decoct up to 65-70c for the results your are after in a real decoction.
Like ray said early it does change colour dramatically and when you return the decocted part you see it is much darker than the main mash, Even so iam not sure how much clolour this actually adds to the finished beer as i have read some stuff that says there is not much colour increase in the final beer but i have also read some stuff that says there is a colour increase, so hey iam not too sure here.
The reason i did it was simply for the fun of doing it at least once and to say yeap i have done a decoction and pulled of a great beer with it, i still can't really say how much of a improvement over a standard mash it was but it was fun and didn't take that much longer.

In mine the 40c and 50c rest i didn't have any probs, the final beer had a perfect dense head with great retention.

Anyway if your giving it a crack software is the easiest way to work out how much volume you need to take out each time, i took just enough wort to cover the grains and added pure water if it did get to thick during the boil, i stood there stirring it the whole time which you'll have to do.

Have fun decoctors.
Cheers Jayse :chug: