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Old 01-09-2013, 03:15 PM   #1
Oct 2009
Ottawa, Ontario, Canada
Posts: 5,505
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I've got to admit, I'm curious about decoction mashes. As I understand it, it's the only way to achieve the kind of rich, malty perfection of a beer like an Ayinger Celebrator. So far, I've only ever done single infusion batch sparge mashes.

But the idea of a decoction mash intimidates me.

I've watched a few YouTube videos on decoction mashes, and the part that I don't get is how you boil some of the grains without burning them. The videos I've watched seem to take both liquid and grains in the decoctions, but what consistency? Is it the same as the main mash? More liquid than grains? More grains than liquid? And why don't the grains scorch onto the bottom of the kettle used for boiling the decoction, creating a messy cleanup and releasing a flood of harsh tannins?

Is anyone else intimidated - yet still intrigued - at the thought of a decoction mash?

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Old 01-09-2013, 03:20 PM   #2
Nov 2012
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sign me up... intimidated and intrigued

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Old 01-09-2013, 03:21 PM   #3
Apr 2009
Omaha, Ne
Posts: 209
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i've only done single infusion mashes so far, but am going to tackle a decotion this next beer. from what ive gathered, is when you boil the decotion you want the same ratio as your main mash. and to keep from burning you grain you want to stir it a lot. please someone correct me if i am wrong.

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Old 01-09-2013, 03:22 PM   #4
Oct 2012
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I wouldn't say I'm intimidated, but never really cared to try. Don't they say that for today's well-modified malts you don't really need to do decoction ?

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Old 01-09-2013, 03:25 PM   #5
Jan 2011
Toronto, Ontario
Posts: 704
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Usually you pull "thick" (mostly grains) for the first few steps, and then "thin" (more liquidy) for the final decoction. If you stir constantly, you won't have any burning, think of it like cooking oatmeal, and don't crank the heat too high. It's not intimidating, it just adds a whole lot of extra time to the brewing process.

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Old 01-09-2013, 03:33 PM   #6
Feb 2011
Phoenix, AZ
Posts: 214
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I was intimidated by a decoction mash until i tried it. They are not really hard but are alot of work. Yhe reason you dont want alot of liquid is that is where all the enzymes are located to cinvert your mash and if you boil the liquid you will kill them. So to get around this you pull the tick part or the grains. There is still liquid in the grains though and it will come out as you heat it up. So the key to not burning (which is a very real concern btw) is low heat and stiring. You should have a temp increase of around 2-3 degrees per min, no more. So doing the math, going from 130 to boiling should about 40 min (212-130=82 degree rise divide by 2 degrees per min). And you should be stiring it throught that time. So they are alot of work but imho i thing they are worth it you get some flavors that are just not possible to replicate exactly with differnt malts. Btw, when/if you do a decocotionnfor mashout (152ish to 168) you can pull a thin mash and get more liquid because the converstion is complete so it can be rqised quicker. Hope this helps!

Typing on a tablet sucks.....

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Old 01-09-2013, 03:46 PM   #7
Sep 2012
Posts: 924
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Not sure if I understand the point in a decoction mash. First, by pulling out liquid and boiling it, you're destroying the enzymes. which kind of is contrary to the whole purpose of malting and mashin. Second, at a time it was used, people didn't have nearly the understanding of malts nor the consistency of modern malts. The modern malting process itself does much of the work a decoction mash was intended to do with the ****ty malts of the past.

I'm all for doing things because they're cool. It's a different way of doing things, it's traditional, etc. I'm not crapping on that aspect of it. I just don't see the purpose of it from a technical point. People will say there's a difference in flavor, but how much of that is placebo, and how much of that is interbatch variations? Probably more than due to the decoction.

Am I missing something here? If I'm mashing to take advantage of the enzymes, why embark on a process like decoction that intentionally destroys the enzymes?

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Old 01-09-2013, 03:55 PM   #8
Jan 2011
Toronto, Ontario
Posts: 704
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Typically you pull your decoction, do a 15 minute Sacch rest and then boil it, so the enzymes have done their work already, and there's still a lot more enzymes in the main part of the mash. This supposedly helps develop more melanoidins due to the Maillard reactions that take place during the boiling of the decoction.

I believe it's also from the time before thermometers, so by removing and boiling a certain volume, when you add it back to the mash, you raise the temperature through the desired rest temps for conversion. It's a pretty cool technique when you think about it, it also allowed mashing to take place in unfired mash tuns.

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Old 01-09-2013, 04:26 PM   #9
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Nov 2011
Santa Rosa, CA
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I took an advanced brewing class at the LHBS and here's how we did a single decoction:

EQUIP: 3-tier direct fired system, 15 gallon vessels
RECIPE: Maibock, 10 gallons
20# German Pils
2# Vienna
1# German Wheat
1# Belgian Aromatic
1# Honey Malt
4 oz Acidulated Malt - only used in the 60% grist portion

Split the grist 60/40 into 2 vessels.
60% of the grist is brought to 120F and held there. While this is resting bring the remaining 40% to 158F and hold for 10 min, then raise the temp to boiling and boil for 10 minutes.

By now the first 60% has been resting for about 40 min due to the ramp up and boiling time of the 40%.

Combine the 40% with the 60% which should bring the entire grist to 150-158. Rest here for 90 minutes. We then heated to 165-170 for a 10 min mash off. We then fly sparged.
Something is always fermenting....
"It's Bahl Hornin'"

Kegged: Bourbon Barrel Imperial Stout
On Deck: German Lager

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Old 01-09-2013, 10:00 PM   #10
Oct 2012
Woodinville, WA
Posts: 861
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A great, great thread guys; all the major points on the subject seem to have been covered by someone.

Combining rjsnau's post with BigRob's gives a great understanding of the subject.

It IS kind of scary the first time you do it, and I was definitely afraid of scorching, enzyme destruction, and extracting tannins but worried for nothing.

How much of the mash you pull out, how thick it is, whether you rest at saccrification temps on the way to boiling and how long you boil are actually all variables; the answer is "it depends" what you're trying to do, what ingredients you used as an input, and what style beer you're trying to make.

As others have pointed out you're almost always pulling a fairly thick decocation (use a strainer) and you're definitely stirring when the mash gets close to boiling and through the boiling. The longer you boil each decoction the more color and malliard flavor development that you get so generally darker colored beers (bock) have the decoctions boiled for longer periods of time and ligher beers (Pils, Marzen, Hefe) for shorter periods of time.

Any time that you're pulling a decoction that hasnt' sat through at least a 45 minute sacc rest you need to do the sacc rest on the way to boiling to convert those sugars. -Do it around 68C -70C and you'll get faster conversion. This lets this part of the mash get converted; you're also generally ok on the enzymes as the enzymes have leached out of the grains and are actually in the liquid portion at this point (this is another reason that the decocted portion should be thick - you'll boil and kill fewer enzymes). -This is also why it's not a big deal to decoct a more liquidy decotion to get to mash out temps (conversion is already completed) -you also don't want to boil a lot of grain this late in the process because you might extract a bit more unconverted starch from the grain at this point and then kill the enzymes and add the starch back to a mash that has dead enzymes (mashout quickly dispatches them). On the enzymatic side we're also talking about a german technique that used german malts that are generally pretty high in enzymatic power so the degradion of enzymes isn't a big deal. If you're using pale malt instead of lager malt and tons of speciality malt as in a modern American intepretation of a German beer you COULD run into problems. (I could see an American dunkel bock recipe that utilizes pale as a base malt running into issues with a decoction.)

The traditional profiles are there for a reason and are associated with certain styles of beer for those same reasons.
As far as whether such a profile is necessary; certainly not to get melanoidins and not because modern malt is undermodified but there are some very highly experienced brewers and judges who swear that there is a difference between decoctions and infusions with additions of speciality malts high in melanoidins. (Although there are plenty of experienced brewers and judges who claim the opposite so try it for yourself and come to your own conclusions.)


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