Decoction Method

When doing a decoction mash are you supposed to boil some of the grain with the wort to raise the temp of the mash? I have been reading about decoction mashes and I am very confused. Can someone please explain how to perform a decoction mash? Thanks.

You've got it right. You scoop out some of the mash, grain and all, and heat it (usually to a boil). You then add it back into the mash to reach your desired temperature.

I let Beersmith do the calculations for me as to how much to take out and what temp to bring it to. It's actually kind of fun and adds a new wrinkle to the brewing process.

For all but a mashout decoction, you scoop out a thick portion of your mash from the bottom of the tun, bring that slowly up to whatever rest temperature you are trying to achieve (for a mini-rest to take advantage of the enzymes that are in there), and then bring it up slowly to a boil for anywhere from 5-20 minutes. The boiling time depends on what you want to acheive, but I tend to go between 5-10 minutes. It's a slow process, but the only way to get certain character in your beer.

There's more information in the Wiki, or you can check out Noonan's "New Brewing Lager Beer." That's a great resource.


TL

TexLaw said:

There's more information in the Wiki, or you can check out Noonan's "New Brewing Lager Beer." That's a great resource.


TL

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I was reading Noonan's New Brewing Lager Beer last night. That is what caused the confusion because I was under the impression that you should never boil the mash. Now it all makes sense as he said to "add the hot liquor back into the Mash tun". What is this Wiki thing?

+1 To TexLaw.

I do single decoctions fairly frequently and follow Noonan's advice. Mash-in to low 130's (for highly modified malts, which most are), wait 5 minutes, pull decoction (thickest part of mash), bring decoction to next rest temp (mid 150s), hold decoction at that temp for 10 minutes, heat decoction to boiling, boil decoction for 5 minutes, return decoction to mash... bringing mash temp to mid 150s, hold mash at that temp for 20 minutes.

Since I have a direct-fired system, I heat up the whole mash to mash-out temps. I don't think you get much maltiness from mash-out decoctions (thinner), so I don't think they're worth it unless you don't have a direct-fired mash-tun.

One tip that worked for me I read in BYO magazine was to take the thin mash out leaving the thick portion behind to boil (to me much easier than trying to remove the thick portion from the bottom to boil) I did this with my last 10 gallon batch and it worked out real well. I put the thin portion into a cooler to hold the temp and then added back after the 20 min decoction boil I used direct fire recirculating mash tun in conjuntion to a single decoction mash.
Mashed in at 122 pulled the thin mash and stored in a cooler. direct fired 1/3 of total thick mash to 150 held for 20 min. then boiled for 20 mins while stirring. After boil added thin mash back, blended temp was 135 rested 10 mins. Ddirect fired to raise whole mash temp to 154, rested for an hour then raised temp to 168 for mash out.

Watch Kaiser's decoction mash videos and I think most of your questions will be answered.

greggor said:

One tip that worked for me I read in BYO magazine was to take the thin mash out leaving the thick portion behind to boil (to me much easier than trying to remove the thick portion from the bottom to boil)

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This work very well for the enhanced double decoction that I have been pushing as a replacement for triple decoctions when working with modern malts. It’s important that you either add the mash held in the cooler very quickly back into the kettle that holds the decoction or put the decoction into the mash held in the cooler. If you add the mash from the cooler into the decoction in small steps, you will denature most of the valuable enzymes in that cold mash as you are decreasing the temp down from boiling. But you need to go the other way around which is slowly increasing the mash temp by adding the hot decoction.

Not an issue if you add the cold mash all at once but that doesn’t allow you to slowly approach your target rest temp. Which may also be a don’t care if you can heat the mash tun. But will be a problem if you overshoot the rest temp by having to little cold mash.

Brad, thanks for posting that link.

Kai

At the end of http://https://www.homebrewtalk.com/f36/issues-decocting-76205/ is my "Readers Digest" decoction post.

Kaiser, that was an awesome video. That really helped me understand what I was reading. Why is it OK to boil the grain for a decoction but raising the mash temp to high for an infusion will draw out nasty tasting tannins?

My first AG batch is in the primary. It was a single infusion mash. I made an equivalent PM batch so that I can compare the flavor. I would like to try a decoction mash with the same recipe to compare the difference in flavor between a decoction and infusion mash. The beer that I brewed is an American style Pale Ale. It is 70% Pale Ale malt and 30% Light Munich malt.

Thanks to all for the information.

Yeah, that video is the only reason I even attempted a decoction. My advise though, take 1.5-2 times what beersmith tells you...I've come up short on my temps each time I've gone by what it calculates. Then again, maybe my technique still sucks.

Bob8690 said:

Kaiser, that was an awesome video. That really helped me understand what I was reading. Why is it OK to boil the grain for a decoction but raising the mash temp to high for an infusion will draw out nasty tasting tannins?

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Thanks.

You can boil the decoction and not the whole mash b/c you need to keep some enzymes to convert the starches liberated by the boil. And in addition to that I read of mash schedules where the mash is boiled and lautered at near boiling times but a water extract of the cold mash (which contains enzymes) is added to the run-off in the kettle that has been cooled to convert it before the hop boil is started. Excessive tannin extraction was not mentioned as the problem but the additional time that was needed after running off completely eliminated the time gained from the quicker lauter at higher temperatures.

I think that pH is more important in extracting tannins than temperature and that the reason for the 170F sparge temp limit comes from commercial brewing where the brewer is interested in preventing complete denaturation of the a-amylase as it is needed to convert starches that are liberated during the lauter.

Kai

I have never done a decoction mash.
I have often thought that using a large s.s. bowl to hold the mash to be decocted, placed in a pressure cooker and held at plus 212 degrees would be a convenient, no scourch technique.
Maybe slight scourching will help some styles though.
Goofy idea?
rick
w. mi