Decoction

[zgardener]

So, I just learned about decoction mashing, and I was wondering if anyone could enlighten me on what kinds of beers that this method would be good for. I typically just go with a basic single mash with a batch sparge, and am looking into a RIMS, but I'm wanting to try decoction mashing on some future batches.

Can this be used on just about any style? Or should it be reserved for lagers or certain ales that I want clear and malty?

 

[michael.berta]

Traditionally German lagers and German wheat beers are the way to go. When I did a decoction my mash efficiency went up to 85+ percent so you may want to build a higher mash efficiency into your recipe. The few times I did a decoction I ended up with an overly fermentable wort and might have had less malt character due to lower final gravity..

There is a lot of debate as to whether a decoction mash will make a beer any better. I won't rehash the arguments because they have been made over and over again. But just don't think that a decoction mash is the missing link to making that perfect beer. There are other ways to make a beer more malty.

 

[Yooper]

I've done decoction on Maibocks and Vienna lagers, and I believe a mash-out decoction on an alt. That's about it for me. I enjoy the process, and I like the results.

 

[PinkyOFloyd]

I have a recipe that calls for a double decoction mash. The process itself doesn't seem to be all that complicated but it seems to defy basic brewing logic. By that I mean, it's instilled in our brewing brains to not allow the temp of the mash to exceed 170F or it will extract tannins, yet with a decoction mash we're to remove off ~1/3 of the mash grains & wort and slowly bring it to a boil. What am I missing?

 

[Yooper]

Well, it's true that when you're steeping or sparging or mashing, you don't want to exceed 170 degrees. That is partially because you don't want to denature the enzymes, but it's also because you risk tannin extraction from the grain husks.

In a decoction, you will bring a portion of the thick mash to a boil. That seems to defy the rules, but it doesn't. Tannin extraction is not just a function of temperature, but also of pH. When you do a decoction, you pull a very thick sample. That allows you to boil that sample, gaining maillard reactions, without allowing much tannin extraction because of the lower pH of the decoction mash.

 

[z987k]

Well, it's true that when you're steeping or sparging or mashing, you don't want to exceed 170 degrees. That is partially because you don't want to denature the enzymes, but it's also because you risk tannin extraction from the grain husks.

In a decoction, you will bring a portion of the thick mash to a boil. That seems to defy the rules, but it doesn't. Tannin extraction is not just a function of temperature, but also of pH. When you do a decoction, you pull a very thick sample. That allows you to boil that sample, gaining maillard reactions, without allowing much tannin extraction because of the lower pH of the decoction mash.

I think the reason for this, is that tannin extract has so much more to do with pH than temperature. Tannin extraction in sparging is almost always from oversparging - not overheating.
If you head over to Kaiser's site, he's got a section on pH and tannin extracting and the solubility of tannin's gets much higher with high pH than the temperature increase. I think he says a mash pH of 6.0 is around the threshold.

As to the OP, most all continental lagers are appropriate, as well as alts. I've done one with a belgian wit that was around 70% unmalted wheat. I've done it with an Strong Scotch as well.

Here's a good article on the subject: http://www.strandbrewers.org/techinfo/decoct1.htm

If you want to make a lambic or wit really true to style, it's worth reading up on turbid mashing as well... it's kind of like the opposite of decoction.
http://www.byo.com/stories/techniques/article/indices/45-mashing/1743-turbid-mashing