Explain decoction like I'm 5

[jklett]

I'll preface this by saying that I've been focusing on brewing traditional Bavarian beers lately thinking that if I can perfect my methods with them, then all of my other brews will be better because of it. I'm trying to understand decoction mashing and while I think I am getting the gist of it, it's not quite clicking for me. I'm trying to get a better understanding of what's going on other than scoop out some mash and boil it before adding it back. Like do I try to hold a temp to get some specific extraction before boiling and if so, doesn't boiling prevent later conversions from happening? I guess I'm not as much looking for a how but a why and what happens. Any advice on even resources(websites, books, articles,
etc...) would be helpful. Thanks in advance!

 

[IslandLizard]

If you own a copy of John Palmer's How to Brew, he gives a good explanation of the process. There are many others when using some web searches.

The critical part is that only a relatively part small of the mash (the thick grainy portion, of about a 3rd of the total mash), is being boiled. Most of the liquid (containing most of the enzymes) stays behind in the mash tun.

 

[bkboiler]

@Bramling Cross
I bet Barney the Brewer could answer this very well! : )

 

[GoeHaarden]

Have you read this?

 

[jklett]

If you own a copy of John Palmer's How to Brew, he gives a good explanation of the process. There are many others when using some web searches.

The critical part is that only a relatively part small of the mash (the thick grainy portion, of about a 3rd of the total mash), is being boiled. Most of the liquid (containing most of the enzymes) stays behind in the mash tun.

I'll have to pick up that book, I see it referenced a lot here.

So you're saying it's more akin to cooking oatmeal than boiling soup then? That's kind of where I'm not quite getting it.

Have you read this?

Thanks for the link, I'll check it out.



Thanks again for the replies, I appreciate the help figuring this out.

 

[Birrofilo]

Decoction would have the effect of having the starch "burst" completely (rather than have some which remains in the grains) and thus increasing efficiency. Also, the boiling would create melanoidins which will impart a twist on the flavour.

Czech beer PGI "České pivo" is all produced with the decoction method, which is compulsory for this PGI. By drinking different beers with the label PGI České pivo and Pilsner lagers without it one should theoretically be able to spot the different character. I can't, but I certainly like Czech beer, regardless of decoction.

Yes the decoction part is like cooking risotto or porridge, and it is labour-intensive as you have to stir this sticky mass.

 

[cactusgarrett]

Like do I try to hold a temp to get some specific extraction before boiling and if so, doesn't boiling prevent later conversions from happening?

Some history, whether you like it or not: decoction was originally the process used "back in the day" (hence, with undermodified malts). Without thermometers, mash temps couldn't be monitored, so old-timers would just brew by feel: decoct in order to hit the next sacc rest steps. With the advent of thermometers and well-modified malts, people argue that the process doesn't actually contribute flavors (enough to be noticed) and that it's unnecessary. I'll leave that up to you to decide. Personally, I believe it does contribute something that melanoidin or other caramel malts don't lend, regardless of the process (contrary to many people thinking) not actually going thru the Maillard reaction - which needs to occur at 280F+.

Process: you're basically pulling a "thick" decoction: nearly all grains, minimal liquid. Some people, on their way up to boil, hold the grain at various rest temps (145F and 160F, look up Hochkurz schedule) to mimic further mashing, but this (in my opinion) is just a waste of time since nearly all your enzymes are still in liquid you left behind in the mash tun and continue to work there. Boiling (as mentioned previously) just releases more starches by grain kernel destruction, and thus usually bumps your extraction efficiency a bit.

 

[bkboiler]

Also cool to think about (and super relevant) is because thermometers were not invented...some breweries would locate their operations on an acquifer that had a reliable ground water temperature year round.
Then they would draw perhaps 80% of the strike volume and boil and mix that with the remaining 20% of strike volume at groundwater temp to achieve a perhaps 180F strike temp (a long time ago well insulated was synonymous with HIGH thermal mass...not foamlike materials that we have today with low thermal mass AND low conductivity).
The mash tun often was a somewhat insulated vessel that may not have been capable of being direct fired. Thus, the decoctions were a way to add heat to the mash (either for temp stability or to progress to higher temperatures).
This is relevant for folks who like to mash in coolers (more power to you!).

 

[Twinkeelfool]

How doing decoctions make your porters,IPA’s or stouts better?

 

[monkeymath]

How doing decoctions make your porters,IPA’s or stouts better?

Landbrauerei Schönram makes a pretty magnificent Imperial Stout. Guess how they make it...

(In no way am I saying the decoction was necessary, or even beneficial, to make a good Imperial Stout. Just that there are people much better than any of us at brewing, in this case Eric Toft, that seem to deem it beneficial.)

 

[oakbarn]

Like a 5 year old? Don't touch that. Its HOT!

 

[Barbarossa]

Still waiting for that over simplified explanation...

 

[oakbarn]

Still waiting for that over simplified explanation...

It just doesn't matter if you do it. Let me tell you a story:

In olden days, we had to plant the wheat and harvest it. We then had to grind it to make flour. We then made bread which we had to let rise into a big puffy ball. We don't have to do that anymore, we can go an buy bread that is ready to bake if we want fresh bread.

It is sort of the same with trying this. It is no longer necessary to do all those steps unless you were able to get unmodified grain. The modified grain makes those steps a waste of time. Don't bother me again and do as I say.

 

[duffy5018]

My input:
Don't use your good kettle for it. It leaves a scorched mess in the bottom, no matter how much you stir, and is a b!tch to clean. Plus, I, personally, don't think it does a whole lot you can't do with a dash of melanoidin. But if you've never done it and are interested, do it. It's an... experience.

 

[bkboiler]

Mr Barley has lots of energy. In fact he's bouncing off the walls. And daddy is going to help Mr Barley clean his room. So we've got to keep Mr. Barley focused on the tasks he's got to do.
So when Mr. Barley picks up the toys first, we're going to celebrate that listening by giving him some more energy, like maybe a hot cocoa.
Then when Mr Barley gets back to cleaning we're so happy for him, that after his next task is complete he's getting a cookie. Then after Mr Barley's cleaning is all done, he's exhausted, and we are going to not give him any more energy. In fact, he needs to rest.

 

[Barbarossa]

Oh well. Here's a nice video about it.

 

[Shermwormbrew]

Start mash at a lower temp like 122F take a 3rd of grains from mash with little liquid, boil wet grains while stirring a lot. Move back hot grains to main mash to then increase main mash temp. Do it once or up to 3 times. Just need to pick what resting temps you want your main mash to sit at in between decoction.

 

[cactusgarrett]

Start mash at a lower temp like 122F

Not all the time. I've done mashes where I utilize just one rest temp then decoct to hit mashout, as well as a beta and alpha rest while using the decoction to either hit alpha and/or mashout temps. If you want to include a decoction, there are surprisingly a number of ways to do it.

 

[Shermwormbrew]

@cactusgarrett
Agreed, he said explain like he’s 5 so why tell him there’s a ton of ways without giving him somewhere to start! Also why I said you need to pick where you want your main mash to sit in between decoctions. But all in all the important part is to just always be brewing and making beer! Cheers!!!