Decoction/RIMS

[Graham.C]

Once again I need some advice from the more knowledgeable out there.

Can someone clarify for me why its superior to do a decoction mash for a bock over using a RIMS system to do a multi rest mash. I always thought boiling grain was a bad idea, but from what I can tell that's what you end up doing in a decoction. From what I can tell, it really helps with under-modified malts in breaking up the starches. Is that the tradeoff then? More starches broken up vs extracting tannins, or am I way off the mark. If that's the case, does it matter as much with well modified grains then? I love a really malty dopplebock and would love to bring that into my regular keg rotation, but thought I would ask you guys for your expertise/experience.

[akr71]

because Germans always think that their way is better...

I don't know how many commercial breweries still decoct, but that's how they raised temps back in the day. I think the big thing is the big malty flavors you get from a decoction. Here is a good article that gets into the science of it: http://braukaiser.com/wiki/index.php?ti ... on_Mashing" onclick="window.open(this.href);return false;

[RubberToe]

Yeah I don't think you'd get the melanoiden formation doing a step mash through rims.

[amartin]

I don't have my brewing books around, but I think the way it works is that because you haven't sparged yet, your pH is lower so you don't have to worry as much about tannins. It's great for undermodified malts, but unless you malted the grain yourself, it's modified well enough and you don't need to worry about it. You do get the maillard reactions from the decoctions that you wouldn't get from an infusion mash, but some people say that you can just add a little melanoidin malt instead. That's the reason you would want to use it for a doppelbock though, is for the flavour.

If you really want to try a decoction mash, I'd recommend just doing a single decoction, from the protein rest to the saccharification rest. Since you probably don't need the protein rest in the first place, I'd keep it on the high side, maybe around 130¨F or so, to favour the enzymes breaking your larger proteins into medium sized ones, rather than the medium sized ones into smaller ones. Otherwise your body may suffer.

[Graham.C]

Yeah I don't think you'd get the melanoiden formation doing a step mash through rims.

That's what I was wondering. The more I read, the more I realize this point is contentious. Anyone have an opinion if decoction is worth the effort over just using malts with high melanoiden levels (melanoiden, caramunich, etc). It sounds like a fun experiment I will likely try regardless but I just wanted to know others thoughts on the matter.

[amartin]

I do them for bocks, dunkels and weizens, but I don't know if it's really worth it. I've never tried making bocks and dunkels without decoctions, and I usually use it for weizens since I'm using a ferulic acid rest and need to raise the temperature anyway.

Try it anyway, you'll grow as a brewer.

[Tim Gregory]

The first time I tried to do a full-on multi-step decoction mash and it was a disaster. I lost too much heat in my mash ton during the decoction boil and my next step temp by a wide margin. Ever since then if I'm doing a beer that is supposed to have it I just decoct some after the conversion rest, boil it, and then add it back for a mash-out.

If I ever try a full one again I'll mash in a kettle. That way if my temps are too low after adding the decoction back I can just put the heat to it.

[Graham.C]

If I ever try a full one again I'll mash in a kettle. That way if my temps are too low after adding the decoction back I can just put the heat to it.

That is exactly what Chris Colby from BYO recommends. Although I like that idea of a single step for the mash out, you would still get all the melanoidins without missing your mash temp. I read that a low Ph is key for limiting the tannin extraction, so a thick roasty mash might be a good way to skip doing the acid rests (or some salts). I feel like my first attempt might lean more in that direction then a full triple decoction.