decoction discussion with a pro brewer

[nathan]

Tomorrow I do a decoction on the hefe, but I need to rework it. I had read of others using a decoction to reach mash-out temp of 170F. I discussed this with one of the former brewers of Molson, and after he pondered it he recommended decocting to a lower temp and giving it 15 minutes or so. His thought was that any steely ends or starches that might have still been undissolved and liberated by the decoction could use the enzymatic activity back in the mash. If your malt had a lot starch from this, you could end up with haze. Clearly more of an issue for a large brewery, but cool that he would discuss it with me. He also gave me some information about the power requirements for decoctions which really illuminate why it is a dying art at the professional scale. It's about 2 times the energy of a normal mega-brewery mash for them to do it.

what do you think? Maybe come back at 158 for 15? Heck, could immediately pull a second to get to 170.

 

[Awfers]

Interesting question you pose.

In all my decoction experience, I never used it to raise to mashout temp, so I can't help you there.

I can see where he would have some worries, as the liberated starches aren't converted as the enzymes are killed when you add the decocted mash back in. Hence longish chains of unfermentable starches..

The question really is, do you care about the possible risk to clarity? Or do you want to test a process? Frankly, if you are referring to a wheat beer, then clarity really isn't an issue, is it?

Cheers,
Awfers

 

[z987k]

Interesting, and I would agree with him, in most of the decoctions I've read people aren't mashing out with it, just raising temps to certain rest temps, but not a mash out.

 

[bradsul]

I've done a mash out decoction boil (15 minutes) for the last 6 or 7 months and I've not had any clarity issues. I find I actually get more of the gummy proteins sitting on top of the mash bed after sparging, those are the same ones that would normally end up in the kettle.

Check out Kaiser's videos and posts on the subject for tons of great info.

 

[k1v1116]

I tried a decoction mash out on a kolsch a few months ago and while I had clarity problems I also skipped the protein rest on that brew and I think that was the cause of the clarity issues but in any case a little polyclar and a week or two extra in the secondary fixed that problem. I think the decoction mash out really helped this beer, the final gravity was 1.004 and the kolsch yeast I used created almost no esters. Without the grain flavor I think the decoction added, this beer would have tasted like BMC.

 

[Awfers]

I did a bit of research last night in Kunze, and I find it odd that the Molson guys double their energy consumption to do a decoction, as Kunze puts it, the average increase in energy consumption is 20% due to the fact that without decoction you still need to expend energy to heat the entire mash.

Granted, I know nothing of Molson's setup, but double the energy consumption is a strange figure.

Cheers,
Awfers

 

[WBC]

To reach mashout only heat liquid from the mash to the temperature you need (usually boiling). Add slowly to the main mash while stiring to obtain mashout temperature. Save the remaining liquid and cool to the mashout temperature and add back to the mash.

 

[nathan]

I don't think Molson is doing this, the information was general energy requirement info.

I wasn't worried about clarity on a hefe, of course, just practicing the technique.

To be sure, though, a starch test in the mash before returning the 1st decoction was almost nonreactive, and after the return, was more reactive, so there is some starch liberation. I have no empirical data on how that might affect clarity, it was just the experience of a pro brewer that starch = haze, in our discussion.

In any case, I also learned that I will need to adjust and decoct more or get beersmith to know my equipment better, so I can reach the temps more easily.

It was a hoot!

 

[Kaiser]

I know where he is coming from. Decoction can and most likely will release additional starches. How much will depend on the modification of the malt. This is one reason why the mash-out deoction is a thin decoction as you want to minimize that starch release.

But when doing only one decoction, there is enough enzymatic activity left at mash out temps (170F or 76C) to convert these starches. Remember mash out is not supposed to kill all enzymes. It kills beta amylase but keeps alpha amlylase active to convert starches released during mash-out and lauter. As a matter of fact I recently ran an experiment to show that.

So keep the mash-out deoction fairly thin and aim for 170 as the mash-out temp. That's what I do and I'm fine. I think even a thick decoction will work with todays malts. When in doubt, do an iodine test.

Kai