Any reason not to do decoction mashes?

sideshow_ben · 05-15-2011, 03:48 PM

I usually get 68-72% efficiency using single infusions. I've done two turbid mashes and got 81% and 86%. Aside from taking more of my time, are there any reasons not to do decoction mashes for my beers?

wildwest450 · 05-15-2011, 04:00 PM

It depends on the style, and it's a lot of extra work. Only certain German lagers for me.

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headfullahops · 05-15-2011, 04:09 PM

I just pitched yesterday afternoon on a hefe mashed with a single decoction (mash-in at protein rest 130F, infuse to sacc rest 152F, and decoct to reach mash-out 170F). It didn't take a whole lot of extra time and there was a lot of coagulated protein on top of the grain bed after lautering. I'm interested to taste the results, if any.

**Golddiggie** · 05-15-2011, 04:13 PM

I plan on trying it with my next batch. I've been getting lower efficiencies since switching away from BIAB and want to get back into the mid to upper 70's (or better)... Right now, I'm in the ~65-72% range. If I can get back into the 78-82% range this way, I'll be very happy.

The way I see it, it's not that much more work to do a decoct step. I would like to know how long people let it rest before they start the sparging though. I plan on doing a 75 minute mash, decoct and boil, then return to the mash for 30 minutes before draining and sparging. I batch sparge, and will probably split the sparge amount into two parts for this coming brew. If all the extra steps (compared with what I've been doing) gives me a better extraction, without any negative impact on the brew, then it will become my process of choice. Just means I'll need to plan for the correct amount of time on brew day. So far it's been 5-6 hours from setup to cleanup. If this extends the day by another hour, I can easily live with that. Even two hours more will be ok.

I'm sure I'm not alone in being willing to take however long is needed to make great beer. I know of a brewer that does protein rests for all of his brews. Not just some, but all of them.

ArcaneXor · 05-15-2011, 04:14 PM

Around 70% efficiency is perfectly fine for homebrewing purposes. The difference between 70% and 85% is maybe $3 for a normal-strength beer in terms of ingredient cost.

Decoction mashing produces a fairly distinct flavor in the beer that is difficult to describe - a rich, dry maltiness that may be inappropriate for some styles. I personally only use it in some German beers or if I am mashing in my cooler mash tun and for some reason undershot my temperature by a large amount. But play with it and see if you like it!
Or look into step mashing, which boosts efficiency slightly compared to single infusions, but doesn't affect flavor nearly as much as a decoction.

**Golddiggie** · 05-15-2011, 04:26 PM

I use a cooler mash tun, so heating for a two step mash isn't very practical for me. I tried to do a mash out for my last brew, but efficiency was actually lower. Just trying to get the grain/mash up to 170F before draining and sparging.

I know I'm getting all the dough balls out, as well as mixing completely in the mash tun. I'm still puzzled by the reduction in efficiency compared with BIAB. I was using pretty much the same temperatures for that method.

I'm brewing styles from the British Isles currently. With a mocha porter on deck. The three recipes after that are an old ale, English barley wine and strong Scotch ale. Before I do any of those three, I need to get my efficiency more in line. I have two mash tuns [converted coolers] to use, a 40qt round and 70qt rectangle. So space won't be an issue for any batch. I was actually getting better efficiency in the larger cooler with the same amount of grain. Go figure. I lose about 1qt of water in the 70qt cooler, and 2qt in the 40qt cooler. Could that be the difference in my efficiencies?

One of the people at the LHBS does a decoct for all his batches. He then batch sparges (usually split in half) for all of his brews. He gets solid results, hitting his target time and again. Not sure what efficiency he's getting (he doesn't figure that out since he's done enough batches to know what he'll get)...

BigEd · 05-15-2011, 04:41 PM

Quote:

Originally Posted by sideshow_ben

I usually get 68-72% efficiency using single infusions. I've done two turbid mashes and got 81% and 86%. Aside from taking more of my time, are there any reasons not to do decoction mashes for my beers?

I do a lot of decoction mashes but I would not do one simply to increase conversion efficiency by a few percent. Checking the quality of your grain crush, the accuracy of your thermometers, your water profile and brewing salt additions for the styles being brewed would be the first things to do IMO. As has already been noted decoction mashing can produce some nice flavor elements but again to echo a comment above it isn't necessarily appropriate for every type of beer.

**Golddiggie** · 05-15-2011, 05:00 PM

Thinking about it more... I know the crush on my last brew was bad/poor (from the LHBS)... Others commented (after the National Home-Brew day event) that they either had the grain double milled there, and/or got poor efficiencies. So, I'm going to tweak my mill to a slightly smaller crush size (it's at the default .039") and try with a mash-out step instead of the decoct. If I can get in the mid 70's that way (or better) then that will become my default process. Obviously adjusting it as needed for recipes/styles...

I have to wonder what people are really doing when they post up getting mid-80's (or above) for efficiencies. Or are they really getting lower numbers and just lie about it?

**GuldTuborg** · 05-15-2011, 05:58 PM

Quote:

Originally Posted by Golddiggie

I lose about 1qt of water in the 70qt cooler, and 2qt in the 40qt cooler. Could that be the difference in my efficiencies?

To what do you lose this water? I'm confused on that point. How do you sparge?

**Golddiggie** · 05-15-2011, 06:10 PM

Quote:

Originally Posted by GuldTuborg

To what do you lose this water? I'm confused on that point. How do you sparge?

I 'lose' it since that's how much is left over after whatever can drain out drains out... So 'mash tun loss' is probably a better way to think about it. I've done 'dry' tests of both my mash tun coolers, pouring about a gallon of water in and then letting them drain as normal. Once that's done, I dump the remaining water out and measure that. I enter that info into BeerSmith for my hardware, so that it offsets that volume loss when figuring out how much water I need...

I'm batch sparging. So far, I'm using a single batch sparge with my brews. If there's enough sparge water to split, and properly rinse the grain, then I'll do that. IF I decoct, the sparge will be large enough to split (for the recipe on deck). IF I mash-out, then the sparge volume will not be enough to split into two parts.

Personally, I'm just looking to get my efficiency into the 75-80% range with my typical gravity brews. I'm holding off on brewing something big until I have this ironed out.