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Old 06-04-2012, 01:13 PM   #1
HopRodGR
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Default Hochkurz Decoction Mash Rests

Hi All,

I'm going to be performing a Hochkurz double decoction for a Marzen I'm brewing in a couple weeks, and I'm trying to dial in my mash schedule, primarily to control my fermentability.

I've read all of Kai's writing on the topic and Noonan's chapter on decoction mashing, but my main question is, for those who have utilized this method before, do you perform a short 15-20 minute beta rest around 158 during the first decoction that is pulled?

My sense is that to hit the fermentability profile I'd like (using WLP833), I'll target a maltose rest at 145, wait 20 minutes before pulling the first decoction, and shoot for a total rest of around 45-50 minutes. However, to wait a sufficient amount of time before pulling the first decoction, give adequate time to let the temperature rise, and boil for 10 minutes, that really doesn't leave time for a rest in the middle, if I don't want the maltose rest sitting for more than my 45-50 minute target.

If my still novice understanding of the science of decoction mashing is correct, because the first decoction is thick, most of the enzymes are left behind in the liquid, and therefore a beta rest during the first decoction shouldn't be necessary since the second rest (dextrinization at 158) should allow the enzymes in the thin mash to convert the starches extracted during the first decoction boil. Full disclosure, my base grist is about 70% Pils/Vienna and 23% Light Munich.

For those who have used the Hochkurz method in the past, what have you done? Also, what length maltose rest have you found to work well for "maltier" styles such as Marzen or Maibocks?

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Old 06-04-2012, 01:28 PM   #2
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I did my first decoction mash a couple months back (a Marzen also). So I am by no means an expert, but here is how I did it and judging by my hydrometer samples, it turned out fantastic.

I doughed in thick at protein rest temps and did an infusion to reach the maltose rest ~144. Because of the lower temps, it is my understanding that it takes longer for the enzymes to convert so I just planned on holding it for 75 minutes. That decoction brought me to 158 so obviously I didn't need to hold for 15 minutes when I pulled my mash-out decoction. I just let it sit in the tun for that time.

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Old 06-04-2012, 01:33 PM   #3
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I recently brewed up two Marzens using the Hochkurz method. I will state that these were my first two decoctions and both beers are still lagering for approximately 2 months now. Both had the same mash schedule and were fermented using Wyeast 2124. I think I targeted just under 400 billion cells for the 5 gallon batch, so I did use starters. Take these numbers for what they are worth.

The first (50:40:10 Pils:Munich: Dark Munich) was 1.057 fermented down to 1.011 or about 80% attenuation. I mashed for 30 minutes at 147F, pulled my thick decoction, rested for 15 at 158F, boiled for 40 minutes, and returned to the mash to target 158F for another 30 minutes (fell short at 150). I really wanted to boil long to push it.

The second (80:20 Vienna: Dark Munich) was 1.062 fermented down to 1.011 (82% attenuation). My decoctions went better this time, hitting my final rest at 155F.

I don't remember how long it took to get my decoction to boil, but regardless, what I did not pull was sitting at 140-147F for at least 90 minutes.

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Old 06-04-2012, 02:35 PM   #4
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Quote:
Originally Posted by 14thstreet View Post
I recently brewed up two Marzens using the Hochkurz method. I will state that these were my first two decoctions and both beers are still lagering for approximately 2 months now. Both had the same mash schedule and were fermented using Wyeast 2124. I think I targeted just under 400 billion cells for the 5 gallon batch, so I did use starters. Take these numbers for what they are worth.

The first (50:40:10 Pils:Munich: Dark Munich) was 1.057 fermented down to 1.011 or about 80% attenuation. I mashed for 30 minutes at 147F, pulled my thick decoction, rested for 15 at 158F, boiled for 40 minutes, and returned to the mash to target 158F for another 30 minutes (fell short at 150). I really wanted to boil long to push it.

The second (80:20 Vienna: Dark Munich) was 1.062 fermented down to 1.011 (82% attenuation). My decoctions went better this time, hitting my final rest at 155F.

I don't remember how long it took to get my decoction to boil, but regardless, what I did not pull was sitting at 140-147F for at least 90 minutes.
If your results are any indication, it kind of supports my initial thoughts of just skipping the conversion rest in the first decoction so my maltose rest doesn't get too long, therefore producing less of it and a less fermentable wort. My mash will already be relatively thin (1.8-2.0 qt/lb) after my initial infusion from protein to maltose rest, so I should have plenty of enzymes in the thin mash to convert during the dextrinization rest at 158. I'm shooting for a 75% attenuation so it doesn't dry the beer out too much, and based on the fact that this is a double saccrification rest mash and the fact that I usually try to slightly overpitch the yeast in my lagers, I'm not too concerned about under-attenuation.
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Old 06-04-2012, 02:50 PM   #5
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If you look at that graph kai uses it definitely suggests an hour rest at 145-148 before bumping up to the 150s. The only way I see that really makes sense is if you are using a lot of unmalted grain because after 45-60 minutes everything should be converted. If you are using undermodified malt it is possible that after doing several decoctions prior to reaching saccrification temperatures you've denatured enough enzyme that it takes a very long time to complete the mash (and this might also be more broadly true on large, brewery-size mashes). However I can't see how the well modified grains we use at our mash size would see conversion for a full two hours.

What I normally do is when I reach the upper 140s (whether I dough in there or use prior decoctions to raise the temperature) I immediately pull the decoction and raise the temperature to 158. Let it sit for 10 minutes, then bring to a boil for another 10 minutes. Between those two temperature rests and time to raise the temperature you should be right around 30 minutes. Then add the decoction back to the full mash to get to 158F for a 30 minute rest. The last 15 minutes you can pull a decoction, bring to a boil for 10 minutes then add back to the mash to mashout.

I don't brew lagers but I do decoction mash my weizens and some Belgian beers. I have a modified decoction process I use for each of those that allow me to hit the lower rests for flavor components and then skip the protein rest as much as possible and go right to the 148F rest but not lose the opportunity to let the decoctions boil to develop the melanoidins and blow open the grains.

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Old 06-04-2012, 03:04 PM   #6
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Quote:
Originally Posted by ReverseApacheMaster View Post
If you look at that graph kai uses it definitely suggests an hour rest at 145-148 before bumping up to the 150s. The only way I see that really makes sense is if you are using a lot of unmalted grain because after 45-60 minutes everything should be converted.
As I understand it, the idea is to give both beta- and alpha- amylases the chance to work within their optimum ranges, to yield a near fully fermentable wort. The long low end rest will optimize beta, leaving a mixture of monosaccharides (fermentable) and small branched sugars (non-fermentable). The short high end rest then optimizes alpha, converting the branched sugars to fermentable sugars.
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Old 06-04-2012, 03:17 PM   #7
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Quote:
Originally Posted by ReverseApacheMaster View Post
If you look at that graph kai uses it definitely suggests an hour rest at 145-148 before bumping up to the 150s. The only way I see that really makes sense is if you are using a lot of unmalted grain because after 45-60 minutes everything should be converted. If you are using undermodified malt it is possible that after doing several decoctions prior to reaching saccrification temperatures you've denatured enough enzyme that it takes a very long time to complete the mash (and this might also be more broadly true on large, brewery-size mashes). However I can't see how the well modified grains we use at our mash size would see conversion for a full two hours.

What I normally do is when I reach the upper 140s (whether I dough in there or use prior decoctions to raise the temperature) I immediately pull the decoction and raise the temperature to 158. Let it sit for 10 minutes, then bring to a boil for another 10 minutes. Between those two temperature rests and time to raise the temperature you should be right around 30 minutes. Then add the decoction back to the full mash to get to 158F for a 30 minute rest. The last 15 minutes you can pull a decoction, bring to a boil for 10 minutes then add back to the mash to mashout.

I don't brew lagers but I do decoction mash my weizens and some Belgian beers. I have a modified decoction process I use for each of those that allow me to hit the lower rests for flavor components and then skip the protein rest as much as possible and go right to the 148F rest but not lose the opportunity to let the decoctions boil to develop the melanoidins and blow open the grains.
Ironically that is the other approach I considered taking, i.e. pulling the decoction almost immediately when I hit my maltose rest and then resting at 158 for 10-15 minutes. What was keeping me hesitant about doing that was not giving the decocted portion of the mash any time for maltose production, however that would support a less fermentable wort. Maybe a hybrid of the two would be worthwhile to try, pulling the first decoction at about 10 minutes, resting at 158 for 10, and boiling for 10. That should give plenty of time for the temperature rise and to keep the maltose rest under 1 hour. I'm not worried about the modification of my grain. The only possible cause for concern would be that my base is 55% Weyermann Pils, but I've heard numerous times that you can even single infusion mash with it without problems.
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Old 06-05-2012, 06:13 PM   #8
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Unless convinced otherwise, I think I'm going to give the schedule attached below a shot (assumes a 3F per minute rise during the decoctions). Surprisingly it will only add around an hour to the time of a typical 60 minute single infusion mash, and could be shorter if there is full conversion early in the dextrinization rest, which could move up the mashout decoction a few minutes. Based on the suggestions in this thread and the reading I've done, I get the sense this is a good target to try to reach the fermentability profile I'm shooting for.

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Old 06-05-2012, 07:29 PM   #9
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The mashout decoction doesn't need to be boiled for 10 minutes. I'd spend that time boiling the thick decoction.

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