My First Decoction Experience

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chewyheel

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I recently finished reading the Vienna Lager book by Andreas Krennmair, which I highly recommend, and it inspired me to attempt a decoction in honor of the traditional brewing method. This recipe was adapted from one in the book, which represents a more modern interpretation of the style. I basically subbed Perle for Saaz because I love Perle.

I kept the grain bill simple with 9 pounds of Mecca Grade Vanora and 2 ounces of midnight wheat for a little color. Amber balanced water profile per Bru'n Water so I had to add 2 grams gypsum and 1.5 grams CaCl and some Campden to take out the chlorine, resulting in a mash pH of 5.41 15 grams of Perle first wort hop for a 70 minute boil and 21 grams in the whirlpool for 10 minutes at roughly 180 degrees. Fermented with 34/70 at 60 degrees.

Let's get to the fun stuff, I mashed in with 5 gallons of water to raise temp to 100 degrees then pulled what I thought was a tick decoction of approximately 2/3 of the mash, which was almost 4 gallons. Raised the decoction to 159 then rested for 20 minutes, then raised it to a boil for 10 minutes, and added it back to the main mash. This is where things got wonky. The main mash was supposed to settle back at 149, but mine clocked in at 168! Fortunately, I had some cold water on hand just in case this happened, so I added about half a gallon of cold water to bring the temp down to 150, where it rested for 10 minutes. I then pulled a thin decoction of 2.5 gallons and boiled it for 10 minutes and added it back to the main mash to raise temp to 167, and rested for 10 more minutes. Refractometer reading showed a pre boil OG of 1.046, instead of 1.036 as predicted, then proceeded with the boil and added 3/4 gallon cold water at end of the boil to bring OG down to 1.049.

A couple of observations
My efficiency was way higher than usual, I typically get around 75%, but this mash resulted in 92% efficiency.
I added about an hour and a half to my usual brew day. My typical set up is no sparge BIAB, so my brew day is usually around 4 hours.
It's still in the fermentor, so I don't have a OG yet, but I'm betting that I had a pretty highly fermentable wort, so I hope it doesn't finish too dry. I routinely get at least 80% attenuation with 34/70.
I think I over shot my initial temp after adding back my first decoction because my decoction was too big, or I pulled too much water with it and it wasn't thick enough, or a bit of both. I'd love some feedback if anyone has an answer for this.
Has anyone else that's done a decoction had similar results? Not sure if I'll attempt another one, we'll see how the beer turns out first but I'm glad I tried it, a good learning experience at the least.
 
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cactusgarrett

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I always get higher than typical pre-boil SG when i decoct. I think it's just the nature of the beast. I never remember to account for it though; ha! But also, it's minor but I've started accounting for it since I sometimes boil the decoction for upwards of 30 min (depending on the recipe): you need to account for evaporation during decoction. Obviously the longer you boil the more you lose, but that evaporation will impact your pre-boil SG slightly.

You did well in adjusting on the fly - even after a good amount of experience with decoction, it never goes without a hitch for me. You were almost there - all you needed to do was not add the entire decoction back. It's best to pull more than you expect to need and just not add it all back for the reason you saw - overshooting your next step temp. That said, it's easier to cool than it is to heat (without a direct fire mash), so overshooting a bit is the lesser of two weevils in my opinion.

Once you get more versed in it, it comes much easier. I do a cooler MLT and burner boil, and the only time performing a decoction adds to my brew day is related to cleaning, since the decoction portion takes place concurrently with the tail end of the main mash resting. I never thought I'd continue with it, but it's become my standard procedure with nearly all my German style brews (which is the majority of them), as I love what it brings to the table flavor-wise.
 

Vale71

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It's perfectly normal to get higher efficiency when doing decoctions. As a matter of fact it's one of the collateral advantages of the process.

I would encourage you to be less timid in your decoction steps, especially if brewing darker, maltier beer style. Do not be afraid to boil more than a handful of minutes but experiment all the way to one hour or more, you'll be amazed by how much the beer changes with long decoctions.
 

Holden Caulfield

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My observations of doing decoctions (just did another on Saturday)
  1. Yes - the mash duration gets longer, depending on the number of steps, length of rests, decoction boil times, etc.
  2. Efficiency goes way up versus a single infusion or step as you experienced.
  3. Sparging gets more difficult, so it takes longer and the top of the grain bed has to be raked more often to allow the wort to flow through the "Teig". Raking the top of the grain bed is the first thing I do when my sparge gets very slow or stuck - it has worked every time.
  4. Formulas that calculate the exact quantity of decoction to pull to raise to next temperature often end up undershooting the target temperature. I believe this is due to not factoring the mashtun temperature loss that occurs when pulling the decoction. If using these formulas, the amount should be uplifted to ensure enough decoction is pulled. Then, when adding back, the temperature of the mash should be checked before adding it all back to ensure the target temp is not overshot. Also, I have observed that the decoction uplift factor needs to go up with each step as the temperature loss from pulling the decoction gets greater as the mash temperature goes up. BTW, all of this is moot if your mashtun can be heated - I use a cooler.
  5. As far as making better beer - can't say, as I have never done a comparison. All I know is that making a beer with Melanoidin malt doesn't replicate the flavor in Pilsner Urquell:).
Below is a snapshot of the decoction plan I did last weekend - calculations use Palmer's formulas. Everything was spot on except hitting the second decoction target temp which I believe was because the uplift factor I use is the same across every decoction (alternatively, the decoction temp loss factor could be made different for each decoction). However, since the second decoction was pulled at 146 vs 127 (note, the initial temperatures have a temperature drop built in so they will seem low) the mashtun lost a lot more energy so the uplift should be larger. I will be updating my program to allow for this.

it inspired me to attempt a decoction in honor of the traditional brewing method.
^Like. Its a great way to connect with the past, refine your processes, and continue to grow as a brewer.

1610732269579.png
 

TheMadKing

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It's perfectly normal to get higher efficiency when doing decoctions. As a matter of fact it's one of the collateral advantages of the process.

I would encourage you to be less timid in your decoction steps, especially if brewing darker, maltier beer style. Do not be afraid to boil more than a handful of minutes but experiment all the way to one hour or more, you'll be amazed by how much the beer changes with long decoctions.
+1 to this - my favorite marzen recipe involved a 45 minute "bake" (boil in the oven) of some very low liquid decoction (mostly grain)
 

riceral

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+1 to this - my favorite marzen recipe involved a 45 minute "bake" (boil in the oven) of some very low liquid decoction (mostly grain) for 45 minutes.
Can you explain this for me?

If I understand right, you use a mostly grain portion of the mash (with very little liquid) in the oven at 200*/250*/300* for 45 minutes. Or do you actually boil the grains in the oven? What temperature do you set the oven at for this step? Then the decoded grains goes back in the mash and carry on as usual.

This sounds interesting.
 

bu_gee

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+1 to this - my favorite marzen recipe involved a 45 minute "bake" (boil in the oven) of some very low liquid decoction (mostly grain)
Can you share your recipe? Marzens are my very favorite lager and I am preparing now for my March brew. I do a decoction as well, but following the same technique every time has become, well, a bit boring.
 

TheMadKing

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Can you explain this for me?

If I understand right, you use a mostly grain portion of the mash (with very little liquid) in the oven at 200*/250*/300* for 45 minutes. Or do you actually boil the grains in the oven? What temperature do you set the oven at for this step? Then the decoded grains goes back in the mash and carry on as usual.

This sounds interesting.
Yep I pull about 2-3 gallons by volume using a strainer so it's mostly grain, put it on the stove and bring it up to a boil. Then it goes into the over where I bake it for 45 minutes at 350 with a lid on. I stir it once in the middle

Then pour it back into the main mash for the mashout

My Märzen recipe is

6lb Munich
6lb Vienna
8 oz Caramunich III (this is optional, I've done it both ways. It makes it a hair sweeter and more complex)

Mash using a 2 step decoction
143 beta
156 alpha
168 mashout
with the baking happening on the final step from alpha rest to mashout
OG 1.057

120 minute boil
0.5 oz magnum @60 min
0.75 oz spalter @0 min

Wyeast Oktoberfest lager blend
 

riceral

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Yep I pull about 2-3 gallons by volume using a strainer so it's mostly grain, put it on the stove and bring it up to a boil. Then it goes into the over where I bake it for 45 minutes at 350 with a lid on. I stir it once in the middle

Then pour it back into the main mash for the mashout
Thanks King. I might have to give this a try.
 
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chewyheel

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Thanks for all the feedback. I think I'll definitely try an extended boil time on the decoction next time. It wasn't as challenging as I expected and the second time will go smoother I'm sure, I'll just have to account for the increase in efficiency.
 
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Yep I pull about 2-3 gallons by volume using a strainer so it's mostly grain, put it on the stove and bring it up to a boil. Then it goes into the over where I bake it for 45 minutes at 350 with a lid on. I stir it once in the middle

Then pour it back into the main mash for the mashout

My Märzen recipe is

6lb Munich
6lb Vienna
8 oz Caramunich III (this is optional, I've done it both ways. It makes it a hair sweeter and more complex)

Mash using a 2 step decoction
143 beta
156 alpha
168 mashout
with the baking happening on the final step from alpha rest to mashout
OG 1.057

120 minute boil
0.5 oz magnum @60 min
0.75 oz spalter @0 min

Wyeast Oktoberfest lager blend
I am fascinated by this. If I may clarify:

Your entire mash was brought up to 143 (or mashed in to achieve 143). How long did it rest at 143 before you pulled out grain? I am assuming that the enzymes keep working while you are bringing to boil and then baking the grain, but what about the sugars in the grain (which goes back to question #1-how long do you leave it before decoction to make sure starch transforms)?
 

TheMadKing

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I am fascinated by this. If I may clarify:

Your entire mash was brought up to 143 (or mashed in to achieve 143). How long did it rest at 143 before you pulled out grain? I am assuming that the enzymes keep working while you are bringing to boil and then baking the grain, but what about the sugars in the grain (which goes back to question #1-how long do you leave it before decoction to make sure starch transforms)?
I mashed in to achieve 143

I let it rest 10 mins or so before pulling the first decoction. The process of getting up to a boil on the stove takes about 20 minutes so a good amount of conversion is happening during that process. You are also adding back to the main mash which is full of enzymes still and will go to work on the decoction again, as soon as it's added back.

My efficiency goes up with decoction mashing due mostly to the total time spent mashing probably. But there is plenty of time at each step and in between to allow conversion to occur.
 

Vale71

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My efficiency goes up with decoction mashing due mostly to the total time spent mashing probably. But there is plenty of time at each step and in between to allow conversion to occur.
That and also the boiling of some of the grain opens up more starch making it accessible to enzymes.

The longer rest at saccharification temperature has a limited effect since enzymes denature rather quicly at temperatures that are within the optimal range for the enzyme.
 

jerrylotto

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In an attempt to revive this thread, I'm planning my first decoction experiment as a triple decoction for a pilsner recipe with 10# 2-row and was thinking that I would pull about 1/3 per step. The other thing is that I have a recirculating mash tun so my plan is to stop recirculation, let settle and pull the top 1/3 (thickest) for each of the boil steps. After each boil, I was going to float the kettle in a water bath to get the temp down to the next step range. That also means that when I add it back I'm going to have to stir the crap out of it to get it all mixed back in for the next third. I welcome any experienced brewers comments.
 

BigEd

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If you're going to the trouble of brewing a decocted pilsner at least buy some decent European pilsner malt to make it with. While the 1/3 quantity is the basic rule of thumb you may want to consider pulling a slightly larger amount, up to 40%, as coming up short on temperature is not uncommon for beginners in the process. Having both cold and hot (close to boiling) water on hand for quick temperature adjustments can be reassuring.

I'm not sure I understand what the floating kettle to lower temperature is all about. Stirring the crap out of it is part of the program. You will need to very thoroughly mix the boiled pull with the main mash to get the temperature as uniform as possible. If you hit the targets you'll get a +20F temperature rise with a decoction step. FWIW I start at 128F/54C, move to 148F/65C, and then to mash-out as the third step.
 

cactusgarrett

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let settle and pull the top 1/3 (thickest)
Do you mean the bottom? If you let settle, the grain will settle to the bottom.

After each boil, I was going to float the kettle in a water bath to get the temp down to the next step range.
I'm not understanding this step, and have never seen something like this done. You adding the contents of the kettle back to the mash tun at boiling temps is what brings the mash tun up to the next sacc rest step. I must be missing some integral step in your process...
 

cactusgarrett

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you may want to consider pulling a slightly larger amount,
This is a key point to consider. I usually get calculators to tell me how much to pull (online, beersmith, etc.) but in actuality it takes me pulling nearly ALL of the grain (as a thick pull) and adding it all back to hit my 144F -> 160F step.
 

jerrylotto

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If you're going to the trouble of brewing a decocted pilsner at least buy some decent European pilsner malt to make it with. While the 1/3 quantity is the basic rule of thumb you may want to consider pulling a slightly larger amount, up to 40%, as coming up short on temperature is not uncommon for beginners in the process. Having both cold and hot (close to boiling) water on hand for quick temperature adjustments can be reassuring.

I'm not sure I understand what the floating kettle to lower temperature is all about. Stirring the crap out of it is part of the program. You will need to very thoroughly mix the boiled pull with the main mash to get the temperature as uniform as possible. If you hit the targets you'll get a +20F temperature rise with a decoction step. FWIW I start at 128F/54C, move to 148F/65C, and then to mash-out as the third step.
I was concerned about adding the third back near boiling temps so I was planning to cool the decoction back to the step temp and then heat the entire mash to the next step after adding it back and mixing. On the other hand, I see your point. Say 2/3 of the mash at 144F and 1/3 at 204F would result in a +20F step after combining them without any additional heating. So it works fine even with a passive mash tun, but the recirculation pump on my Mash&Boil make it pretty simple to set and maintain each step mash temp. The mash tun I use has an insert that holds all of the grain with false bottom and about an inch of free space below and 1/2" free space around, so when I stop the recirc, the liquid drains down enough so the top of the mash will be the "thickest."
 

jerrylotto

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If you're going to the trouble of brewing a decocted pilsner at least buy some decent European pilsner malt to make it with.
Pilsner is German 2-row malt and is sometimes modified to a slightly lesser degree and is kilned to an extremely light color. American 2-row tends to be a little higher in protein, slightly better converted than some German malts and kilned just a shade darker. I'm not really seeing enough of a difference to matter.
 

Holden Caulfield

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I was concerned about adding the third back near boiling temps so I was planning to cool the decoction back to the step temp and then heat the entire mash to the next step after adding it back and mixing.
^So you will be essentially relying on a heating source rather than the decoction to raise to the next step. If so,
  • As the quantity of mash is not critical for raising to the next temperature the purpose of the decoction is to coax only decoction flavor, so to simply, pulling 1/3 of the mash should work just fine. Pick a starting mash thickness of 1.5 - 2.0 and pull as thick a mash (mostly grain) as possible with enough liquid to boil without scorching
  • You really don't need to cool the decoction before adding it back - just do it slowly and mix gently while adding. Also, check the temperature periodically and hold back some of the decoction if not needed. Just add that back after it cools.
Regarding decoction formulas in brewing software - while the calculations are based on science and in a perfect process they would probably be fairly accurate, they do not account for energy loss during the pulling and adding back part of the process. This energy loss can be significant and will vary dependent on a homebrewers process. It also becomes more significant as the mash temperature steps higher. As others mentions, a best practice is to pull extra (I use 25 - 40%) to account for this energy loss dependent on which step (higher temps steps lose more energy during pull and add back)
 

cactusgarrett

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they do not account for energy loss during the pulling and adding back part of the process. This energy loss can be significant and will vary dependent on a homebrewers process.
This is monstrous and why I always just pull nearly the entire grainbed. Weather and (relatively) cold "pulling equipment" (ie. ladles, pitchers, etc.) always drop my main mash temp and slowly adding the decoction back always takes longer than it should. Get a feel for your process and replicate it. Get to a place where you can rely on repetition.
 

BigEd

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Pilsner is German 2-row malt and is sometimes modified to a slightly lesser degree and is kilned to an extremely light color. American 2-row tends to be a little higher in protein, slightly better converted than some German malts and kilned just a shade darker. I'm not really seeing enough of a difference to matter.
All brewing barley save for North American 6-row is two row. It does not all taste the same. "Two-row" merely describes the way the corns grow on the stalk head.
 

jerrylotto

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All brewing barley save for North American 6-row is two row. It does not all taste the same. "Two-row" merely describes the way the corns grow on the stalk head.
Good point - I should have been more specific: Rahr Standard 2-row pale is what I'm planning to use.
 

BigEd

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Good point - I should have been more specific: Rahr Standard 2-row pale is what I'm planning to use.

Ok I'm going to show my old man, blunt side here but unless you can't taste the difference, which I suspect you can since you are jumping into a decoction mash, do yourself and your beer a favor and but some good German Pilsner malt for that brew. It will make a difference.
 
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