Decoction questions:

Hey folks. I'm planning to brew a 16 gallon batch of Oktoberfest Lager this week, and I'm thinking about doing my first decoction. My plan is to mash in and hold at 131 for 20 minutes, then pull the decoction, boil, and add to the MLT to achieve 152 in the full mash. I've read a bunch of stuff on HBT, bust still have a few questions about what I can do and decoctions in general. Here goes:

1. When I put my numbers into BeerSmith, it told me I should pull 13 quarts of mash for the decoction. Has anyone been able to boil that amount of mash on a propane kitchen stovetop? My brew rig is all electric, so I don't have a dedicated burner for decoctions (yet).

2. While I'm boiling my decoction upstairs on the stovetop, what happens to the remaining mash/liquid in my MLT? Should I continue to recirculate (I have a HERMS) at 131?

3. What if it takes a long time to boil the mash on the stove top? Will anything detrimental happen to the liquid in the MLT?

THanks for the help. If all else fails, I'll just go 131 for 30 min and 152 for 60 with a 10 minute mash out and call it a day.

erikrocks said:

Hey folks. I'm planning to brew a 16 gallon batch of Oktoberfest Lager this week, and I'm thinking about doing my first decoction. My plan is to mash in and hold at 131 for 20 minutes, then pull the decoction, boil, and add to the MLT to achieve 152 in the full mash. I've read a bunch of stuff on HBT, bust still have a few questions about what I can do and decoctions in general. Here goes:

1. When I put my numbers into BeerSmith, it told me I should pull 13 quarts of mash for the decoction. Has anyone been able to boil that amount of mash on a propane kitchen stovetop? My brew rig is all electric, so I don't have a dedicated burner for decoctions (yet).

2. While I'm boiling my decoction upstairs on the stovetop, what happens to the remaining mash/liquid in my MLT? Should I continue to recirculate (I have a HERMS) at 131?

3. What if it takes a long time to boil the mash on the stove top? Will anything detrimental happen to the liquid in the MLT?

THanks for the help. If all else fails, I'll just go 131 for 30 min and 152 for 60 with a 10 minute mash out and call it a day.

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1. I wouldn't wait 20 minutes and then pull the decoction- you'd be at 131 for a LONG time! I'd mash in, stir well, and then proceed to pull a decoction. On my stovetop, I can boil a large volume but you may need to try it first to see if you can do it. If it takes an hour to bring 13 quarts to a boil, for example, it won't work for you with that volume.

2. Yes.

3. Yes- you don't want to leave the mash too long at a protein rest temp.

Thanks. How much can you boil on your stovetop? I remember when I started out three years ago that 7 gallons of wort would not boil on my stovetop. I'm guessng 13 gallons of mash will be difficult as well.

When I do a single decoction I begin with the batch split 60/40. I bring the 60% amount to the initial rest and leave it there while I bring the remaining 40% to a boil and hold the boil for 10 minutes. I then combine the two and continue with the sacch rest. With a HERMS you'll have no trouble tweeking your sacch rest to whatever temp you want.

erikrocks said:

Thanks. How much can you boil on your stovetop? I remember when I started out three years ago that 7 gallons of wort would not boil on my stovetop. I'm guessng 13 gallons of mash will be difficult as well.

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I can easily boil 7 gallons on my stovetop, but it takes a long time to get there (like an hour!).

You can break up the decoctions, or use a propane burner. I know that when I do decoctions now (since I have an electric system) I wouldn't go bigger than a 5 gallon batch since I'm also using my stove for decoctions. I brew all indoors.

well, first, we're talking 13 qts, which is 4.25 gallons. Luckily for the sake of the stove, you'll be bringing this to a boil from 130*F instead of 60*F.

Yooper, care to explain more of why that extended protein rest is bad?

cockybitz said:

Yooper, care to explain more of why that extended protein rest is bad?

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Almost no malt these days really requires a protein rest. They're almiost all hiughly modified, which means that in essence the protein rest has been done by the maltster. By remaining at a protein rest temp too long, you can actually break down the proteins that give you beer foam and body. I've done it and ended up with a thin, headless beer.

Denny said:

Almost no malt these days really requires a protein rest. They're almiost all hiughly modified, which means that in essence the protein rest has been done by the maltster. By remaining at a protein rest temp too long, you can actually break down the proteins that give you beer foam and body. I've done it and ended up with a thin, headless beer.

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Yep.

I think there is one maltster who makes a slightly undermodified malt. The rest are fully modified. By staying too long at a protein rest (even a higher temp one like I typically do), you get the results Denny explained.

Why the decoction in the first place? If you just want a richer caramelly malt character, you could cheat with a longer boil (an extra hour or so, and adjust your pre boil volume), or play with the specialty grains, adding some Carafa II Roast malt, or some extra Aromatic (dark Munich ) malt. Also, you can pull some of the first runnings and boil it down in a separate pot to get some kettle carmalization, and then return it to the boil. Be careful with this as it will effect your color.
If you just want to decoct, maybe make a smaller batch?

You're just going to have to get in there and get your hands dirty. I made 10 gallons of Czech Pilsner at the beginning of the year, I mashed in at 133. Pulled around 2/3s out and brought it to 148 degrees and let it sit there to convert for about 20 minutes(I don't know if this was necessary but it made sense to me) then I gave it a good long boil, until the grains were almost completely dry and sticky with caramel. The whole time my cooler was I the 130's, probably for a good hour. I dumped my mash back in and it came it 154. The result was a burnished gold pilsner that after 2 months of bottle conditioning held the most gorgeous head I have ever seen. It was almost rubbery. And dispute being quite light in color the beer had a depth of malt flavor that melanoidin malt will never replace. I'm pissed that it's gone, I just sent my last 2 bottles off in a trade.

chessking said:

Why the decoction in the first place? If you just want a richer caramelly malt character, you could cheat with a longer boil (an extra hour or so, and adjust your pre boil volume), or play with the specialty grains, adding some Carafa II Roast malt, or some extra Aromatic (dark Munich ) malt. Also, you can pull some of the first runnings and boil it down in a separate pot to get some kettle carmalization, and then return it to the boil. Be careful with this as it will effect your color.
If you just want to decoct, maybe make a smaller batch?

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There is no substitution for a decoction mash, I don't care what any of the brewing gurus have to say. I've done 3 so far and it imparts a totally unique quality that can't be gained from specialty malts.

bottlebomber said:

There is no substitution for a decoction mash, I don't care what any of the brewing gurus have to say. I've done 3 so far and it imparts a totally unique quality that can't be gained from specialty malts.

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I agree, but if the OP finds he cannot effectively perform a decoction on that scale, than there are other options.

FWIW, when I do a decoction or step mash (NOT very often since I don't think either justifies the effort), I mash in at beta temps (145ish) and then go to 158-160 for the decoction or step infusion. There's no reason to not just skip the protein rest.

Denny said:

FWIW, when I do a decoction or step mash (NOT very often since I don't think either justifies the effort), I mash in at beta temps (145ish) and then go to 158-160 for the decoction or step infusion. There's no reason to not just skip the protein rest.

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This is probably the best schedule for OP, unless OP needs an acid rest. It takes a huge decoction to get the mash from 89F to 145F and taking so much out of the mash makes the acid rest less effective since so little is getting acidified. Makes way more sense to add some lactic acid or acid malt and just start at 145F.

Denny said:

FWIW, when I do a decoction or step mash (NOT very often since I don't think either justifies the effort), I mash in at beta temps (145ish) and then go to 158-160 for the decoction or step infusion. There's no reason to not just skip the protein rest.

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Denny, correct me if I'm wrong, but haven't you done some studies, or experiments on the effectiveness of decoction? And if I remember correctly the difference was minimal.

chessking said:

Denny, correct me if I'm wrong, but haven't you done some studies, or experiments on the effectiveness of decoction? And if I remember correctly the difference was minimal.

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Yep, I have. It's at http://www.ahaconference.org/wp-content/uploads/presentations/2008/DennyConn.pdf starting on pg. 25. If you add together the people who preferred the non decocted beers and the people who had no preference, it was more than those who preferred the decocted beers. Pretty much indicates that there's no guarantee that decoction will make a better beer.

BTW, on pg. 29 there are the results of a FWH experiment I did.

Denny said:

FWIW, when I do a decoction or step mash (NOT very often since I don't think either justifies the effort), I mash in at beta temps (145ish) and then go to 158-160 for the decoction or step infusion. There's no reason to not just skip the protein rest.

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That makes sense...

Denny said:

Yep, I have. It's at http://www.ahaconference.org/wp-content/uploads/presentations/2008/DennyConn.pdf starting on pg. 25. If you add together the people who preferred the non decocted beers and the people who had no preference, it was more than those who preferred the decocted beers. Pretty much indicates that there's no guarantee that decoction will make a better beer.

BTW, on pg. 29 there are the results of a FWH experiment I did.

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Just finished reading through this. Thanks for the info Denny.

Thanks for all the feedback. I actually ended up ditching the decoction, holding at 128 for 20 minutes and 151 for 60 minutes, and boiling for almost 2 hours.

First of all, the reason I wanted to do a protein rest is head retention. It's funny, because different authors disagree wholeheartedly about whether a protein rest is beneficial or detrimental. Palmer writes that a protein rest at around 128 will help head retention, even with modified malts, while Gordon Strong writes the opposite. Since I was using a decent amount of Munich malt for the OKtoberfest, I thought I'd use the protein rest for this go around.

As for the decoction...I think I just want to try it at some point. Is it necessary? Well, again, Palmer/Jamil and G-Strong disagree. I also read the study that one of our own posters conducted here, with the outcome being that a decoction really only affects efficiency (which I'm not really looking for, since I'm already around 80%).

I am going to brew a hefeweizen next month, so the decoction question will rear its ugly head again for that brew. I was able to resurrect my old Bayou Classic propane burner, so I might actually decoct for that beer. Who knows. Thanks again for the input. It's really a great debate.

Dont be discuraged from doing a decoction. You should try it of course if for no other reason than to be familiar w/ the process. Ocasionaly I BIAB when brewing wheat or rye beers, as lauderering can be difficult. I use a decoction to move from beta glucan to protein to sac rest. Decoction is a means to change temperature . I don't do it necessarily for flavor difference although I'm sure there is some effect. Having done it a few times w/ BIAB I am now confident that if for example i miss my target temp by a large margin for whatever reason, I will quickly pull some mash, boil and replace to raise the mash temp. I don't have to think too hard about the procedure. Perhaps though if you want to give it a shot, try it on a 5 gal batch.