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Annotated Brew-Day: Double Decoction

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Cap'n Jewbeard

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Well, tomorrow is brew day! Our crew's 1st Double-D Beer, and maybe our 4th AG brew overall (numerous partial-mashes done as well over the years).

I'm pretty excited about the recipe and the decoction process, so I want to document it here for posterity. Feel free to jump in with questions/comments/suggestions, as I definitely am not claiming expertise here. At least I'll have a good diagnostic to review if it goes boink.

The beer is our "April-zen", an Oktoberfest that will hopefully be on the drier side of the style.

Recipe:
5 lb Pilsener
4 lb Munich malt
3 lb Vienna malt
1/2 lb Crystal 20
1/3 lb Caramunich

1 oz. Hallertau - 60 min
1 oz. Hallertau - 30 min
0.5 oz Saaz - 2 min

Yeast: WLP 838 Southern German Lager
Yeast Starter - 1 qt, gravity = 1.42, 1 day fermenting

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Tonight, the night before brew-night, I've laid things out ahead of time. The most useful thing I've done tonight is measure out all the water I'll need and put it in two pots ready for the fire.

In my old brew-pot (which is now my hot liquor tank because it's thin as crap and prone to scorching), I've got 5 gallons which should cover the 4.5 gallons of sparge water and another 2 quarts to top up the temp if needed.

In my new pot (32-quart Polar Ware Brewrite Kettle), there's 15 quarts of strike water ready to be heated. This pot will also be my decoction pot since, god-willing, it won't scorch as bad as my old one.

With great foresight, I've also put 10 bottles of our team's Maibock in the fridge. Gonna be 70 degrees tomorrow, perfect weather for it.

Time for some sleep - more in the morning!
 
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Cap'n Jewbeard

Cap'n Jewbeard

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Sweet, CastleHollow, let us know how it goes!

I heated the strike water at about 11:20 and it's ready to go. As of now, the first problem cropped up: I tried to fix a small leak in the valve on the mash tun (just had some hot water in it to pre-heat the insulation), and now we need to disassemble the valve altogether. Sigh. Hopefully nothing some of that white tape can't fix.

Other than that, pretty excited! Some pics to show the setup:

First, the leaky mash tun: J'accuse!


Next, the bazooka tube inside. The false-bottom was way expensive for this, and so far I've been pretty happy with the tube. However, I suspect it's partly or entirely responsible for the leak.


Various vessels: measuring cups, sanitation bucket, brew paddle:


The boiling setup: New kettle, propane tank, thermometer.
 
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Cap'n Jewbeard

Cap'n Jewbeard

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So! Litany of woes happened today...

1) We "fixed" the leaky MLT by tightening the spigot with a couple of wrenches.
2) All was going pretty well, until we were stirring in the 1st decoction. Then? THE SCREEN TUBE FELL OUT OF ITS COLLAR. At that point we were pretty much hosed, because there was no way to keep the grains from clogging the spigot, which they inevitably did. So after mash-out we had to scoop up all the grains into a big nylon grain bag and try to "sparge" them directly into the kettle by pouring water over the bag.
3) We missed almost all the temps. This tends to happen to me in AG brews, and I don't know if it's because of my setup, or the thermometer is no good, or what.

The tale of woe begins in the next post. (Although we did get enough to boil, at roughly the right pre-boil OG, so maybe there's hope for us yet...)
 

Chrisl77

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You might want to get a ss washer for the inside of your mash tun. It doesn't look like you have much material pinching that oring to the inside of your cooler.
 
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Cap'n Jewbeard

Cap'n Jewbeard

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So - everything was going swimmingly at first.

1) Strike water was at PERFECT temp and came up to temp quickly. Dough-in went swimmingly, and the grain was right at 122F. It looked pretty, too:



2) 1st decoction went pretty well. It took a little while to get to the target mash temp in the pot, but mostly because I am not used to the new pot and heating it on the stove vs. the propane burner. Once the boil started, it really darkened/caramelized very nicely, and it doesn't look like we had any scorching. I only pulled 4 qts, I think I probably should have pulled 5-6. This likely affected the temp issue below.


3) When we stirred in the 1st decoction, we (probably) didn't hit our temp. The goal was 152F, but the thermometer stubbornly refused to go above 140F. So adding 4 qt of boiling thick mash to about 11 qt of 122 F normal mash does not really bring it up to the desired temp. So most of the "saccharification rest" actually happened at 140F, we think, not 152 as hoped.

4) It was while we were stirring in this decoction that we found out the tube had fallen off. (So I edit my previous "J'accuse!" and direct it instead at this screen tube. J'accuse, screen tube!). While we panicked, we pulled the 2nd decoction (5 quarts this time), and got it boiling. Nice and caramelly, smelled great. Added it back in, and instead of getting to mash-out temps (168F), we FINALLY got to the 152 we had wanted. So we let it sit for 30 mins to do a "real" sacch. rest while we figured out how to sparge this thing.

5) We had hoped originally to be able to vorlauf/lauter like normal human beings, but of course that was impossible. We opened up the spigot and nothing came out; without the filter of the screen tube, it had filled up with grains. So we scooped all of the mash into a grain bag, on top of a colander, over the brew kettle. We had 2 gallons of "first runnings" this way, at gravity 1.080. Added 2 more gallons of sparge water by pouring it over the bag; this reduced the gravity to 1.060.



At this point we had a choice: keep sparging and almost certainly kill the OG, or call it a day and boil it down. Another 2 quarts brought the pre-volume boil to 4.5 gallons at 1.055.

6) In the kettle pre-boil, it looked like it had a LOT of sediment - but every AG I've done has looked like that, and the filter problem probably didn't do it any favors.



It's still boiling now, but the plan is to bring it back up to either 5 gallons or the right OG with cold water, and just hope for the best.

Also, my yeast starter isn't really making new bubbles anymore... but it was earlier today so maybe it's fine. Good god, this whole enterprise is doomed...
 

s4l

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Ouch. Hopefully it comes together. I might have missed it, but what's your target OG?
 
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Cap'n Jewbeard

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Well, yeast is pitched... it's maybe not so bad. I whirlpooled a bit while the cooling was finishing off, and it looks like it'll come out pretty clear. Post-boil gravity was 1.080 for (I'm estimating) 3 gallons. I added a gallon of cold water, which brought the OG to 1.055, which is pretty much bang exact for the style.

S4l, I was pretty much happy to get between 1.050 and 1.060, so it ended up being a slightly small batch of what should be really tasty beer. Time to put it in the cooler with an ice bottle or two so it ferments near 50F. The day is saved!

(Also we disassembled the valve, cleaned out the gunk, and will re-build it with the new bazooka tube and probably more plumber's tape. I think it's got all the right washers in it, but that's a subject for another time).

Edit: As a coda, this morning it's bubbling away happily. The carboy is sitting in a cooler with a wet towel on it and 2 frozen water bottles, which may help. I do have a Sanyo fridge for the lagering later on. I think we're gonna be OK.
 
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Cap'n Jewbeard

Cap'n Jewbeard

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New update:

This morning, the gravity was at 1.020, which is honestly 5 to 10 points higher than I was expecting. Perhaps it's not finished yet, I don't know.

More worryingly, I thought I tasted/smelled some banana esters when I sampled the bit I drew out for the gravity test. That may be a phantom (because I had a banana at breakfast shortly before), or it may be real if the ferment temp was a lot higher than I thought.

It's back in the cooler but all the ice has melted; I'm giving it a couple of days to do a "diacetyl" rest, but maybe that will take care of the banana issue too. I also want to see if it drops any further. If it doesn't, I'll rack it to secondary on Wednesday and get it into the fridge.
 

Yooper

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Thanks for the photos!

Once you do a couple of decoctions, you get a feel for them and it goes smoother each time. If I do one now, I generally go with a 133/149/156/mashout schedule, making the protein rest very short and the two different saccrification rests each 30 minutes.

It's hard to tell in the picture, but I wanted to make sure that your decoctions are mostly grain and little liquid. You want just enough liquid so that the grain won't scorch. That does two things- one, avoids pH issues and possible tannin extraction; and two, helps with bringing up the temperature to the next rest temperature better. I always pull more than I calculate that I need, and can always add it back when it cools a bit as to not get too warm in the mash. I hope that helps a bit!
 
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Cap'n Jewbeard

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Thanks for the wisdom, Yooper! Been a long time since we've (virtually) hung out!

I am interested in your mash temp schedule there. I was reading about protein rests the other day (Papazian, Homebrewer's Companion), where he says that a protein rest from 130-135F will give better head (eep...) and less haze. Have you found that to be the case vs. a 122F protein rest? When you say short, is that like... 10 minutes? How do you find the 2-step sacch rests, in terms of residual sweetness, extraction, etc?

I think that picture may actually have been from my 2nd decoction, which was a lot thinner. The first one was pretty thick, and started to look a bit oatmeal-y by the time we flamed off.

Great advice to pull more than expected! Will try that next time.
 

Yooper

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Thanks for the wisdom, Yooper! Been a long time since we've (virtually) hung out!

I am interested in your mash temp schedule there. I was reading about protein rests the other day (Papazian, Homebrewer's Companion), where he says that a protein rest from 130-135F will give better head (eep...) and less haze. Have you found that to be the case vs. a 122F protein rest? When you say short, is that like... 10 minutes? How do you find the 2-step sacch rests, in terms of residual sweetness, extraction, etc?

I think that picture may actually have been from my 2nd decoction, which was a lot thinner. The first one was pretty thick, and started to look a bit oatmeal-y by the time we flamed off.

Great advice to pull more than expected! Will try that next time.
Yes, I go with 131-133 because I found that at 122 I can lose some head retention and the 131 rest prevents that. (I primarily use fully modified malts, but even with slightly undermodified malt I have still been using the 133 rest).

As for "short"- I mash in and then immediately pull that decoction. Even doing it immediately means that the mash sits for 20 minutes or so because it takes that long to get to saccrification temperatures in the decoction, then I hold it for 10-15 minutes and then boil it and re-add.

When I do a decoction, especially one with two saccrification rests, I get better efficiency on the beer. I plan for 80% efficiency when doing a double or triple decoction and sometimes get over that.
 
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Cap'n Jewbeard

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That's great, thank you! I sense another lager coming on with this new and improved decoction schedule

As an update: transferred it to secondary/lagering fridge when it persisted at 1.020, with the fridge set initially at about 48-49F. (By the way, I didn't know it could go that high; next time I do a lager, I'll put the carboy in there from the beginning!) I put it in the fridge last night, and when I looked this afternoon it was bubbling again! I don't know if the yeast re-started or if it was just C02 coming out of suspension; I'm kind of hoping there was a new round of fermenting, because I really don't want to leave it at 1.020.

I'll bring it down a few degrees every other day for the next week or 10 days, until we're at 32, and then leave it there another 2-3 weeks until I need the fridge for the next brew.
 

TrickyDick

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Congrats on getting it done through the adversity. I think your mash tun is fine with that bazooka screen. False bottom in my experience with a insulated cooler is a disaster, because over time, the inner liner separates from the insulation material and when heated the bottom will bow upward, disrupting the seal on the false bottom giving you no filter, and you cannot forcibly flatten it out in the mash tun such as with a mash paddle. In fact is doubtful you'll realize that is the problem, it you will notice that you cannot get the runoff to clear of husks. It took be a year to figure out this was even happening. That is all avoided with the bazooka, also, are you sure the o ring goes on the inside? I think it might because of the double wall insulated cooler design. I had a leaker as well and it's no fun.
It can be easy to disrupt the screen with a mash paddle for sure. I couldn't see how it was connected but I'll bet a strong SS hose clamp will fix that issue.

I'm thinking about a DD mash for some lager beers later in the year, so this is inspirational! How did you scoop out the mash for the decoctions?

TD
 
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Cap'n Jewbeard

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I used a quart measuring cup thingy, and tried to let most of the liquid drain out before I dumped the thick mash into the kettle.

In hilarious-er news, this beer continues to be a conga-line of trauma and equipment failure. I've been struggling for days to get my lagering fridge in the mid-to-low 30s F; at that end of the temperature spectrum, it seems to only have 2 places it can go: 42, or 25. I came down to the fridge this evening to find a layer of slush on top of the beer and the airlock frozen solid.

Did I just kill my yeast? Will they recover and keep lager-eating?
 
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