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Old 10-05-2011, 07:32 AM   #1
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Default First lager, 2x5g carboy's ... different gravities, when to do a diacetyl rest?

I brewed my first lager, a doppelbock which came in at 1.080 OG. I pitched it at 55f on 9/9/11 and it has stayed at 55f. I underpitched fairly heavily ... which was unavoidable, due to time restrictions. My starter was 4L, I only pitched one vial of WLP833, and shook the starter every time I walked by. Mash temp was fairly high at 157f.

Gravity readings as of today are: 1.032 and 1.024 for the two different carboys, and I am wondering if/when I should do a diacetyl rest. I was not able to taste the samples (currently in a different country than the beer) so I dont know if you can taste diacetyl in it, but I am assuming you can.

Should I do a diacetyl rest? At what temp? Do I wait for the 1.032 carboy to drop more before doing it?

Again, this is my first lager, so I am fairly clueless...

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Old 10-05-2011, 08:52 AM   #2
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No offense dude, but you really should have read up a lot more before even attempting a lager. They take a lot more time and effort.
Read this http://www.braukaiser.com/wiki/index...st_propagation

First off as you said you severly underpitched. Mr. Malty says for 5 gallons wort at 1.080 you'd need 2 vials (at 75% vitality) and 6.6L of starter using intermittent shaking. That's just for one batch. Did you split your 4L between your two batches? Either way, the yeast would be stressed and produce more off flavors and possibly under-attenuate which sounds like your problem.
Generally for a D-rest you want to raise the temp up when it's about 3/4 of the way through fermentation. That's why people like to do a satellite sample with a fast fermentation test for lagers. But if since your beer's been going for a month now its probably too late for a d-rest anyways. You do the D-rest while the yeast is still active. Also you only need to do it if you taste diacetyl.

The style guidelines say a doppelbock's FG should be between 1.016-1.024. So your second one is within range but I would try to get the other one down by adding a proper yeast starter at high krausen. If they both have diacetyl you might want to do that for both.

For reference, my doppelbock was OG: 1.085 FG: 1.020; cold pitched at 42F, slowly warmed to 48F over 2 days, fermented for about 3 weeks, d-rest wasn't needed (but if so I would have warmed to 65F for 2 days when SG~1.027), racked to secondary, then I lagered at 35F for 3 months

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Old 10-05-2011, 11:20 AM   #3
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Meh, brewing a lager isn't really a whole lot more difficult. You have to pitch more yeast, you need a way of controlling lower than ale temperatures, and you typically do a diacetyl rest when fermentation is about 3/4 of the way thru and you should lager the beer for about a month(but this can be done with any beer).

I think you missed your opportunity to do a diacetyl rest.
I think you under pitched.
I think you need to start your lagering now.
I think you made beer.
I think it will taste good.
I think if you correct your mistakes, your next lager will be better.

That's just my humble opinion

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Revvy>>You shouldn't worry about ANYTHING, you didn't hurt the yeast, they know what they need to do, they want to eat all that sugar they are swimming around in. They want to pee alcohol and fart co2, it's their nature.

Bobby_M>>I flood the keg with CO2 for one minute with the lid off, rack the beer in to the bottom gently, seal it, flood it, vent it. If there's still O2 in there after that, F it.

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Old 10-05-2011, 12:44 PM   #4
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If the 1.032 beer is still dropping, that's a good thing. I'd wait and do the diacetyl rest when activity slows quite a bit. Usually, I do the diacetyl rest when the beer is 75% of the way done, so usually about 1.020 or so. But if the activity has greatly slowed, you could do it now.

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Old 10-05-2011, 03:06 PM   #5
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Quote:
Originally Posted by Yooper View Post
If the 1.032 beer is still dropping, that's a good thing. I'd wait and do the diacetyl rest when activity slows quite a bit. Usually, I do the diacetyl rest when the beer is 75% of the way done, so usually about 1.020 or so. But if the activity has greatly slowed, you could do it now.
Quote:
Originally Posted by jetmac View Post
Meh, brewing a lager isn't really a whole lot more difficult. You have to pitch more yeast, you need a way of controlling lower than ale temperatures, and you typically do a diacetyl rest when fermentation is about 3/4 of the way thru and you should lager the beer for about a month(but this can be done with any beer).

I think you missed your opportunity to do a diacetyl rest.
I think you under pitched.
I think you need to start your lagering now.
I think you made beer.
I think it will taste good.
I think if you correct your mistakes, your next lager will be better.

That's just my humble opinion

Or maybe you could start the diacetyl rest now. Sorry, my bad, after calculating 65-75% of 1.080 t turns out you're right about where you need to be for a diacetyl rest. Diacetyle rest temp should be about 65-68F for a couple days
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Revvy>>You shouldn't worry about ANYTHING, you didn't hurt the yeast, they know what they need to do, they want to eat all that sugar they are swimming around in. They want to pee alcohol and fart co2, it's their nature.

Bobby_M>>I flood the keg with CO2 for one minute with the lid off, rack the beer in to the bottom gently, seal it, flood it, vent it. If there's still O2 in there after that, F it.

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Old 10-05-2011, 07:58 PM   #6
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Alright, I guess I could have expected the berating studmonk3y, and thanks to you all with helpful input . I knew I was under pitching, and based on my short R&R timeline and my procrastination, I didn't have a choice ... I figured it would just be an estery lager, and I used the RDWHAHB method of lager brewing.

The readings were taken Tuesday evening (Texas time), and I am going to have my wife take another reading on saturday or sunday. If the 1.032 beer hasn't fallen at all, I'm going to have her brew up another starter (4L off one vail?) and pitch it to both beers. If it has fallen a point or two, and diacetyl or acetaldehyde is detected I'll have her raise it to like 68, which should help it finish out to its FG I am assuming.

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