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-   -   2nd AG: Attenuation too high, again... (http://www.homebrewtalk.com/f36/2nd-ag-attenuation-too-high-again-20471/)

Evan! 01-25-2007 01:18 PM

2nd AG: Attenuation too high, again...
 
So I'm not sure what I'm doing wrong here. My pilsner was my first real lager, and my second AG batch. I used mostly pilsner malt, with half a pound each of aromatic and carapils thrown in too. My first AG batch's FG was too low---1.011---so for this batch, I took the advice of the forum crew and switched from a stepped mash to an infusion mash. However, because this was a pilsner, I wanted to mash towards the lower end of the temp range. I think my average mash temp was about 153f.

As I said, efficiency was good, and my OG was 1.054 or so.

I pitched a large (1000mL) starter of Wyeast Bohemian Lager yeast into 60f wort and waited overnight (at about 60f) for signs of fermentation, then dropped the temp to the low 50's, which is right in the middle of the range for the Bohemian.

As I noted yesterday, I was expecting a lager to take awhile to ferment, so I was surprised when the airlock activity subsided after 5 days, and the krausen fell. I was concerned, so I took an SG reading last night, expecting the fermentation to be perhaps 2/3 finished. Given the listed attenuation of this yeast, I was expecting a final final grav of 1.014 or so. My plan was, as soon as it hit 2/3 of the listed attenuation, I would bring the temps up for a diacetyl rest.

You can imagine my surprise/frustration when my hydro read 1.012. 5 days post-pitching, and this "lager" has surpassed the listed attenuation. WTF!? So, not only did I miss my chance for a D-rest, but I'm worried that it's finished so early, and is so dry. I expected the carapils to help out with unfermentables, but I don't see them anywhere. What's going on? I'm 0/2 on AG batches, it seems, and I don't really get why. I've tried stepped mashing, infusion mashing, and they still attenuate too much.

Not only that, but to add insult to injury, my other batch that I brewed alongside the Pilsner, a PM Imperial IPA that I also infusion-mashed, had horribly efficiency (I had to do a supplementary boil with extract and add it post-pitching), and its attenuation (this is pacman!) looks really bad. I took a hydro reading from it last night, and it's around 1.030. Blagh! Bastard! If I wasn't so bloody careful in labeling the starter jugs, I could have sworn that I got my yeasts mixed up.

Damnit. :mad: I think I may just go back to PM.

clayof2day 01-25-2007 02:23 PM

Well, the good news is that the lager yeast will clean up diacetyl in the lagering phase, it just takes a lot longer than it does at warmer temps. More good news, if you don't taste the diacetyl, the yeast already cleaned up after themselves and you should be fine. Also, keep in mind that the % attenuations listed by yeast labs are ESTIMATES, and often the are gernerously low based on the fact that not all people will do starters or aerate their wort well. Things like proper pitch rate and aeration (which we know you do well with an aquarium pumpt) all create an environment better for yeast health and growth. I think that it is pretty common to get a little better attenuation than listed on most yeast strains if you take care of them properly. I don't think 1.012 sounds all that unreasonable for a FG in a Bohemian Pilsner, I think you will have yourself a damn fine beer. I don't think most of us worry too much about missing our FG by a point or two as there are SO many variable in AG that will play into it. If you are really concerned that much about consistancy and predictability it maybe better to stick with PM as extracts are very consistent.

Best of luck, I hope you cheer up, at the very least your pilsner now has a slightly higher ABV!!

Matt

cweston 01-25-2007 02:33 PM

I agree that 1.012 doesn't seem unreasonable at all.

Maybe a dumb suggestion that you thought of a long time ago, but have you checked your hydrometer in 60-degree water?

Also, could you be losing a lot of heat very quickly in your mashtun? That would drop the mash temp during the more critical first period of conversion and leave you with a more fermentable wort than you are shooting for.

the_bird 01-25-2007 02:47 PM

Evan, are you just gloating? Let me guess, your dick's too big, too? ;)

zoebisch01 01-25-2007 03:51 PM

Quote:

Originally Posted by the_bird
Evan, are you just gloating? Let me guess, your dick's too big, too? ;)


Nah, I don't think that's it. He's an architect. The numbers aren't adding up. Look at his brewspace. You get the picture :D

Evan rdwhahb! Just roll with it m8. You can't expect to hit it all 100% of the time anyways and I think going back would not bring you satisfaction. Yeast is wierd sometimes and they aren't as predictable as we want them on occasion. Double check you are not off in Temperature when taking those readings either.

"Ya done a good jeeearrrrrrrrrrraaaaahhhhrrrrrbbbbbb!"

Kaiser 01-25-2007 03:56 PM

As the others already pointed out, an FG of 1.010 - 1.012 is about perfect for a Pilsner. I generally shoot for 1.010 for my Pilsner and Helles and 1.012 for a Maerzen.

As for the FG, I highly recommend that you do a fast ferment test when you brew lagers. I always make one and the few times I didn't I really missed having the information that I gain from it.

A fast ferment test is overpitching a small sample of your wort and fermenting it warm (room temp). This is best done in your starter flask and takes only a few days. Because of the overpitching and higher temp, the yeast will consume all fermentable sugars and once the fermentation is done you can measure the FG you got and determine the limit of attenuation. This is the maximum attenuation that you can get from the wort you made and it doesn't depend on the strain of yeast (but it depends on ale v.s. lager yeast). The final attenuation of your beer (after lagering) should be only 0.5 - 1.5 % less than the limit of attenuation you got from the FFT. The less the difference the drier the beer will be since there will be less fermentable sugars left. Fermentable sugars are sweeter than unfermentable. Because of flocculation characteristic, nutrient depletion and other factors the yeast doesn't usually reach the limit of attenuation in the proper fermentation and this difference is an important charachteristic of the final beer.

Kai

Evan! 01-25-2007 04:25 PM

Quote:

Originally Posted by the_bird
Evan, are you just gloating? Let me guess, your dick's too big, too? ;)

No, really, I was seriously pissed off when I saw that hydro reading. Chalk it up to lack of lager experience, but when things go much differently than people tell me they should (even if your FG is about right), I tend to get concerned. Yeah, maybe this beer will turn out fine...but we'll see. I didn't taste any diacetyl in the sample, so maybe that will be a non-issue. Keeping my fingers crossed. And thanks to all of you for telling me to just relax. I needed it. :mug: I can take one batch being screwed up, but when both of them are...it's a little overwhelming. But, then, perhaps neither will be screwed up.

Anyway, I'm just wondering whether every single AG batch I do will ferment out way past the listed attenuation and end up around 1.010. I'm 2 for 2 so far...and while good attenuation is not necessarily a bad thing, I can tell you this---that Brune Abbey was way too dry, almost to the point of tasting watered down. I wouldn't consider that "gloating", brother.

And then there's the case of the IIPA. I mashed it side-by-side with the pilsner, at the same time, with the same constants, the same temps, all that noise...and somehow, my efficiency was great on the pilsner, but awful on the IIPA. Who knows what the deal is, but something went awry somewhere...and now, to see that one batch attenuated too much (kinda), while the other one didn't attenuate enough. Wacko. But I'll survive. I will say this: that IIPA is nice and bitter, and the hops are showing brilliantly. Hopefully it'll drop another 5-10 points between now and bottling. 1.020 would be perfect.

Then again...maybe I screwed up the hydro reading in the first place, and my efficiency wasn't that bad, and the supplementary boil that I did took the OG way high, which is why it's finishing high. Hehe. Who knows. Keep your fingers crossed for me...:drunk:

Evan! 01-25-2007 04:31 PM

Quote:

Originally Posted by cweston
I agree that 1.012 doesn't seem unreasonable at all.

Maybe a dumb suggestion that you thought of a long time ago, but have you checked your hydrometer in 60-degree water?

Also, could you be losing a lot of heat very quickly in your mashtun? That would drop the mash temp during the more critical first period of conversion and leave you with a more fermentable wort than you are shooting for.

Both good points. I'm using kettles to mash in, and just adding heat when they drop...so you may be right on that one.

Haven't calibrated the hydro in awhile either. Anyone know the standard readings adjustments for temps? What is the baseline temp where it should be accurate?

That's one thing that I never do...stupidly...I never make adjustments for temperature when I take hydro readings. I guess it's because I normally am just looking for a ballpark figure.

zoebisch01 01-25-2007 04:40 PM

Quote:

Originally Posted by Evan!
Both good points. I'm using kettles to mash in, and just adding heat when they drop...so you may be right on that one.

Haven't calibrated the hydro in awhile either. Anyone know the standard readings adjustments for temps? What is the baseline temp where it should be accurate?

That's one thing that I never do...stupidly...I never make adjustments for temperature when I take hydro readings. I guess it's because I normally am just looking for a ballpark figure.


The best thing I have found for this:

http://hbd.org/cgi-bin/recipator/brew/widgets/hc0.html

Although I tend to be a little shy about using the corrections above 110 or something. I have no way to prove this other than gut instinct, fwiw. :D

JohnnyK68 01-25-2007 05:39 PM

Quote:

Originally Posted by the_bird
Evan, are you just gloating? Let me guess, your dick's too big, too? ;)

That is some funny shyt right there....LMFAO!


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