Frustrating lager fermentation. Warning: long boring story!

I need to vent a little and perhaps get some reassurance (hint, hint). Sorry in advance for the long post. Feel free to skip if your eyes start to glaze over or you get the "crap, not another 'is my beer OK' post" feeling.

I'm in the twelfth day of fermentation for my annual Oktoberfest, and it appears to have flatlined at ~1.020 or 1.019. OG was 1.058, pitched yeast slurry from a 2L starter plus an Activator pack (Wyeast 2633 Oktoberfest Lager Blend). Wort temperature at pitching was 44 deg. F. and I let it rise to 48 deg. F. over the course of ~16 hours. Fermentation was quick to start and continued strong, but started waning after 5 or 6 days.

SG hit 1.020 after 7 days. Started diacetyl rest by raising temperature controller to 61 deg. F.; however, it took 2 days to get to 59 deg. F. because of the very cool ambient basement temperature.

Anyway, after 5 days, the SG is only 1.019 (even that might be a wishful interpretation of the refractometer reading). The krausen is gone and the beer has cleared significantly. Not wanting to leave the beer at an elevated temperature for any longer, I have set the temperature controller to 56 deg. F. and will step it down to 51 deg. F. over the next day or so.

I'm concerned (read worrying) about the seemingly high SG and the fact that it was steady after raising the temperature for the diacetyl rest, presumably to boost yeast activity. My batch last year (nearly identical) went flawlessly and finished at 1.013 quickly.

This is only my fourth lager ever. Does this fermentation story fall within the normal lager experiences of other HBTers?

I'm holding some hope that the yeast are just a little sluggish and will eventually bring it down to the 1.013 range-- a sample I pulled tonight still seems pretty yeasty. I've swirled the fermenter for several days in a row, but to no avail. Maybe I should play some Pogues for the yeast to get them roused up?

Should I just shut up and not worry? Help me HBT, you're my only hope!

End boring fermentation story. Thanks for listening.

-Steve

the only thing I can think of is a difference in ingredients? The fermentation schedule seems fine.

What's the grain bill?

What was your mash schedule? Was it the same as your 1.013 batch? If so, are you sure you didn't overshoot the sacch. temp?

It's a partial mash of:

2 lbs. Vienna
0.5 lbs. Caramunich

Mash settled in at 150.8 deg. F. Was shooting for 154 deg. F. Added hot water over the course of ~25 minutes to raise it to 152.5 deg. F. Rested for another 37 minutes, for a total of ~62 minutes. My sparge water started at ~170 deg. F, but I didn't control it well and it fell to ~150 during the course of the sparge (still working out the whole mashing thing).

The rest of the fermentable bill was 6.3 lbs. of William's German Gold Liquid Extract (50% Moravian Pilsner, 50% Munich).

The 1.013 batch mash was very similar: settled at 150 deg. F., fiddled with it to bring it to 153 deg. F. and the same lack of control over the sparge water (I guess I didn't learn anything). Also, the 1.013 batch used 2 oz. more of the Caramunich.

It hit 1.021 after 7 days. Eight days later, it was at 1.015, at which point I raised the temperature controller to 62 deg. F. Eight days after that, it was at 1.013, then I crash cooled.

OK, so I guess I just kinda answered my question. My recollection was that last year's batch went quickly, but apparently it didn't. My assumption this year was that the gravity would go down quickly at the higher diacetyl rest temperature. Also, I started my rest last year at a much lower SG than this year. I think I'm a victim of my own flawed logic and assumptions.

So I guess I relax and wait. I'm just really psyched about this batch. If it's as good as last year's, then I'll finally post my first recipe on HBT.

Thanks for reading and caring!

-Steve

why is it that almost every time someone has a 'stuck' batch, it is at 1.020? does anyone know? this has happened to me once with a lager and i would love to hear a scientific response. by the way, OP, my lager came out fine, just a bit sweet.

blackwaterbrewer said:

why is it that almost every time someone has a 'stuck' batch, it is at 1.020? does anyone know? this has happened to me once with a lager and i would love to hear a scientific response. by the way, OP, my lager came out fine, just a bit sweet.

Click to expand...

Heh. After I thought I had a stuck fermentation, I started reading about the 1.020 curse here on HBT... didn't make me feel very good!

The samples I've been pulling taste very good-- just a tad sweet.

-Steve

OK, I'm officially calling it. Fermentation is done, FG = 1.018. SG hasn't budged in a week.

The sample I pulled tonight tastes good, just a tad sweet. Good thing I hopped it at the top end of the style guidelines!

I'll chalk this one up to perhaps too high of a mash temp (though my mash was pretty wonky-- undershot target temp then spent 25 minutes getting it back up to 154 deg. F.) and just the normal variation present in all fermentations.

Oh well, I bet once it's carbed it'll take the edge off the sweetness, though really, it's not that bad right now.

On to the next brew...

-Steve