slow lager fermentation: let it ride, or pitch more yeast?

Yes, I underpitched my lager yeast.

It's got a nice krausen, and the airlock is going, but after 11 days its only 28% attenuated (to be fair nothing happened at all until around day 5 or so).

Should I add more yeast, or just see how far it goes on its own?

I pitched at 48-50F, and it's been there ever since.

Thanks.

I just had this same problem. I ended up warming mine up to the high 50s to get it going a little better, but it still took about 5-6 weeks to fully ferment. Its in the corny lagering now so i can't tell you how it turned out.

Let it Ride. Lager yeast works much more slowly than ale yeast, though yours is really working slowly. Bring it to room temp for about 3 days once you use up about 80% of the sugar to allow the yeast to break up the diacetyl. Then rack to the secondary and lager.

blaster said:

Let it Ride. Lager yeast works much more slowly than ale yeast, though yours is really working slowly. Bring it to room temp for about 3 days once you use up about 80% of the sugar to allow the yeast to break up the diacetyl. Then rack to the secondary and lager.

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That's exactly what I'd do.

If you've got fermentation now, the yeast have reproduced and are working. There would be no benefit at this point of pitching more yeast. You'll definitely need a diacetyl rest since the yeast must be pretty stressed. Then, after the diacetyl rest you can rack and lager.

Thanks everyone!

One other question - I'm assuming I should still plan on a full 6 week lagering period, even if the primary period takes much longer than the planned 2 weeks?

jigidyjim said:

Thanks everyone!

One other question - I'm assuming I should still plan on a full 6 week lagering period, even if the primary period takes much longer than the planned 2 weeks?

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Of course. Primary takes as long as it takes. That doesn't have anything to do with the lagering period, since the lagering takes place after the beer is fermented out.

blaster said:

Let it Ride. Lager yeast works much more slowly than ale yeast, though yours is really working slowly. Bring it to room temp for about 3 days once you use up about 80% of the sugar to allow the yeast to break up the diacetyl. Then rack to the secondary and lager.

Click to expand...

Quick numbers question. When you say 80% attenuated does that mean from the OG to the target FG or OG to 1.000?

In this case, it means 80% of the way to the target FG.

-a.

Checked in again today, day 17... down to 1.026 (62% of goal)... Hopefully it'll reach 80% (1.019) this weekend and I'll bring it up to room temp and it'll finish out around 1.012. Still crossing my fingers...

well, i'm sad to report that i finally got to try the one i had which took forever to ferment. The results were not positive. I'm going to let it sit in the keg for a while longer and see if it gets any better. Hopefully you have better luck with yours.