Slow Fermentation

[Brody]

My Pilsner is now at day 5.5 since pitch, I skimmed off a thick krausen, took a gravity reading of the main batch as well as the FFT.

The FFT showed 1.012 (so 75% attenuation, if my math is right? 1.048 original wort) which seems in line with the high end of 2000 (what I assume the brewpubs 'Czechvar' yeast is). So I'm assuming the mash went well.

However the main batch is still sitting at 1.040 (16% attenuation?). I've never read a lager this early but usually at this point my ales have about reached FG. Any need to panic ? Not sure if lagers usually cook this slow (kegerator was set to 48f, just bumped it to 50f).

[Bryan R]

Yea thats too low. I hit fg of a batch I brewed on friday, today. It was a 1.048 helles with 838. Bump that up to 52ish.

I don't exactly recall your step times, but your FFT is a little higher than it should be. This is going to put you at ~1.014fg on the helles and thats not enough. You should really see 1.008 on the FFT, 1.009-10 on the main. 60 minutes at 62 should get you there.

[Brody]

Perhaps I'll look into a higher attenuating strain too if a longer low rest doesn't help. I'll see how the rest of the fermentation shakes out, weird since I've had no problem with this strain before.

[Techbrau]

Do your FFT on a stir plate, or shake it frequently in order to get the yeast to ferment all of the fermentable sugar. That's the only way to know if your high finishing gravity is due to the mash or the yeast.

[Brody]

Didn't use a stirplate but shook it a good bit initially, I'll read it again in a couple days. Krausens reforming strong again in the main batch.

[Roachbrau]

[Brody]

Makes sense, gave it some more shaking and will re read after a bit.

[Brody]

Another update:

Skimmed the Krausen again today and took more readings.

FFT is still at 1.012 (75% attenuation) after more rousing and a few more days. So definitely going to increase the low rest next batch. The sample tasted surprisingly clean given a ferment at 70f or so and was clearer than I expected. Very smooth - Maybe a bit lacking in body but it was extremely over pitched.

The main batch is still chugging along and now down to 1.030 (so 37.5% about a week on). Will probably raise the temp once I hit 50% unless that's unadvisable.

[Weizenberg]

How much oxygen did you use?

[Brody]

I don't have a meter or O2 setup so Im not sure.

Basically I get O2 into solution by vigorously transferring the wort between two vessels and then shaking the hell out of the keg for a couple minutes making sure to produce a lot of the white foam.

Ended up taking 9 days to hit 50% attenuation (using slurry from a brewery). Never had any issues with ales with my O2 method but could see that it may have some value with light lagers.