Over-attenuation yeast?

My last couple batches have hit significantly lower FG than the recipe (and yeast strain) predicted. I know there are lots of variables, but I wonder if I'm just missing something obvious.

I made a ESB with WLP023 and it hit about 83% for a FG of 1.009, compared to the 1.015 estimate.

I also made an amber with some washed 1056 and that one hit 85% for a FG of 1.009, compared that its estimate of 1.013.

1.009 doesn't seem unbearably dry to me, but it is pretty low. I ferment in an area of my basement where it's a steady 66°F. The ESB got a half a vial for a 2.5G batch and the amber got about 80% of the amount of slurry recommended by MrMalty (so I estimate that both with slightly under-pitched). Both batches took off like a rocket.

None of my beers have been bad, but every batch has had over-achieving yeast or something. Or my hydrometer is out of whack. But the last 2 or 3 batches have been significantly under the estimated FG.

Any thoughts?

All grain or extract?

MalFet said:

All grain or extract?

Click to expand...

One of each. The half batch of ESB was AG and the amber was extract.

I'd double check your hydrometer. Those can be up to .006 out of whack.

It seems a bit odd for the extract batch in particular. What temperature did you mash at for the ESB?

Are you spending time talking to the yeast? I've heard reading a bedtime story to your fermenting beer helps attenuation. Otherwise, you might just be lucky. Time to brew a Saison?

1056 can chew the crap out of sugars like that, but still a little surprising given it was extract. Maybe too low a mash temp on the AG?