Mistake: Mega esters from Wyeast 1968

[CanaBeer]

I brewed a nice toasty ESB around April 10. The grain bill was something like:

10 gal

M.O. 90%
Crystal 40 5%
Toasted 5%

Bittering hops
2 oz Goldings @ 10 min.

30 IBU
OG 1.042

I had some washed Wyeast 1968 in the fridge that I had been using regularly with fantastic results. The thing is, the last washing was four months ago, before Christmas. I made my normal starter of 100g DME to 1L water, and gave the yeast three days on it. It was definitely fermenting when I pitched to my carboys, but that's where things went off the rails.

1968 usually explodes and finishes in a week or less. This time fermentation gently increased over the first week, and was still foamy on top at week two. After three weeks the gravity was still at 1.020, with airlock activity and bubbles on top. The sample smelled like dried apricots to the extreme. The taste was nice and smooth, but the aroma was hard to get past. I know 1968 is known to be estery, but this was ridiculous, and orders of magnitude past any previous experience with it.

I'm gonna let it keep going till it doesn't want to go anymore. I'll see what my filtration and carbing do to it. New name: Toast and Jam Bitter (sheesh).

Any advice out there for what I did wrong? Did I underpitch? Is four months too long for washed yeast viability?

Cheers Everyone!

 

[Golddiggie]

Fermentation temperatures???

Get a stirplate if you're going to make smaller starters. They'll finish faster too. I have yet to need tk make one more than 3L that way.

 

[LLBeanJ]

Majorly under-pitched. A 1L starter is not nearly enough for 10 gals with old yeast even at 1.042. I don't think even a fresh smack pack would be enough to get you there with just a 1L starter.

Next time, use mrmalty.com or yeastcalc.com and build up the proper cell count.

 

[cosmo]

What I do with my washed yeast that is more than a month or so old is step it up on a stir plate. I start with 500ml of wort. That usually takes 24-36 hrs. I then chill and decant. Now the yeast seems to be woken up. I add 1 liter of wort and let it go another 12-18 hrs on the stir plate. That's all it usually needs to complete. I then chill for a couple days and decant just before pitching. The two-step process ensures that the yeast is in excellent shape to pitch, even if it has been sitting in the fridge for several months.

 

[CanaBeer]

I ferment at 68F.

Sounds like I did indeed majorly underpitch, according to some of you guys. Lesson learned.