Problems with washed yeast ???

[kjung]

I have a batch of washed Cry Havoc that I used to make two AG batches of Pale Ale.
The first batch I made with Marris Otter, I used yeast nutrient in the starter, and had a target FG of 1.017. It finished at 1.026 !
The other batch, the exact same ale, only with 2-Row pale malt (and I forgot the yeast nutrient in the starter), also had a target FG of 1.017, and it wound up finishing at 1.020. Granted, that's only 3 points off, but I've never finished THIS far off before, and I'm equally amazed at the discrepancy between the two FG's.
My OG's were only one and two points off.
Does anyone have ANY idea how/why this happened ???

 

[ArcaneXor]

I am not familiar with that particular yeast, but washing, if done properly, shouldn't affect fermentation properties until several generations down the road.

How large were your starters, what was your fermentation temperature profile, and how did you attempt to fix the stalled fermentation?

 

[kjung]

I am not familiar with that particular yeast, but washing, if done properly, shouldn't affect fermentation properties until several generations down the road.

How large were your starters, what was your fermentation temperature profile, and how did you attempt to fix the stalled fermentation?

Starters were 1000ml, temp was within range, and wasn't much that I COULD do, that I know of, other than shake the fermenters, which didn't do much, if anything.

 

[ArcaneXor]

With washed and frozen yeast, I like to step up my starters from about 200 mL to 2000mL. I also (no matter what yeast I use) gradually ramp up my fermentation temperatures after ~3 days after fermentation starts to ensure maximum attenuation. I.e., as a random example, I'll start my Koelsch beers around 63 degress F and hold it there for a few days, before letting it rise into the mid-70s by 1-2 degrees per day.

Just a couple of suggestions that may help for future batches.