Wyeast 1968 London ESB: Quick fermentation?

I brewed a London ESB on Friday, aerated with my aeration kit very thoroughly, pitched my starter around 7pm. When I woke up Saturday morning, fermentation was vigorous. It continued this way through the weekend. 1" krausen, and a very turbulent wort---you could see it swirling around and a lot of big chunks were constantly falling. Airlock activity was extremely frenzied. That was the story when I went to sleep last night.

Woke up with morning (Monday), and the krausen had completely fallen. Airlock activity has slowed down considerably. My fermentation temps are between 68 and 70, consistently.

I've had krausen fall this quickly before, so I'm not worried so much...but I've never used this particular yeast. Looking at Wyeast's explanation, it sounds pretty odd:

Unique properties: This extremely flocculant yeast produces distinctly malty beers. Attenuation levels are typically less than most other yeast strains making a slightly sweeter finish. Ales produced with this strain tend to be fairly fruity. Fruitiness increased with higher fermentation temperatures 70-74º F, (21-23º C). Diacetyl production is noticeable and a thorough rest; 50-70º F, (10-21º C) is necessary. Yeast traps trub easily and autolysis is possible. A very good cask conditioned ale strain due to thorough flocculation characteristics. Beers become readily bright within days. Brilliant beers easily achieved without any filtration. Alcohol tolerance approximately 9% ABV. Flocculation - high; apparent attenuation 67-71%. (64-72° F, 18-22° C)

Click to expand...

I also read somewhere else (can't remember where) that this strain is so flocculant that re-oxygenation during fermentation is recommended. Has anyone ever done this? I'm wondering if I should shove my aerator into the wort at this point. Normally, I'd RDWHAHB, but since I actually read that you were supposed to re-aerate, I'm wondering if that's the reason why fermentation activity has dropped off so soon.

Also, I've never done a diacetyl rest, as is recommended in the above description---how would I go about that?

Any other suggestions for my situation?

Do NOT add additional oxygen. What you read was that the yeast sometimes needs to be roused off the bottom to finish fermentation.

The way to get an ale strain to absorbe diacytle is by letting the beer sit on the yeast. I usually primary this strain for 10-14 days before racking. However...I tend to do this with all ale strains.

No, actually, they said that it needed to be reoxygenated, using an aeration or oxygenation kit. Needless to say, I'm skeptical.

Regardless, there's no need for it. I finally checked my gravity this morning, just to make sure I didn't have a stuck fermentation. Not only is my fermentation not stuck, I've actually surpassed the listed attenuation range! Went from 1.059 to 1.015 in, basically, 2 or 3 days. That's 74.5% attenuation, and Wyeast says the expected range is only 67-71%! That's some fast yeast

Given that the fermentation is basically done (since I've already surpassed the listed attenuation range, I doubt it'll do much more) within 3 days, how much longer should I leave it in the primary in order for the diacetyl rest to complete? I have no problem letting it sit for 7 or even 10 days, but I'm just wondering how long is necessary...I'm not used to achieving 74% in 3 days, that's all.

Also, tasted it when I took the readings, absolutely delicious! And Wyeast was right when they said that it produces brilliant beers---it's already clearer than many of my previous batches, even after months of bottle conditioning!

Also, when I was formulating this recipe, alot of people said that I shouldn't use the London ESB strain on a London ESB, because it's too fruity. Even Wyeast conceded that point in their description. However, fortunately, it didn't turn out extraordinarily fruity...at least not yet. I did keep my fermentation temps down below 70, though. Either way, this is set to be a great ESB. Gonna dryhop with EKG in secondary.

Evan:

I am using this yeast currently in about 4 brews and have made a similar observation that this yeast ferments unlike other yeast strains. It tends to sit longer before CO2 evolution from the fermenter and then finishes quickly. I have not added any air per your post, but I have also had low FG indicating complete fermentation. I don't think the aeration is necessary. The beers I have racked so far have a fairly fruity character much like English style beers.

Dr Malt