Is windsor yeast super fast?

I made a porter on Saturday. I pitched my Windsor yeast at 6PM (wort temp was 62). there was no activity at 7AM Sunday. I went out and came home at 4 PM Sunday and there was activity in the airlock. Ambient temp was 67F. There was activity this morning (Monday) and now it’s 2:45PM and the activity has dramatically diminished, almost stopped. Could it be that I had a very aggressive fermentation and was not here for most of it? Could it be that the fermentation is done in 18 hours? OG was 1.064. Extract brew. Expected FG is 1.014.

Yes, it is very very fast. From pitch to finish is often about 36 hours. Unfortunately Windsor ale yeast is a very low attenuator. I doubt gravity will get much lower than about 1.024.

Oh, well that sucks. The package for the kit says 1.014. Are they misrepresenting or is that just their hope?

I wouldn’t sweat it.
I’ve only used Windsor a couple of times times, but it had no problem getting a recent 1.067 brew down to 1.012 (which was lower than the 1.016 that I was hoping for).
In any case, yes…the fermentation went very quickly and even though it attenuated more than I had planned, the beer turned out perfectly fine.

I could be wrong, they could be wrong… it’s all just a guess. Not to worry, though. If I’m right, you can still get the ABV that you wanted by throwing in an extra pound of cane sugar. If you’re going to do it, do it now and give it another couple days to ferment out.