Yeah, I had a 1.100 RIS that was at 1.022 three days later, and that's where it was after a couple weeks as well. Definitely possible to ferment big beers quickly. Of course, I also had a tripel that did indeed take a couple weeks to get to FG. Every time I get to thinking I know how a fermentation will go, the yeast decide to show me I don't really know anything.
Funny you mention that. I have a 1.076 Porter that going really slow. I don't get it. Maybe just some tired yeast.
