The yeast is a London Ale Yeast. I've used it quite a few times and never seen anything like this on the beer. If you want, I can snap a photo.
I was also thinking it might be some non-sugar compoind from the maple tree that got orphaned during fermentation.
I agree that I would expect noticeable off-flavors, but I still have a hard time believing that a second fermentation pushed the FG a full 5 gravity points lower than the first fermentation...
And I thought sulfites were only used for stabilizing wine by stopping oxidation. In fact, in this...
Hey guys,
So I brewed my first maple syrup beer last month. A buddy working on a syrup farm in the northeast shipped some grade C stuff (darker than anything in stores) and I added it after primary (because I wanted to minimize the amount of maple syrup flavor lost in fermentation bubbling)...
I've read these forums for a couple years, and finally I get to contribute something...
I have actually been debating this topic with a buddy recently, so I did some calculations. With the following assumptions:
5-gallon brew
SG 1.065
75% attenuation
20% heat loss from expelled CO2...