I’ll never forget the first time I encountered solvent character in my homebrew. It was one of my first attempts at high-gravity beer (a Belgian dark strong ale, specifically), and I had been told that an elevated temperature was key to achieving the necessary attenuation. I (under) pitched Wyeast 1762 Belgian Abbey II into 1.085 wort at 72°F (22°C) and let it go: I’m pretty sure fermentation topped out well north of 80°F (27°C).
I succeeded in achieving excellent attenuation, but I paid a dear price for it. The resulting beer had a hot, burning character that in very small amounts might have actually been pleasant. Instead, I had made five gallons of paint thinner.
Solvent character is almost always the result of fermenting too hot. Generally speaking, the hotter the fermentation, the hotter the beer. High temperatures crank yeast metabolism into high gear, but in doing so, our fungal friends create more of what are known as acetate esters. Such esters are members of the same family as many of your favorite industrial chemicals, including paint thinner, nail polish remover, varnish, spot remover, turpentine, epoxy, and super glue.