Should brussel sprouts ever taste like chemicals? So I got a bunch of what I thought were locally grown organic brussel sprouts from the local coop the other day.  They came in an unlabeled zip lock bag, which usually means small local farm.  I cooked them with some butter and oregano. I under cooked them a little bit, but I usually prefer them that way.  When I ate them, I began to notice that they had a mild chemical taste.  It burned in my nose and the back of my mouth a little bit.  It was a sensation very similar to the one caused by ammonia or bleach fumes.  I hadn't washed them as thoroughly as I perhaps should have (there were black spots on them I hadn't noticed before, but the cooking brought them out). 

Do brussel sprouts naturally have some ammonia, or something similar I might have been tasting (and why don't I remember tasting it when I've eaten them in the past)?  Did I just down some lovely pesticides and herbicides?  Could those black spots have been a fungus that was producing something unpleasant?
Brussels sprouts are in the brassica family, so you can get that family of strong cabbagey/spicey/sulfurous flavors and aromas. You probably know what that tastes like though, so I'm assuming it wasn't that. I've seen those black spots plenty of times, and I generally trim them, but I don't think they would be likely to give off a strong aroma. Once I had a situation like this where a vegetable tasted of kerosene, which I assumed was a cross-contamination and dumped it. That's what I would recommend if this ever occurs again. If in doubt, throw it out.