Yesterday I was infusing garlic olive oil with lemon slices for a creamy pasta sauce. I have done this in the past - I usually cut thin lemon slices and toss them into hot oil until they brown a bit. This time, though, it made the entire dish taste really, really bitter. It tasted a bit like the lemon peel itself, but it was very strong and infused the whole dish. I have never had this problem before. Any ideas on what the issue would be? (If it makes a difference, this was a spontaneous dinner and I grabbed a lemon from the corner store, so it probably wasn't great quality. I did rinse it, but briefly. The other things in the sauce were onions, mushrooms, creme fraiche, and oregano).