My salsa's taste ok when eating, but the following morning there is a dreadful after-taste in our mouths. This doesn't occur after eating salsa at a restaurant.
Recipe: red onion, 1 clove garlic, tomatoes, basil, chille (seeds removed), olive oil.
I've tried soaking the chopped onion in milk which slightly improves things but a long way from a cure. I've tried different types of onion & adding lemon or lime which hasn't worked either. Been experimenting for over 10 years and still a poor salsa maker!