For me it takes between 2 and 3 hours. 3 days ago I took ds2 out for lunch at Taco Bell and had some nachos with medium sauce (not even that spicy!) and she had gas like you would not believe after her 3:00 feeding. It's getting better, though, b/c she wasn't cranky at all.
I don't eat spicy stuff often, though, so that's probably most of the problem.