Thanks for that, I have some that are a year past date and they are fine, I expect they will stay usable for well past the use by date. I think on our cupboards and things like vanilla, lemon, orange etc, that we use for baking. Who even checks the dates on those when they bake their holiday goodies?
They just get weaker over time. I use orange extract when I make pizzelles, and after several years, I can tell the difference between an older bottle and a new bottle. Most of the pungent orange smell is gone after a few years.