Does anyone know what's the shelf life on the Nielsen-Massey vanilla?
Honestly, it has such a high alcohol content, I doubt it has a recommended shelf life. Bacterial activity, light, and air are the elements that affect shelf life. It may lose some of its potency, depending on how it's stored, but I doubt it will go bad.
Vanilla extract does not expire, but it may be more potent than usual if some of the alcohol has evaporated off.