If in doubt throw it out! Try Vanillacrystals instead. Long shelf life although that won't be a problem because you will be addicted to the taste. It is so much better than any extract.
Try Vanillacrystals.ca. The problem in your recipe is that your using extract which is alcohol based and evaporates when heated. Vanillacrystals are heat activated. They are all natural and the taste is addiciting:tongue out: