Pure vanilla extract calls for just two ingredients: alcohol for extraction and vanilla beans. As you can imagine, it has the shelf life of basically forever, since its ingredients are pretty shelf-stable. With so many cork-topped vials of DIY vanilla extract on the web, there's also some misinformation about how and where you should store homemade vanilla extract for gift giving.
Store it in an airtight jar.
The sort of disappointing news is that you shouldn't gift your homemade vanilla extract in cork-topped bottles. They are prone to evaporation and, because they are loosely sealed, they can let in unwanted scents on nearby items like vinegar, liquid smoke, and fish sauce. Instead, opt for a swing-top or screw-top bottle that can be tightly sealed between uses. Bonus points if the bottle is amber or cobalt glass to protect the vanilla extract inside.
Store it in a cool, dark place.
For long-term storage, keep the vanilla extract in a cool, dark place like your pantry. Heat and light can cause evaporation and cause the extract to turn cloudy. Slightly cloudy- or muddy-looking extract is still fine to use as long as it passes the smell test.
For gift giving, be sure to note that the extract should be stored in the jar in a cool, dark place and note the date it was made in case it gets pushed to the back of someone's pantry before they have chance to use it.
Get a recipe: How To Make Vanilla Extract at Home