Vanilla and Extracts
Vanilla extract is the most common form of vanilla used today. Vanilla extract and other extracts may be kept indefinitely if sealed airtight and kept in a cool, dark place. They need to be stored in air tight containers to prevent the volatile oils from escaping.
The suggested shelf storage for unopened extracts is 2 years. Opened extracts should be used in 12 months.
Source: Cupboard Approximate Storage Times, Kansas State University