Using a sharp knife, carefully slit the vanilla beans down the middle. If necessary, cut the vanilla beans into smaller pieces so they fit into your jar or bottle.
Place the vanilla beans into a clean glass jar or bottle.
Pour 1 cup of vodka, bourbon, brandy, or rum over the vanilla beans.
Make sure the vanilla beans are completely submerged. Add a little more alcohol if necessary.
Seal the jar or bottle tightly.
Store the vanilla at room temperature away from direct sunlight.
Shake the bottle about once a week.
Allow the vanilla to infuse for at least 6 months for the best flavor. The longer it sits, the darker and more flavorful it will become.