Use a sharp, clean paring knife to split each vanilla bean in half, leave about ½ inch at each end intact.
1 ounce Vanilla beans in your favorite variety
Put your vanilla beans in a sterilized glass bottle or jar with a tight, secure lid, and cover with the alcohol.
1 cup Alcohol of your choice
Close jar or bottle and store in a cool, dry place out of direct sunlight for a bare minimum of 6-8 weeks, although 4-6 months is best for a more developed flavor. Give the bottle a shake every week or so.
If desired, repackage the vanilla extract in small glass bottles and label for gifting.
Notes
Scaling
Use the ratio of 1 ounce (by weight) of vanilla beans to 8 fluid ounces (1 cup) of alcohol to make as much extract as you like. For example, to make 1 cup of extract, use 1 ounce of beans and 1 cup alcohol. To make 1 quart of extract, use 4 ounces beans and 4 cups of alcohol.
Gifting
For gifting, feel free to add some of the spent vanilla bean into the bottles. It will continue to add flavor to the extract over time.
Storage
When stored in a dark, dry place at room temperature, the vanilla extract will keep more or less indefinitely. Be sure to keep the beans covered with alcohol and discard immediately if you notice any mold or if it starts to smell "off."