Homemade Kahlua requires 3 cups of sugar, 2 cups of water, 1 vanilla bean about 2 inches long, 8 tablespoons of instant coffee and 1 bottle of vodka. The total cooking time for the homemade Kahlua recipe offered on About.com is 70 minutes.
Combine the vanilla bean, sugar and water in a saucepan over medium heat. Boil the mixture until its volume is reduced by about half, which should take about 30 minutes. Turn off the heat and add the instant coffee to the saucepan. Stir the ingredients to combine them, then allow the mixture to cool.
Pour the mixture from the saucepan into a sealable bottle or jar, then add the vodka. Seal the container, shake it, and leave it in a cool, dark location for approximately 10 days. After the allotted time, strain the liquor through a piece of cheese cloth.
A simpler recipe for homemade Kahlua uses 6 cups of strong coffee, 3 teaspoons of vanilla extract, approximately 1 pound of brown sugar and about 17 ounces of vodka or rum. Brew the coffee. Dissolve the brown sugar into the hot coffee. Allow the coffee to cool to room temperature and stir in the vanilla extract and vodka or rum.