To make homemade Kahlua, start by brewing a very strong pot of coffee; light brown sugar, vanilla extract and 190 proof Clear Springs or Everclear are additional ingredients. Cooks.com recommends using chocolate-flavored coffee.
In a large pot or sauce pan, boil 12 cups of coffee and slowly add in 2 pounds of light brown sugar. Be sure to stir the mixture constantly. Next, remove the pan from heat and allow it to cool to room temperature or add 1 cup of ice for quicker cooling. Once the liquid is cool, add 4 to 6 tablespoons of vanilla extract and 1 bottle of 190 proof Clear Springs or Everclear. Store the mixture in the refrigerator and add it to vodka to make a variety of coffee-flavored alcoholic beverages.
Another recipe for homemade Kahlua, from Food.com, combines 1 1/2 cups dark brown sugar, 1 1/2 cups granulated sugar and 2 cups water into a small sauce pan. Cook for about 10 to 15 minutes until all of the sugar is dissolved. Remove from heat, add 1/2 cup instant coffee and allow the liquid to completely cool. Once cooled, add 1 3/4 liters of high-quality vodka, 2 teaspoons of vanilla extract and 1 whole vanilla bean. Cover the mixture and allow it to age for two to three weeks.