Brew a pot of strong, good quality coffee to get that rich Kahlua flavor. it should be strong because a weak coffee won't transport the flavors into the final product. Once brewed, prepare to use the coffee immediately.
Once the pot is done, transfer it over to a large bowl. Add 4 cups of sugar and 1 Tablespoon of cocoa powder to the fresh, hot coffee and stir until dissolved.
Let the coffee mixture cool to room temperature. Once the sugar and cocoa has dissolved and the coffee has cooled, add the vodka stirring to combine. Pour the mixture into bottles.
Cut the vanilla bean into 3rds and drop one piece into each bottle. Put cap on. Your Kahlua is made. At this point you may add a cinnamon stick or orange peel if you like. This will give it a more dynamic flavor.
Store in a cool, dry place for 2-3 weeks. The vanilla needs this much time to infuse and the flavors need to settle into the coffee to give it that rich, liqueur flavor.
Once the time is up, strain it beforehand and then rebottle. Label and store in basement, cellar, or inside a closed box.