In a 4-cup (1 litre) glass jar, combine the brown sugar, vodka, coffee beans and caramel pieces. Tightly seal the jar. Vigorously shake for 5 minutes or until the caramel is almost completely dissolved. Let infuse for 12 hours at room temperature. Strain the mixture. The coffee liqueur will keep for 3 months in a glass jar at room temperature. Serve over ice, in coffee or in a cocktail (such as a White Russian).