Curaçao (/ˈkjʊərəsaʊ/ KEWR-ə-sow) is a liqueur flavored with the dried peel of the laraha citrus fruit, grown on the island of Curaçao. A non-native plant similar to an orange, the laraha developed from the sweet Valencia orange transplanted by Spanish explorers. The nutrient-poor soil and arid climate of Curaçao proved unsuitable to Valencia cultivation, resulting in small bitter fruit on the trees. But the aromatic peel maintained much of the essence of the Valencia varietal, and the trees were eventually bred into the current laraha cultivar, whose fruits remain inedibly bitter.
Curaçao liqueur was first developed and marketed by the Senior family in the 19th century. To create the liqueur the laraha peel is dried, bringing out the sweetly fragranced oils. After soaking in a still with alcohol and water for several days, the peel is removed and other spices are added.
The liqueur has an orange-like flavor with varying degrees of bitterness. It is naturally colorless, but is often given artificial coloring, most commonly blue or orange, which confers an exotic appearance to cocktails and other mixed drinks. Blue color is achieved by adding of food colorant, most often E133 Brilliant Blue.
Some other liqueurs are also sold as Curaçaos with different flavors added, such as coffee, chocolate, and rum and raisin.
Thanks to wikipedia.org