Wax esters are composed of a fatty alcohol molecule and a fatty acid. Organic acids usually contain a carboxyl group (-COOH), and alcohols have a hydroxyl group (-OH). When an organic acid combines with an alcohol, an ester is formed. In wax esters, the hydroxyl group of the fatty alcohol combines with the carboxyl group of the fatty acid to form an ester bond. There are various types of wax esters, mainly classified as saturated wax esters and unsaturated wax esters.