By Harold McGee
Mastic is a resin exuded from the trunk of a relative of the pistachio, Pistacia lentiscus, a tree native to the Eastern Mediterranean that now grows only on the Greek island of Chios. Mastic was chewed like chewing gum (hence its name, from the same root as masticate), and is also used to flavor various preparations, from breads and pastries to ice cream, candies, and alcohol (ouzo). The main aromatic components of the gum are two terpenes, pine-like pinene and woody myrcene. Myrcene is also the molecule from which the long resin polymers are built. The resin is not very soluble in water, so it must be ground fine and mixed with another powdery ingredient (flour, sugar) to help disperse it evenly in liquid ingredients.