By Harold McGee
Guavas are the large berries of a bush or small tree in the genus Psidium, a native of the tropical Americas, and a member of the myrtle family, which includes the clove, cinnamon, nutmeg, and allspice trees. True to their family background, they have a strong, spicy/musky aroma (from cinnamate esters and some sulfur compounds). Their flesh contains hundreds of small seeds and many gritty stone cells, so guavas are most often used to make purees, juices, syrups, and preserves. The Spanish colonizers exploited their high pectin content to make a New World version of quince paste. Guavas are remarkable for a vitamin C content that can reach 1 gram per 100 grams, with much of it concentrated near and in the thin, fragile peel.