By Harold McGee
The earliest sugar preserves were probably fruit pieces immersed in syrupy honey (the Greek term for quinces packed in honey, melimelon, gave us the word marmalade) or in the boiled-down juice of wine grapes. The first step toward jams and jellies was the discovery that when they were cooked together, sugar and fruit developed a texture that neither could achieve on its own. In the 4th century CE, Palladius gave directions for cooking down shredded quince in honey until its volume was reduced by half, which would have made a stiff, opaque paste similar to today’s “fruit cheese” (spreadable “fruit butter” is less reduced). By the 7th century there were recipes for what were probably clear and delicate jellies made by boiling the juice of quince with honey. A second important innovation was the introduction from Asia of cane sugar, which unlike honey is nearly pure sugar, with no moisture that needs boiling off, and no strong flavor that competes with the flavor of the fruit. The Arab world was using cane sugar by the Middle Ages, and brought it to Europe in the 13th century, where it soon became the preferred sweetener for fruit preserves. However, jams and jellies didn’t become common fare until the 19th century, when sugar had become cheap enough to use in large quantities.