The carob tree lent its seeds' name to the jeweller's carat
Every diamond weighed in carats carries a trace of a Mediterranean tree. The word travelled through Arabic from the Greek for carob seed, meaning little horn. The same tree yields a sweet pod used in place of chocolate and a gum that thickens countless processed foods.
The carob is an evergreen legume native to the Mediterranean and the Middle East, growing up to 15 metres with a broad, domed crown. It is thought to be an ancient survivor of a branch of the pea family that has otherwise died out. Its English names include St John's bread and locust tree, and its scientific name, like the Turkish goat's horn and the Yiddish word meaning ram's horn tree, points to the curved shape of the pods. Spanish settlers in Latin America later gave the carob's local name to unrelated trees simply because they also bore sweet pods.
Most trees are either male or female, so only some bear fruit. They flower in autumn, sometimes straight from the trunk, and the male blossoms have a notoriously unpleasant smell. Pods take a whole year to ripen; wild animals such as pigs eat the fallen fruit and scatter the hard seeds. The tree copes with drought and fairly salty soil, but it needs roughly half a metre of rain a year to fruit, and it is slow to pay off: full cropping usually arrives only when trees are 20 to 25 years old.
Harvesting remains mostly manual. Workers knock pods down with long sticks onto nets, taking care not to damage the flowers already forming for the next year's crop. The pods are dried, then broken apart to separate the seeds from the pulp. Pulp, about nine tenths of the pod's weight, is ground for animal feed or roasted and milled into flour.
Being a third to a half sugar by dry weight, carob works in powders, chips and syrups, often standing in for cocoa. The seeds supply locust bean gum, a common food thickener. About 50 cultivars are known, most of uncertain origin, and none has come from deliberate cross-breeding.
Source: Carob
