kharrūbu

The carob tree (Ceratonia siliqua) is native to the eastern Mediterranean, thriving in the dry limestone hills of the Levant, Cyprus, and the Aegean. Its pods were known to Mesopotamian traders and recorded in Akkadian as kharrūbu — a word whose precise etymology within Akkadian remains uncertain, but which may be related to the root *ḫarābu* (to be dry, desolate) — apt for a tree that flourishes in arid conditions where other trees fail. Akkadian texts from the second millennium BCE reference kharrūbu among traded food products, and the pods were apparently consumed both as animal fodder and as human food in lean times. The carob pod's natural sweetness — due to high sucrose content — and its extraordinary keeping quality made it a useful provision for long journeys. Unlike grain, carob pods do not rot quickly.

The carob seed has a remarkable property that made it significant far beyond food: each seed weighs almost exactly the same as every other carob seed — approximately 0.2 grams. This botanical consistency made the carob seed a natural standard for weighing precious substances. The word 'carat,' the unit used for measuring the mass of gemstones and the purity of gold, derives from Arabic qīrāṭ (from Greek kerátion, diminutive of kéras, 'horn' — referring to the horn-shaped carob pod), which itself reflects the use of carob seeds as counterweights in goldsmithing balances. Every time a diamond's weight is stated in carats, the ancient Mesopotamian and Mediterranean carob-seed standard is still operative.

The word kharrūbu passed through Arabic as kharrūb (خَرُّوب), reached medieval Spanish as algarrobo, Portuguese as alfarroba, and entered English in the 15th century through medieval Latin carrubia and Old French caroube, settling as carob by the 16th century. The Catalan and Valencian variants — garrofa — survive in the region where carob cultivation remains significant. Saint John's Bread, another name for the carob pod, derives from the tradition that John the Baptist survived in the wilderness on carob pods — the 'locusts and wild honey' of Matthew 3:4 have been identified by some scholars as carob pods rather than insects, kharrūbu instead of grasshoppers.

Modern carob production is centered in Spain, Italy, Morocco, and Portugal, totaling around 100,000 tonnes annually. The pods are processed into carob powder (a cocoa substitute low in fat and free of caffeine), carob gum (a food thickener derived from the endosperm of the seed, used in ice cream, infant formula, and processed foods as E410), and animal feed. The chocolate substitute industry markets carob largely on its lack of theobromine — the substance in chocolate that is toxic to dogs. Carob chips, carob bars, and carob powder appear in health food shops as a gentler alternative to chocolate's stimulants. The Akkadian kharrūbu, the food of desert travel and famine relief, has been repackaged as a wellness product.