By Harold McGee
The watermelon is a distant relative of the other melons, the fruit of an African vine, Citrullus lanatus, whose wild relatives are very bitter. The Egyptians were eating it 5,000 years ago, and the Greeks knew it by the 4th century BCE. World production of watermelons is now double the production of all other melons combined. Watermelons are notable for the large size both of their cells, which are easily seen with the naked eye, and their fruits, which can reach 60 lb/30 kg and more. Unlike other melons, the watermelon consists of seed-bearing placental tissue rather than seed-surrounding—thus seed-free—ovary wall. “Seedless melons,” which actually contain small undeveloped seeds, were first bred in Japan in the 1930s. The classic watermelon is dark red with the carotenoid pigment lycopene, and in fact is a much richer source of this antioxidant than tomatoes! Recent years have brought yellow-orange varieties. A good watermelon has a crunchy, crisp, yet tender consistency, a moderately sweet taste, and a delicate, almost green aroma. External signs of quality are a substantial heaviness for the melon’s size, yellow skin undertones indicative of chlorophyll loss and thus ripeness, and a solid resonance when thumped.