
Watermelon is the large, fleshy fruit of Citrullus lanatus, a vine-like annual of the gourd family, prized for its very high water content.
Mildly sweet and clean, dominated by a fresh, watery character with a soft melon aroma and very low acidity.
A few cubes or a wedge of flesh are muddled or juiced to carry a fresh, watery sweetness into the build, and the drink is then shaken over ice. Because the flesh is fragile and floods thin juice, it cannot be cut into firm structural garnishes the way citrus can; the tough rind, however, can be tenderised and pickled into a firm, crunchy edible garnish.
As a garnish it swaps loosely for another decorative fruit, but where the drink is built to taste of watermelon it is essentially not substitutable; its mild sweetness can be rebuilt with a touch of syrup and its light, watery body with a low-viscosity juice, yet the fresh melon character itself cannot be replaced by a concentrated or candied fruit.
Grown on a trailing annual vine, the fruit is enclosed in a thick rind around juicy flesh that is roughly 91–92% water; flesh colour may be red, yellow or white, red being the most common cultivated form. Though botanically a gourd alongside pumpkins, cucumbers and squashes, it is eaten worldwide as a fruit.
Cut flesh is highly perishable and weeps watery juice; refrigerate covered and use within a day or two.
The genus Citrullus is native to Africa and has been cultivated since ancient times, with remains dating back more than 4,000–5,000 years in northeastern Africa; the sweet dessert watermelon is regarded as having emerged from African wild ancestors.