Sloe berries are small, dark purple fruits that grow on the blackthorn bush, scientifically known as Prunus spinosa. These berries are typically about the size of a pea and have a tart flavor, making them less suitable for eating raw. Instead, they are often used to make sloe gin, a popular liqueur in the UK. The sloe berry ripens in late autumn and is usually harvested after the first frost, which helps to soften its astringent taste. Besides their use in beverages, sloe berries are also rich in antioxidants and have been traditionally used in herbal remedies.