The grapefruit (Citrus × paradisi) is a large, round citrus with a thick yellow-to-blush rind and segments of juicy flesh that runs from pale white through gold to ruby pink — a fruit famous for its bracing combination of sour, sweet and a distinctive lingering bitterness. A relatively recent Caribbean hybrid, it is eaten halved and spooned at breakfast, juiced, broiled with sugar, and prized by perfumers and brewers for the high-impact thiol that gives it its unmistakable aroma.