Different varieties: there are three varieties of grapefruit according to different production areas. One kind of grapefruit with white flesh has a thick skin and a bitter taste, while grapefruit acid itself contains a variety of acidic substances, which is normal.

Immature: grapefruit contains a certain amount of naringin, which is bitter. When grapefruit is immature, it contains a large amount of naringin, and the acidity in immature grapefruit is also high, so it tastes sour and bitter.

excessive frostbite: grapefruit skin contains a lot of naringin, which has a certain bitterness. When grapefruit skin is frostbitten, the bitter components in grapefruit skin will penetrate into the pulp, resulting in a sour and bitter grapefruit.

Rot and deterioration: Normal grapefruit tastes sour and sweet. If grapefruit has rotted and deteriorated, it may make grapefruit bitter and thus unable to continue eating.