The açai berry is a round, black-purple drupe, slightly larger than a blueberry, which grows in branched twigs loaded with several hundred fruits each. It consists of a single large seed covered by a very thin layer of flesh (consisting principally of heart-healthy fatty acids) and an even thinner skin (whose dark purple color comes from antioxidant pigments called anthocyanins). In fact, the flesh and skin of the açai berry combined make up less than 10% of its total weight, which is why no one eats the fruit itself.

The edible part of the açai berry may be tiny but its nutritional density is great: As it contains nearly no moisture, its pulp is made up of nutrients alone! At the macronutrient level the principal constituents are heart-healthy fats, dietary fiber and protein, while at the micronutrient level we find a high concentration of anthocyanins + several vitamins and minerals. On the other hand, the açai berry contains practically no natural sugars and no caffeine at all.

Interestingly, some açai palms produce "açai branco", that is, white açai. The fruit actually looks green but the juice made with it has an off-white color. Essentially it is an "albino açai", that is, "normal" açai without the anthocyanins, the purple pigments that give açai its dark purple color.