Look beyond this sea creature’s spiky exterior for an exceptional flavour experience.

Picture it: you’re sitting in a sushi restaurant and you see it—neatly arranged on top of a familiar cylinder of black nori is a peanut-butter-coloured substance with the outer texture of a tongue. This mysterious-looking delicacy is uni, known in English as sea urchin. Or more specifically, the gonads of a sea urchin. Despite the appearance of uni’s outer texture, biting down into a piece is nothing like biting a tongue. This ingredient is silky-smooth,like a rm custard with a sea-salty flavour.

Uni is harvested all over the world, but Japan’s supply of uni is primarily harvested from the waters surrounding Hokkaido, where many Japanese believe the best seafood is to be found. Despite this reputation, uni is still an acquired taste even for existing sushi lovers with its briny, tastes-like-the-bottom-of-the-ocean flavour. It can be fairly expensive, since each sea urchin only produces about five delicate “steaks,” which is only about enough for a single serving. In Japan it is most commonly consumed as sushi, but its custard-like texture makes it quite versatile in the kitchen.

While chefs all over the world have been experimenting with uni, the Japanese maintain their own unique twist on this delicacy. Salt-pickled sea urchin, or shio uni, is uni preserved in salt or with a combination of salt and sake. The uni pieces lose their shape during this process, so shio uni is not usually served as sushi but as an accompaniment to other dishes, or as a pâté-like paste. Another form of preserving uni is through a process of storing it in seawater, known as ensui. This process allows the uni to keep its shape during packaging and shipping, so that it can be served as sushi or sashimi at its final destination.

There is also a certain mystique that persists about uni as an aphrodisiac. This is not unusual considering uni is the sea urchin’s reproductive organs, although any direct link to reproductivity is likely more fiction than fact. However, there are a number of important vitamins and minerals such as vitamin A, vitamins B1 and B2, vitamin E, and zinc that are not only important for overall health but are linked to the promotion of sexual activity. Research has also found that uni contains a chemical neurotransmitter called anandamide, similar to that which is found in cannabis, which can have a euphoric effect on the human brain. This chemical is also believed to be essential to the reproductive process of the sea urchin. Although it may not have the same reproductive effects on humans, the euphoric effect of the anandamide in uni could be what is responsible for inspiring desire in humans.

Whether you believe in uni as an aphrodisiac or not, it is worthwhile to sample this unique delicacy. At the very least, you will get a nutritious experience!