What is uni sushi (sea urchin sushi)?

You might have seen it on a menu while out for sushi, but what does uni sushi mean? Well “uni” refers to the edible parts of the sea urchin. 

Normally, sea urchins might be something you’d try to avoid, as they can give you a painful sting while you’re swimming in the sea. However, the edible parts of the sea urchin are delicious, making sea urchin sushi a real delicacy in Japan. But just what is sea urchin sushi?

What is uni sushi? 

The term sea urchin covers several species of spiny sea creature, which are usually spherical and can be found around the world. So then what is sea urchin sushi made of? 

The gonads of sea urchins are eaten in various locations around the world, including Japan, Italy, Chile and New Zealand. In Japan, the orange lobes of the gonads are usually served raw as sashimi or sushi. It’s particularly popular as a type of nigiri sushi, paired with only sushi rice and sauces like wasabi or sushi soy sauce. This allows the diner to focus their attention on the flavours of the sea urchin.

What are the main types of uni sushi? 

First of all, it’s important to note that there are several kinds of sea urchin eaten in Japan. Many come from the waters around the northern island of Hokkaido, including the popular marasaki (purple) uni. Others, such as aka (red) uni, usually come from further south.

The type of uni, as well as the freshness and colour, influences the price sea urchin (and uni sushi) sells for. Generally though, uni is one of the most in-demand of all sushi ingredients. Each kilogram of high-grade uni can cost hundreds of dollars and Japanese diners eat around 80% of the world’s sea urchins.

Shiro uni 

This delectable dish combines raw sea urchin with sweet white shrimp (shiro ebi). Unsurprisingly, it comes from Hokkaido, Japan’s sea urchin hotspot.

The shrimp is usually marinated in sweet vinegar, before it’s placed on top of the rice ball in a nigiri sushi dish. The uni is then spread on the shrimp.

Shiro uni is sometimes presented to those enjoying an omakase meal in a high-end Japanese restaurant. Omakase means “I’ll leave it up to you”, which allows the chef to choose a series of seasonal, high-quality dishes for their guests.

Aka uni

Sometimes known as bafun uni, aka uni can be red, orange or dark yellow. It has a slightly stronger, sweeter and more complex flavour than some other types of uni. It also lasts longer, typically. All this means it’s one of the most expensive varieties of uni.

Although some restaurants might give you aka uni sushi wrapped in nori (seaweed), most will make it a nigiri dish to let you focus on the unique flavours.

What does uni sushi taste like?

Uni sushi has a distinctive flavour, which can take time to grow on some people. It’s rich and savoury, with a creamy texture like butter. Although it is soft and melts in your mouth, there should still be a little firmness there, as there is with well-cooked tofu.

Some varieties of uni might have a stronger flavour, while the sweeter types are usually the most expensive. Ensui uni (saltwater uni), for example, is saltier than other varieties and is stored in a saltwater solution to keep that flavour.

What are the nutritional benefits of uni sushi?

Like most seafood, sea urchin is high in protein and healthy fatty acids like omega-3. The protein is good for building and repairing muscles, while those fatty acids have a whole host of benefits for heart health and brain health.

There are also plentiful vitamins and minerals to be found in uni, helping you to top your levels up. These include vitamin B12, vitamin E, vitamin A, iodine and zinc.

However, one thing to be aware of is that some people might be allergic to sea urchin.

So, generally speaking, uni sushi is both healthy and delicious. If you see it on a menu in your local sushi place, the only thing that might put you off is the price tag attached to this true Japanese delicacy. If you’d rather start with something a little more familiar, then you can experiment with a huge array of mouthwatering sushi flavours at home using oursushi making kits.