Culinary Arts

What Is Sea Urchin? Learn How to Cook Sea Urchin in 5 Easy Steps

Written by MasterClass

Jun 4, 2019 • 3 min read

Spiny on the outside, buttery on the inside, sea urchins are a Japanese delicacy gaining popularity in the US.


What Is Sea Urchin?

Sea urchins are echinoderms (invertebrates related to starfish and sand dollars) with spiny spherical shells that enclose five segments of bright yellow-orange gonads (reproductive organs from either gender). Sea urchin gonads are the edible part of the sea creature. They are often called by their Japanese name, uni, since the country accounts for about 80 percent of global consumption.

Sea urchins live in the ocean, where they feed on algae and kelp, and are harvested wild by divers. Their flavor depends on a variety of factors, including diet, age, habitat, and species. Of the 950 species of sea urchin, only a few species are commercially harvested. Sea urchins are often identified by color, which gets confusing since so many of them are shades of red, purple, and green. Urchins are also identified by where they’re from, another confusing practice since often several types of urchin are found in one place.

6 Common Sea Urchin Varieties

  1. West Indian Sea Egg (Tripneustes ventricosus) is eaten raw or fried in the Caribbean and western Africa.
  2. Stony sea urchin, aka rock sea urchin or purple sea urchin (Paracentrotus lividus), is eaten in the Mediterranean, where it’s known as riccio di mare.
  3. Red sea urchin, aka giant purple sea urchin (Strongylocentrotus or Mesocentrotus franciscanus) is the largest commonly available urchin at seven inches in diameter. Its color ranges from red to burgundy, and it’s found on the Pacific coast from Baja California to Alaska.
  4. Green sea urchin, aka northern sea urchin (Strongylocentrotus droebachiensis) was once widely harvested in Maine, where it’s now considered overfished. The smallest commonly available urchin, at two inches diameter, are harvested in Canada.
  5. Pacific Purple sea urchin (Strongylocentrotus purpuratus) is smaller than red urchin at three to four inches in diameter and abundant on the Pacific Coast, especially California, where it’s threatening kelp forests.
  6. Chilean red sea urchin (Loxechinus albus) is found in Peru and Chile, where it’s commonly referred to as erizo (hedgehog). Multiple species of urchin found off the coast of Chile have been eaten for thousands of years.

What Does Sea Urchin Taste Like?

Sea urchins are full of sugar, salt, and amino acids, giving them an umami-salty sweetness. Like oysters, they tend to taste like the ocean they come from and the seaweed they feed on. (Uni from Hokkaido, Japan, for example, eat kombu, and therefore taste like kombu.) Male uni has a smoother texture than female uni, but all good urchins should have a buttery, melt-in-your-mouth texture and a complex, unique flavor that has been compared to eggs, lobster, foie gras, and fish roe.

Sea Urchin Nutritional Information

One 3.5-ounce sea urchin contains 1.83 grams omega-3 fatty acids, which support heart and brain health. Sea urchins are also a good source of protein and zinc, a mineral that supports the immune system and helps wounds heal.

How to Buy Sea Urchin (Sea Urchin Seasonality)

Sea urchin availability depends on species and location. Pacific purple sea urchins on the West Coast of the US are available year-round, while green sea urchins from Maine peak in winter.

How to Prepare Sea Urchin in 5 Easy Steps

  1. To prepare whole sea urchin, turn it upside-down over a bowl of water and use sharp kitchen scissors to cut an opening all the way around the mouth, being careful not to poke the uni inside.
  2. Gently pull off the part of the shell that was attached to the mouth to reveal the gonads. Invert the urchin over the water bowl to remove the liquid.
  3. Flip the urchin back over and use tweezers to remove any visible organs around the gonads. Use a spoon to gently pry gonads away from the shell.
  4. Dip the entire urchin in a small bowl of ice water to help keep the gonads intact, and then use a spoon to scoop gonads out of the shell and onto paper towels or a clean kitchen towel.
  5. Use tweezers to remove any other organs.

5 Ways to Cook With Sea Urchin

  1. Use raw sea urchin on top of rice to make uni sushi, or use it on top of decadent pasta.
  2. Uni is an emulsifier and can help thicken soups, custards, and sauces, such as mayonnaise, béchamel, and hollandaise.
  3. Add to omelettes or scrambled eggs. Try uni in Gordon Ramsay’s elevated scrambled eggs recipe.
  4. Serve raw on crackers, sprinkled with lemon juice.
  5. Add to a barbecue or yakitori marinade (the protein and fat will help with browning meat).

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