Unagi, the Japanese word for freshwater eel, is an elongated fatty fish, rich and bold in flavor. Different than anago, its saltwater cousin, unagi is widely used in Asian cuisines and can never be eaten raw, as eel blood has toxins in it that can kill all animals. It's delicious when smoked, but it can also be pan-fried, sautéed, or incorporated into soups.
What Is Unagi?
When eating unagi, you're consuming a young eel that inhabited freshwater but that would have eventually grown and changed in appearance to enter the ocean to breed, just once in its lifetime. This fish lacks scales and is slippery to the touch. Because of its elongated shape, you are likely to find the fish butterflied and cut into square or rectangular fillets. Because of its potential toxicity, cooking it right is necessary.
How to Cook Unagi
Unagi is usually grilled over charcoal, but at home, you can either use a flat grill top or a nonstick pan with oil. Baked unagi is also a flavorful and easy-to-make dish. Simply season the fish, skin down, with sake and salt, bake it for eight minutes, and glaze with a sweet basting sauce made out of soy, mirin, sugar, and sake. For deep-fried eel, dredge the fillets in well-seasoned flour and fry for eight to 10 minutes. The ingredients in the sweet basting sauces used to enhance the flavor of the eel are important to the final taste of the unagi, and different restaurants maintain their own secret recipes. Prepare a thick sweet and salty sauce, and you won't be disappointed.
What Does Unagi Taste Like?
Unagi has a light and sweet flavor that's not overpowering and very palatable. The meat is soft and chewy, with a porous texture that makes it ideal for saucy preparations, as the meat soaks up all the juices, and the dish is always moist and flavorful. Unagi doesn't have a fishy aftertaste like a saltwater eel, but it's final flavor also depends a lot on the sauce used to glaze it or other more powerful ingredients in the recipe.
Unagi vs. Anago
Simply put, unagi is the eel whose young are born in the sea and go to freshwater to live, only to come back many years later to mate, and anago is the eel whose entire lifecycle happens in saltwater. Unagi is richer, firmer, and fattier; anago is fluffier in texture and less flavorful. Chances are that if you're eating eel over rice, it's unagi, and if you're eating it in sushi form, it's anago.
Japanese eel (Anguilla japonica) is the only proper unagi, but other types of eels are suitable for human consumption, such as longfin eel, European eel, and American eel. If you are looking for unagi, check with your fishmonger before buying it, as eel could come from other species and is most likely farmed and not wild caught.
Well-prepared unagi combines a rich flavor, a bit like pâté, with an appetizing texture—crisp on the outside but succulent and tender on the inside. Filleted and deboned, unagi is commonly glaze-grilled, a dish known as unagi no kabayaki. Kabayaki is a process in which the fish is cleaned, gutted, butterflied, and filleted into square pieces. The eel is skewered and grilled with sweet basting sauce and is typically served over steamed white rice. Unagi also can be used as an ingredient in other Japanese dishes like unagi don, in which the eel is sliced and served on a bed of rice. Sushi (unakyu) made with unagi is also pretty common fare.
Where to Buy Unagi
Vacuum-sealed unagi no kabayaki is often available at Asian grocery stores, but you can also buy the fish online, either vacuum sealed or frozen. The availability depends on the time of the year and how many eels you're willing to buy. Many Asian markets will sell the eel already seasoned and sauced, with many different flavors from BBQ to smoked. Some markets will carry fresh eel, but it is always best to call ahead and to ask which type of eel they have and if they could certify it is proper unagi.
Store the unagi in the same environment you bought it in, most likely in your freezer. If you already prepared it, consume leftovers within a day or two for the best flavor, but do not refreeze a piece of fish that has already been thawed and cooked. If you have fresh eel, remove the skin immediately, and either cook or freeze it, wrapping the fillets tightly in plastic wrap.