Oboro (おぼろ)

Oboro is made by using a grinding bowl to break down the meat of shiba shrimp or white fish, then seasoning with sugar, mirin and salt before removing the moisture over low heat. Oboro is used for bara-chirashi, futomaki (large sushi rolls), etc., and is also sometimes used between the topping and shari (vinegared rice) in nigiri sushi. This gentle sweetness and the shrimp aroma are essential for Edomae sushi. Making oboro is laborious work, so there are fewer and fewer Edo-style sushi restaurants that make their own oboro.

Oboro ingredients include shibaebi, mirin, sugar, egg yolk and salt. There is also a method that mixes in white fish and other shrimp, but the traditional Edomae sushi method only uses shibaebi due to it having the best sweetness, umami, fragrance, softness and color.

The antennae of shibaebi are long so they get tangled, and each individual shrimp must be separated. Next, the head and shell are removed, but the spines on the head portion prick your fingers, so it is cumbersome work. In addition, there is a possibility of sand remaining in the veins of the shrimp that must be carefully removed. The job takes nearly an hour with lightly boiling the shrimp, then grinding it in a mortar and boiling it down after. It is also possible to simplify the process by using a food processor instead of a mortar, but the food processor changes the texture of the minced meat, creates a difference in how fine the final grains are and how smooth it is.

Making oboro means to extract the moisture from the meat and grind it into grains as fine as sand, but if you take even a short break from the process, it may harden or burn, so you can’t look away for even a minute. The finished oboro is as fine as sand and looks smooth, but each individual grain should actually be soft and moist.

The nigiri-sushi toppings that use oboro include kobujime white fish meat, kohada that has undergone strong sujime, and Kasugo, among others. This is because adding a small amount of sweet oboro to a salty topping creates a balance of the sweetness and saltiness. However, recently Oboro isn’t necessarily used in cases of a lighter sujime in order to bring out the flavor of the fish. Incidentally, oboro can also be made with kuruma ebi, but the flavor and fragrance are stronger, so they end up fighting with other ingredients such as Tamagoyaki, Shiitake and Kanpyo, destroying the balance of flavors. It also makes for an oboro that is a bit tougher than shibaebi. Kurumaebi plays a supporting role in order to add color.

The typical sushi that feature oboro as the main role include oboro-maki and oboro nigiri. At most sushi restaurants, they are only served when specifically ordered.