Ikura Sushi (Salmon Roe Profile)
What is Ikura (Salmon Roe)
Ikura (also called red caviar or salmon caviar) is salmon roe, and is one of the more popular items on the sushi menu, even though it is not native to Japanese waters. Not to be confused with tobiko or masago, it is readily distinguished because of its significantly larger size, like small, soft marbles, slightly transparent, and ranges in color from a deep, dark orange to a robust red. This is due to antioxidant pigments known as carotenoids which themselves are quite healthy, and also referred to as “red caviar due to the color. It is eaten often by itself, used as a garnish (also adding flavor), and in a number of different dishes such as scrambled eggs. At a restaurant, ikura sushi is typically prepared as gunkan-maki, which is a short strip of nori (seaweed) wrapped around the shari (bed of sushi rice) as otherwise the roe wouldn’t hold together. The cup-like gunkan-maki is the most effective presentation, holding the salmon roe in place. Often, a raw quail egg yolk is place on top, offering additional creaminess and complexity to the dish without interfering much with the unique flavor profile. Ikura is extremely popular in sushi, chazuke, or in ikura-don, which is a rice bowl topped with a layer of ikura.
While today ikura only refers to salmon roe, the name is believed to have originated with the Russian word “ikra,” meaning “fish eggs.” Both ikura and salmon were not Japanese staples until the 1980’s after a very successful Norwegian advertising campaign introduced the items to Japan, where it was quickly accepted and became a common menu item everywhere. Of course it can be difficult to find high quality fresh ikura as most has been previously frozen after harvest so that it can be stored and transported easily. You can tell the difference as fresh ikura has a firm, taught outer skin while thawed will sag a bit and can even leak, so the latter has a limited shelf-life when thawed.
Ikura has a slightly different taste during different parts of the year as well (it is “in season” during fall and winter but as it can be frozen is available all year round) depending on the curing process. While some “sujiko” (what the egg casing is called in Japanese) comes from wild salmon, the majority of the roe comes from farmed salmon, which guarantees a steady supply and also fortunately tastes no different than the roe from wild salmon. Prior to curing, the eggs are a deeper red color and slightly sweeter, but once cured, the ikura color lightens a bit and the now firm roe will pop in one’s mouth releasing a sweet, briny, and slightly fishy flavor richly enjoyed in Japan and around the world.
Ikura roe must be harvested at the appropriate time, however, as if harvested too late the skin can become more tough and thicker. The roe is typically harvested in mid-Fall, as the it is at its largest size and has the softest texture.
Fortunately, the roe is often harvested from salmon in a “no-kill” manner, via a c-section similar to how human babies may be born. Some, however, comes from wild salmon that are killed and the sujiko removed, but fortunately the fish is then sold as food so it does not go to waste. The sack that contains the roe is called the “skein in English” and the eggs are gently rubbed against a special sieve to remove them from the skein without damaging them. The sujiko is then washed and weighed, and then cured and graded before being sent down the supply chain to be eaten. Ikura also may come from a number of different salmon species, such as king or chinook salmon, pink salmon, sockeye or red salmon, coho or silver salmon, Atlantic salmon, or chum salmon.
Ikura is graded based on a number of factors, but the very first variable is the time the roe spends prior to being either cured or frozen. For every two hours the roe sits before processing, it is downgraded. The size and texture will tell the producer how mature the roe is, and is a factor as older ikura is typically better quality than if is harvested too early. Ikura is graded on a scale from 1-3, with 3 being the lowest quality (sometimes even called “industrial grade”). Premium grade ikura is given a 1 and standard grade is given a rating of 2. Interestingly, the highest grade, grade 1, can have a mix of eggs, some with shells more or less firm than others. These two are often separated for a consistent product, and some consumers prefer one over the other. There can also be eggs that are “dead,” for lack of a better word, and aren’t pleasant to eat and those are removed as well. Of course the higher the grade, the higher the price will be, though aside from the texture, the nutritional profile of the grades is very similar.
Curing The Roe
Ikura is harvested from salmon, and while the roe is still inside the egg casing it is still called sujiko and isn’t referred to as ikura until it is cured. The curing process is removing the eggs from the casing and very gently salting them to avoid breaking the roe, though curing recipes can differ as sometimes shoyu (soy sauce) and sake (rice wine) are used as well to add complexity. Traditionally, the roe was cured purely in salt, but most ikura is now cured in a soy sauce based marinade which adds a layer of complexity to the flavor as well as the necessary salt. As sujiko it is a much darker red, which lightens to a reddish-orange when cured and will firm up a bit.
In the US, for salmon roe to become ikura it must be salted to a minimum of 3.2% unless it is to be canned, or preserved for an extended period of time, and to about 3% in Japan. Wild roe from Alaska is typically soaked in a brine for a length of time based on the grade of the roe; the lower the grade, the longer the soaking period. This is done as a longer soak will strengthen the shell, creating a consistent product that can be stored and moved safely while also not being too soft when eaten (you want that nice *pop* when you bite into the roe). It is then placed in bento trays weighing usually 500 grams to 1 kilogram, and vacuum sealed in plastic. Frozen to a temperature of -15 degrees fahrenheit, it is sent out to resellers, and which is how most ikura is purchased. Unlike many foods, it is remarkable that it maintains its structure when thawed despite being frozen. Some producers will add preservatives as well to help the product last longer, so if you are purchasing it yourself at a grocery store be sure to read the label if you prefer to avoid them.