When it comes to making sushi, many people tend to pay attention only to the major steps – preparing rice and slicing fish. However, the art of sushi is more than that.
This article will explain some intricate work in sushi preparation necessary to offer the best sushi possible.
Preparation of sushi fish and knife-handling techniques are essential to the sushi-making process. Understanding the characteristics of common fish for sushi is also a great advantage.
The Basic Knowledge You Need to Know
Here, we will discuss the fundamental knowledge about the following topics: knives, common fish served at sushi restaurants, and characteristics of fish, respectively.
As underscored above, each component is crucial to sushi making. Therefore, extensive knowledge of such areas will empower you to offer the best sushi to your guests ultimately.
Now, it is time to dig deeper into each topic.
Knife Techniques
Before we get into it, we want to mention that different types of knives are required for various types of fish and/or steps for preparation. Therefore, you need a knife for specific use as well as a knife for general use.
You will most likely use three different kinds of knives in Japanese cuisine: yanagiba, deba, and usuba. Since an usuba knife’s sharp blade is ideal for cutting vegetables and fruits, the first two are sufficient for making sushi.
Yanagiba Knife
Yanagiba knife, also known as sashimi knife, is one of the best Japanese knives. This knife is common for slicing fish for sushi or sashimi because its long blade allows you to cut the fish in one stroke.
Handling a long knife requires a lot of experience and techniques. So, a 24-27 cm (9.5-10.6 inches) yanagiba knife with a thinner and pointy tip is ideal for a beginner sushi chef. On the other hand, professional sushi chefs handle a 29+ cm (about 11.4 inches) yanagiba knife.
Deba Knife
A deba knife demonstrates its excellent capabilities when fileting fish. Its thick, fine blade prevents damaging the flesh of fish when fileting.
In our blog detailing knives, you can find more information about Japanese knives and whetstones.
Typical Fish to Offer at Sushi Restaurant
As explained in our previous article, there are many types of fish the locals use as typical sushi toppings in Japan.
Tuna, bonito, yellowtail, and amberjacks are some representatives of akami, red-colored meat fish. The freshness of akami fish tends to fade quickly, making it crucial to choose the freshest fish possible.
Shiromi, a white-colored meat fish, is a counterpart to akami fish. Sea bream, cod, sea bass, and perhaps surprisingly, salmon all fall under shiromi fish. Other examples include Japanese flounder and threeline grunt, which are common at sushi restaurants in Japan. They tend to have firm flesh with an almost crunchy texture and lighter flavors.
Essentially classified as akami fish, the term hikarimono for silver-skinned fish is often used to differentiate them from other akami fish for its characteristics on many levels. Mackerel, sardines, and Pacific saury are typical examples of hikarimono at sushi restaurants.
Shellfish sushi has been on the dinner table in Japan since the 8th century. Today, the crunchy texture of shellfish is a favorite of many. Examples of shellfish for sushi are ark-shell clams, whelks, Japanese cockles, abalone, and scallops.
Apart from the ones above, there are many more kinds of toppings for sushi. Examples include ikura (salmon roe), tobiko (flying fish roe), sea urchin, eel, octopus, egg, and vegetables, including cucumber and pickled radish.
Sushi Preparation
Here, we will explain how to prepare fish for sushi, using some examples of fish – tuna, salmon, sardines, and scallops.
Tuna
The first important factor is how fresh it can be preserved. Tuna can be stored in a freezer at -60°C (-76°F) or lower for up to two months. This prevents color change and fat oxidation. It can be stored at -20°C (-4°F) for two weeks. This is a rough guidance since the storage time depends on the freshness of the tuna at the time of purchase and several other factors. It is better to consume it as soon as possible as the color will deteriorate.
Unless tuna is already in rectangular blocks called “saku,” the process starts by cutting the fish into saku blocks. It is better to do that by cutting the fish while still semi-thawed. You can refreeze them if you wish to use them later. When the saku blocks are ready, the preparation is complete.
Incidentally, if you have frozen saku-shaped tuna at hand or a refrozen saku block that you have cut into yourself, we recommend the following procedure for thawing it.
- Place the block in 40°C (104°F) water with 3% salt concentration, rinse off any frozen flakes on the surface, and then place it in water for 2 minutes (this will give it a bright color).
- When the surface becomes slightly thawed, take it out of the water and wipe off the excess water.
- Wrap it in kitchen paper and put it in the refrigerator. It will thaw in 2 to 3 hours.
As a precaution, the fish should not be left at room temperature to thaw, as it will swell, bend, and lose its juice.
Salmon
The first thing to note is that farmed salmon has been thoroughly tested and is safe to eat raw. However, in Western countries, natural salmon is often preferred because of growing concerns about using antibiotics and coloring agents in farmed salmon.
When eating raw natural salmon, it is important to freeze it beforehand to kill anisakis. Freezing salmon at below -20°C (-4°F) for 24 hours or above -20°C (-4°F) for 48 hours will kill the parasites. Usually, the temperature in a home freezer drops between -15 (5°F) and -18°C (-0.4°F). In other words, it takes about 24 hours to kill the parasites in the home freezer.
When thawing salmon, place it on a metal tray and store it in the refrigerator until it is completely defrosted. The thawed fish should be eaten within the day. For safety purposes, we do not recommend eating the thawed raw fish the next day.
In the preparation stage,
- Remove the skin from the salmon if it has any.
- Dehydrate the salmon with salt and release the excess water.
- Rinse it in cold water, wrap it in kitchen paper, wrap it in plastic film, and store it in the refrigerator.
This is the professional way to remove excess water, fat, and fishy smell.
Sardines
Hikarimono fish, like sardines, usually require more steps to prepare than akami or shiromi fish. Being very delicate, they quickly deteriorate without proper aging techniques. Due to the size being small, the preparation can be complex.
When storing the fish, it is pivotal to keep the fish in salted water with a bag of ice cubes to keep them as fresh as possible.
Here is the preparation process for sardines.
- Gently scale the fish using a knife. The belly is incredibly delicate, so try to minimize the damage to the skin as little as possible during the process.
- Cut off the head and tail, remove the guts, and leave them in the ice-cold salted water.
- Clean the fish using your hands with running water. Note that the skin is very fragile, so avoid washing them for a long time. Rather than fileting the fish with a knife, you can use your hands to filet the fish into a butterfly shape. This hand-fileting technique allows you to easily remove the spine of the fish and the small bones around it simultaneously.
- Salt the filets to remove excess odor. After the fish starts to sweat, rinse them with cold water to complete the preparation.
Because many hikarimono fish have a distinct taste, they are often served with green onions and ginger or seasoned with vinegar. After getting an order, you can marinate the filets, skin them, and make sushi with them in the way you like.
Scallops
Hotate scallops are a common topping for nigiri in Japan. While the ones produced in Hokkaido, Japan, have a reputation for their flavorful taste, you can find scallops from all over the world. Since the taste varies greatly depending on the region, you may need to change your preparation method accordingly.
The best way to defrost scallops is to do so very slowly. Rushing the process under running water can lead to a loss of flavor. You can soak them in water or a fridge for several hours or overnight.
As a professional tip, we recommend soaking them in freshwater if the scallops themselves are salty. This reduces the level of saltiness of the scallops. On the other hand, you should leave them in 2% salted water if they are less salty. If the salt level is correct, you can thaw them in a fridge. For this reason, it is necessary to taste the scallops first and change the defrosting method accordingly.
Then, remove the adductor muscle to achieve a better texture and wash them with fresh water to prevent food poisoning or infection. Remove the moisture from the scallops with a paper towel. This is the basic method of preparation for scallops.
While you can use the scallops as they are, “kombu-jime” is a highly recommended curing method to enhance the taste of scallops using kombu seaweed. Lightly salt the scallops and brush the surface of the kombu with sake. Sandwich the scallops with two pieces of the kombu and wrap them together with a plastic wrap. After letting it sit for two days, the cured and aged scallops will have a rich flavor transferred from the kombu.
The examples and information above are just a piece of what you should know about fish preparation. Our Sushi Masterclass courses can help you acquire extensive knowledge of preparation techniques and methods.
Learn More about Sushi with MJCA!
The proper preparation process must be addressed when serving great quality sushi. Each fish has its own preparation method, and the appearance and taste of the sushi on the finished plate make the process absolutely worthwhile.
MJCA will be happy to help you learn more about sushi preparation with our Sushi Masterclass courses: Foundation course and Advanced course. These courses provide access to a vast amount of information on sushi preparation and the essential steps involved in making sushi.
These courses are also available in our Grand Membership Plus, where you can access all current and future courses (a certificate or live sessions with a master chef are not included in the plan).
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