London Japan Kitchen Bob


In making sushi, nori is an essential ingredient. A black dried seaweed that forms a paper to wrap the rice and fish in. Most Japanese people only buy a good nori so some don't know a lot about the various grades of nori.

Different nori grades have their own unique flavor and texture. The (Japanese) grade rank follows: gold, silver, yellow, green, and red/purple. The gold grade is the highest quality, and it is characterized by its smooth texture, delicate flavor, and almost black in color. Silver grade is a little less expensive than gold but it's still hard to distinguish unless you eat it side by side.

Yellow grade is the black sheep of nori. It is thick as it uses a dense net of cheap seaweed, giving a strong chewy texture. It is greener in colour, with a strong algae like flavour. Basically tastes blegh.

Occasionally our supplier throws it in as an alternative when the gold grade stuff isn't available, but we really don't want it as it is too noticable. Oddly the grade below that, green, is an acceptible flavour that we WOULD use in sushi. I have no clue why the green doesn't come before yellow.

You can buy Yamamotoyama Yellow grade nori for around £11 on Amazon as of April, 2023. The same company exports this but doesn't sell this grade Nori to the Japanese.

#Sushi #Nori #JapaneseFood

Tuna sushi is more expensive than salmon. Since we are not an official sushi restaurant, we do not bother purchasing tuna meat. Sushi fish suppliers typically buy their fish from Billingsgate market by weight and debone and cut it into different sections.

During the cutting process, the bits of tuna meat that have been scraped off the bones are called naka-ochi, meaning “inside drop.” These are cheaper than a chunk of tuna meat because the odd bits and pieces do not make for pretty, presentable sushi. Often, a sushi chef will mince this meat and mix it with spring onion to make Negitoro sushi.

We first ordered naka-ochi from the supplier Jo Showa and then from Atariya. When it arrives, it has a vibrant red color due to its freshness, and we try to use it up before the characteristic browning of tuna occurs.

The interesting point to note is the species of tuna from which this naka-ochi comes. Jo-Showa was a mix of Yellowfin tuna and Atlantic bluefin tuna (honmaguro, or real tuna). You can distinguish between the two by their color; Yellowfin tuna has a translucent red color, whereas Atlantic tuna is cloudy red. We were lucky to find some fatty toro tuna in there, which is seen by its more pinkish color. A toro tuna comes from Atlantic tuna, as the Yellowfin rarely has a fatty part.

The flavor of the two species also differs. Yellowfin tuna has a less tuna-like flavor, which is less distinct than the strong metallic, blood-like flavor of Atlantic tuna. Whether someone likes this taste is a matter of preference. Our chef Tonton gets excited when she sees Atlantic tuna because it is a rarer ingredient and her favorite.

Next, the naka-ochi from Atariya was 100% bluefin tuna. It had fewer toro parts, but Tonton was elated. She ate it while talking about how expensive it has become in Japan due to tuna depletion. It was delicious, but I preferred the Yellowfin tuna. Bluefin had a metallic taste like bonito (skipjack) sashimi.

Next time you eat Tuna sushi, check out which species you may have.

#Sushi #JapaneseFood #Tuna #Honmaguro #Nakaochi

One time we ordered some delicious fatty toro tuna which can frozen from the company. To time its freshness, we thawed it just several hours before serving it to a customer. You could see our chef's surprise when the tuna slice was stiff as cardboard just before the sushi was completed!

Rigor mortis in dead fish starts around 5 hours in. So this Tuna must've been frozen on board the boat as soon as it was caught!

Can we still use it? I tried chewing on it, but it had a very unappealing texture. It was like chewing rubber, you chew and chew but it doesn't break down. Eventually I pulled it out of my mouth and threw it away. That was a waste of prized sushi.

So we waited for another hour and at this point the meat became flaccid again. This time the tuna sushi melted in my mouth.

This only happened once for us, but it gives us a glimpse of the different degree of freshness from different fishing methods. Most fish caught in the UK won't need a fancy on-board freezer as it will be caught close to the coast.

#Sushi #RigorMortis #Tuna #JapaneseFood

You probably notice sushi tuna comes either in a vibrant red colour of a dull brown colour. Salmon is less obvious, but you can get a beautiful popping orange or a white-pinkish colour. Why is this?


When it is just caught and still very fresh, its color is a bright and deep red. This hue is so striking that it can almost seem unreal. The reason for this intense color is due to the oxygenated blood in the tuna.

However, as tuna ages, the color of its flesh can change from red to brown. This is because the oxygen storing myoglobin in the flesh breaks down and loses its oxygen, which causes the meat to become darker in color. While brown tuna is still safe to eat, it does not look as appetizing as fresh tuna. This difficulty remains when we freeze tuna, so we don't store tuna that often. In our kitchen, we marinate the brown tuna with flavour to mask the colour.


A freshly caught salmon also has a beautiful color, but it can vary depending on the type of salmon and its fat content. Salmon obtains its distinct pink colour from its diet containing the pigment astaxanthin. This colour is brought out as a popping orange hue in the trout “salmon” species due its lean meat.

Atlantic salmon, on the other hand, has a creamy pink color, especially in the females towards spawning season. The creamy hue is due to the presence of fat in the fish's flesh. Farmed salmon naturally has a high fat content, but during Autumn males tend to have better colours than females for this reason too.

Lastly, the pigmentation is also influenced by freshness and machine cut. A salmon meat that has been in contect with moisture (from a machine cut) or lost its freshness will become slightly dull, and the fine white fibres in the meat will be less distinct.

#Sushi #JapaneseFood

Sushi grade fish is an essential ingredient when creating sushi. When we receive our raw half sliced Salmon, the first thing we do is cut it into smaller chunks and freeze it as quickly as we can. I'll pass down the knowledge of our sushi chef Tonton on how to preserve fresh fish.

Scottish farmed salmon is considered sushi grade without freezing. This is because parasites in Scottish farmed salmon is low, making it safe to eat raw. When it comes fresh, it usually lasts around 5 days when stored correctly.

How do you determine if the salmon you have is fresh? A fresh fish barely has any fishy odor. If it smells and liquid has been seeping out, it is likely not fresh. Another way to tell is the firmness of the meat. With rough handling (Don't flex the salmon meat!) and age, the body of the meat separates by the white lines.

Once we cut the salmon into smaller chunks, it is time to wrap the meat. Wrap the salmon with paper first, then a disposable J-cloth to prevent condensation and freezer burn. This will help maintain the salmon's delicate flavor and texture.

If you plan on using the salmon within a few days, store it in a sealed container or wrap it in plastic wrap and keep it in the refrigerator. But if you need to store it for longer, it is best to freeze it. To freeze it quickly it is best not to pack the wrapped fish in a single solid chunk. The salmon will will be pretty much fresh for a very long time if you ignore texture change from the gradual freezer burn. When we want to use it, ideally defrost it overnight so that the meat fibers will equally thaw.

While it is possible to defrost using the microwave in an emergency, we have ended up with frozen and semi-cooked salmon this way so I wouldn't recommend it.

#Sushi #JapaneseFood #Salmon