Nori (Dried laver seaweed)

Types of Nori (Laver)

Seaweed is broadly categorized as red algae, which includes black laver, green algae, which includes green laver, and brown algae, which includes kelp and wakame seaweed. Asakusa nori, Susabi nori, etc. are in the red algae category. Hitoegusa and similar are in the green algae category. In Japan, seaweed belonging to the Porphyra genus is used as the raw ingredients for a dried and baked laver. There are 29 species of Porphyra seaweed that have been confirmed on Japan’s coastlines. Of those 29, the following five species are used the most.


Asakusa nori (Porphyra tenera)

This laver was once harvested in the Edo-mae sea (Tokyo Bay), and was dubbed “Asakusa nori” by the laver researcher, Kintaro Okamura, in 1909. It grows to a width of 10 cm and a length of around 50 cm. For many years it was the main, farmed seaweed of Japan, but once Nawate susabino nori appeared on the market, the level of production of Asakusa nori decreased and now it has become an endangered species. Laver made with Asakusa nori has a red tint when dried, but baking it transforms it into a beautiful green color. The texture of Asakusa nori is soft and smooth in the mouth compared to the firm Susabi nori.


Susabi nori (Porphyra yezoensis)

Originally, this species grew a lot from the Tohoku region to Hokkaido. It grows quickly compared to Asakusa nori, and since the finished product is a nice, black color, it very quickly took the nation by storm. Nawate susabino nori, which grows up to 1 meter in length, was discovered among the farmed Susabi nori. Currently, at least 90% of farmed seaweed is said to be a strain of Nawate susabino nori. The color of laver made from Susabi nori is dark and the closer to black it is, the more expensive it. It has a firmer texture with a glossy luster than Asakusa nori does, and it gives sushi a nice finish.


Suzi aonori (Ulva prolifera)

This laver grows on the coastlines and brackish waters where freshwater flows, throughout Japan. It is shaped in a 1 mm thick tube and is a bright green color. A high volume of branches grows from the thicker part, which is equivalent to the main shaft. It grows to be 20 to 80 cm in length. Sometimes it can even reach 2 meters or more. It is the most expensive green nori. Suzi aonori is a famous product of Shimanto River in Kochi prefecture and Yoshino River in Tokushima prefecture, where it is mass-farmed.


Hitoegusa (Monostroma nitidum)

This laver is named for its single-layer cell structure. The leaves are a bright green color, the membrane is soft and it grows to be about 10 to 15 cm. Hitoegusa spores are attached to a net to be farmed in mid-September, then harvested between December and May of the following year. The main area of production is Mie prefecture. Some are shipped raw, the products that will become ingredients in miso soup, etc., are almost all used as raw ingredients for tsukudani (preservable food boiled down in soy sauce).


Uppurui nori (Porphyra pseudolinearis)

The name “uppurui” comes from the fact that the Uppurui area of Izumo city, Shimane prefecture, has been the main location of production since long ago.

Uppurui nori is the representative species of the “iwa nori” (wild-harvested seaweed). Iwa nori only refers to seaweed growing in the wild in rocky areas, and farmed seaweed cannot legally be sold as “iwa nori” in Japan.


Laver Nutrition

About 40% of laver is dietary fiber. Furthermore, this dietary fiber is water-soluble, so you can expect it to be effective in relieving constipation. It also decreases the absorption of fat and sugar and controls increases in blood pressure and blood sugar levels. Laver is rich in protein and is even called the “soybean of the sea”. It contains about 40 g protein per 100 g, which is far higher than other seaweeds like kelp (about 9 g protein per 100 g) and wakame seaweed (about 2 g protein per 100 g). However, the content is not consistent, and may range from 30 to 55% depending on differences in the production site and the harvest timing. Laver that is brought out of the sea, dried, then repeatedly returned to the sea in the shallows, is high in protein. Furthermore, it has extremely high vitamin A, C and E content, as well as high levels of B vitamins and folic acid, making it a treasure chest of minerals and vitamins.

Although laver is rich in nutrients, because its cell walls are thick, the digestion rate of these nutrients is only about 50%. The rest is excreted without being digested. Then, the protein in the laver is processed by the digestive enzyme, pepsin and becomes Nolipeptide in its completely digested state, which is effective in lowering blood pressure. In addition, a component called Porphyran* is found among the carbohydrates in the laver, and this has sin moisturizing effects.

So why does laver have so many functions that isn’t found in other seaweeds?

Kelp and wakame seaweed grow their entire lives in the sea, but laver lives in harsh environments where it is exposed to low tide, so it is equipped with biological defense in order to protect itself from drying out and ultraviolet rays. Also, Porphyra 334**, extracted from laver, is also used in beauty products, such as shampoo, as a natural component derived from seaweed.

*Porphyran: The mechanism to protect laver from withering and drying out, even when left in the sun at low tide, is a sulfated polysaccharide substance unique to laver called Porphyran. Like hyaluronic acid, it has water retention capabilities, so it is used as an ingredient in cosmetics.

**Porphyra 334: A substance that absorbs UVA and protects the living body. The UVA blocking function doesn’t exist in brown algae such as wakame seaweed, or green algae such as aonori, but exists in even higher volumes in laver than in other red algae.


This section explains the trick to roasting nori (seaweed).

Grilling with bicho charcoal (high-grade charcoal produced from ubame oak) gives seaweed a wonderful aroma and flavor. Bicho charcoal doesn’t flame up, but the heat is strong. The trick is to just let it gently touch the net of the furnace, and quickly turn it over so that it doesn’t burn. It’s not easy to know when to turn it over at first, it takes some getting used to. If you sweep it over the heat, kind of like a broom, it won’t be heated evenly and part of it will burn. Instead of trying to grill it perfectly to 100%, it’s actually better to stop at about 90%, making sure it’s even through to all four corners. This gives the seaweed a vivid color and gives off a nice aroma. Using normal charcoal would cause flames, and the seaweed could catch on fire, and using gas causes moisture. The heat is too weak with electric appliances, so it takes a lot of time to grill. Bicho charcoal is hands-down the best way for roasting seaweed. It makes the seaweed crispy and melts in your mouth.


What nori are preferred by famous sushi restaurants?

Sushi restaurants like Sawada and Sushi Keita purchase nori seaweed from this store.


Sushi restaurants like Sushi Izumi purchase nori seaweed from this store.


Sushi restaurants like Irifune Sushi purchase nori seaweed from this store.


Sushi restaurants like Sukiyabashi jiro and Shinbashi Shimizu purchase nori seaweed from this store.


Sushi restaurants like Hatsune Sushi purchase nori seaweed from this store.


Sushi restaurants like Betenyamamiyako Sushi purchase nori seaweed from this store.


Sushi restaurants like Ginza Kyubey purchase nori seaweed from this store.


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