Nori is a dried edible seaweed used in Japanese cuisine
It is made from species of the red algae genus Pyropia including P. yezoensis and P. tenera.
Production and processing of nori is an advanced form of agriculture. Farming takes place in the sea where the Pyropia plants grow attached to nets suspended at the sea surface and where the farmers operate from boats. The plants grow rapidly, requiring about 45 days from “seeding” until the first harvest. Multiple harvests can be taken from a single seeding, typically at about ten-day intervals. Harvesting is accomplished using mechanical harvesters of a variety of configurations. Processing of raw product is mostly accomplished by highly automated machines that accurately duplicate traditional manual processing steps, but with much improved efficiency and consistency. The final product is a paper-thin, black, dried sheet of approximately 18 cm × 20 cm (7 in × 8 in) and 3 grams (0.11 oz) in weight.
In Japan, over 600 square kilometres (230 sq mi) of coastal waters are given to producing 350,000 tonnes (340,000 long tons) of nori, worth over a billion dollars.
Raw seaweed is 85% water, 6% protein, 5% carbohydrates, and has negligible fat (table). In a 100 gram reference amount, seaweed is a rich source of vitamin A, vitamin C, riboflavin, and folate (table).
Nori is commonly used as a wrap for sushi and onigiri. It is also a garnish or flavoring in noodle preparations and soups. It is most typically toasted prior to consumption (yaki-nori). A common secondary product is toasted and flavored nori, in which a flavoring mixture is applied in combination with the toasting process. It is also eaten by making it into a soy sauce-flavored paste, nori no tsukudani. Nori is sometimes also used as a form of food decoration.
The use of Nori dates back to many centuries ago. It is impossible to know exactly when, but consideringthat Nori was mentioned for taxation in a law enacted in 702, it is at least 1300 years old. During that period and up until the 18th century, nori was produced differently than today and had the form of a thick paste.
It is in the Edo period (1603-1867) that the Japanese began to produce sheet Nori like today. For a stable production of high quality Nori, fully worked-out plans have been made until today such as breed improvement and the invention of a better culture method.
The word “nori” first appeared in an English-language publication in C. P. Thunberg’s Trav., published in 1796. It was used in conjugation as “Awa nori”, probably referring to what is now called aonori.
The Japanese nori industry was in decline after WWII, when Japan was in need of all food that could be produced. The decline was due to a lack of understanding of nori’s three-stage life cycle, such that local people did not understand why traditional cultivation methods were not effective.
The industry was rescued by knowledge deriving from the work of British phycologist Kathleen Mary Drew-Baker, who had been researching the organism Porphyria umbilicalis, which grew in the seas around Wales and was harvested for food (bara lafwr or bara lawr), as in Japan. Her work was discovered by Japanese scientists who applied it to artificial methods of seeding and growing the nori, rescuing the industry. Kathleen Baker was hailed as the “Mother of the Sea” in Japan and a statue erected in her memory – she is still revered as the savior of the Japanese nori industry.
In the 21st century, the Japanese nori industry faces a new decline due to increased competition from seaweed producers in China and Korea and domestic sales tax hikes.
The word nori started to be used widely in the United States, and the product (imported in dry form from Japan) became widely available at natural food stores and Asian-American grocery stores in the 1960s due to the macrobiotic movement and in the 1970s with the increase of sushi bars and Japanese restaurants.
Nori is vulnerable to heat, sunlight and humidity. If you leave the package open, Nori loses its taste, the scent and the mouthfeel. It is better to keep it in a moisture-proof container with the desiccant that’s packed with the product. The desiccant must be fresh. It is advisable to preserve it in the refrigerator.