Nori

Nori is the Japanese name for a range of edible seaweed species, mostly of the red alga Porphyra including P. yezoensis and P. tenera, which is also sometimes called laver. The finished products are made by a shredding and drying on racks. Japan, Korea, and China are the current major producers of nori, with total production valued at up to US $2 billion per year.

Nori is commonly used as a wrap for sushi and onigiri. It is also a common garnish or flavoring in noodle preparations and soups. Nori is often toasted prior to eating ("yaki-nori" in Japanese). A very common and popular secondary product is toasted and flavored nori ("ajitsuke-nori" in Japanese), in which a flavoring mixture (variable, but typically soy sauce, spices and sugar in the Japanese style or sesame oil and salt in the Korean style) is applied in combination with the toasting process. Nori is also made into a soy sauce flavored paste noritsukudani, and sometimes it is used as a form of food decoration. 

Production and processing of nori by current methods is a highly advanced form of agriculture. The biology of Porphyra, although complicated, is well understood, and this knowledge is used to control virtually every step of the production process. Farming takes place in the sea where the Porphyra plants grow attached to nets suspended at the sea surface and where the farmers operate from boats. Click the image to see an aerial view of Nori nets spread out in the Ariake Sea around Kyūshū in Japan.

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 18×20 cm and 3 grams in weight.

In Japan, over 230 square miles (600 square kilometres) of Japanese coastal waters are given to producing 344,470 tons (350,000 tonnes), worth over a billion dollars. 

Nori is a source of vitamin A, B, C1, iodine, protein (1/5 of milk <100ml>, 1/5 of an egg), fiber (31.2mg/100g), and carotene. It also contains a great deal of calcium and iron. For example, 100g of yaki-nori has 4.4g of protein, 280mg of calcium, and 11.4mg of iron.