There are records showing that nori has been consumed since ancient days in Japan, and it has been one of the most common marine products. Nori is a general term for seaweeds that can be eaten, and it is said that “nura (slimy) ” had changed into “nori”. Itanori is made from these edible seaweed and dried into a paper-like shape. When itanori is lightly passed over a flame, it changes its name to “yakinori”, and the quality of colour and flavour are greatly increased after this process. Especially umami (flavours) is enhanced because the membranes of cells are changed by heat, and umami and aromatic components including glutamic acide (umami contained in kelp) and inosinic acid (umami contained in bonito flakes) can freely pass through the membrane, and the nori’s unique deliciousness and flavour can be tasted. When flavours are added to itanori, it is called “ajitsuke-nori”, and it is consumed a lot in western Japan.
Because nori tends to become stale easily, it is recommended that once a package is opened, place it in a sealed container and store in the refrigerator or freezer. When nori is stale, it can be used to make nori-tsukudani (boiled with soy sauce), Korean style nori (lightly toasted on a heated frying pan with sesame oil and then salt), and use in omelet or to dress boiled vegetables.
10 nori sheets are counted as ichi-jo (1 mat). This is because the unit to count thin items such as paper and nori is “jo” in Japanese. For example, ichi-jo of Japanese paper called mino paper is 48 sheets, Japanese writting paper for calligraphy is 20 sheets, and western style paper is 12 sheets.