한국국제교류재단

Laver has long been an important part of the Korean diet. Not only is it tasty and nutritious, it is also one of the country’s few exported sea products competing with canned tuna for first place. In the West, laver was once called “black paper” and was not relished as a food item but today, it enjoys growing popularity as a food full of micronutrients but low in calories.

Laver is the most produced and consumed seaweed in Korea. Initially dark black and glossy, laver turns green when toasted. The paper-like dried laver is usually sold by tot, a unit of 100 sheets.

Toasted laver is a favorite side dish of Koreans. Sheets of dried laver are brushed with sesame or perilla oil and sprinkled with a pinch of salt, lightly toasted and cut into rectangular pieces to wrap around rice. These days, olive oil is often used in place of sesame oil.

Everyone recognizes a food that tastes good. This is certainly true for laver. Called gim in Korean, laver belongs to the genus Porphyra, which includes some 70 kinds of coldwater seaweed that are consumed as food ingredients wherever they grow because of their excellent taste.

On the shores of Ireland, Scotland and Wales, rocks covered in laver are a common sight. Laverbread, a delicacy nicknamed “Welsh caviar,” is enjoyed at breakfast by Welsh people. Made of stone laver, chopped and boiled long enough to make a puree, then rolled in oatmeal to fry in bacon fat, laverbread is nothing like usual bread but was likely given its name because it was a staple for the people along the Welsh shoreline.

In Korea, laver is most commonly eaten in the form of thin, dried paper-like sheets rolled up with rice inside. Dried laver sheets can also be lightly toasted over a fire, plain or brushed with sesame oil and sprinkled with salt. Biting into the thin laver sheet makes a crispy sound that stimulates the appetite. Toasted laver can be crumbled over noodles with stir-fried vegetables as a garnish or mixed with crushed sesame seeds to coat rice balls. Gimjaban, dried and crushed laver pieces seasoned with sauce, is a popular side dish, and gimbugak, laver brushed with rice starch and deep-fried, is eaten as a snack.

In Japan, too, laver is enjoyed in thin dried sheets. It is a particularly important ingredient for sushi, and when the Japanese eat ramen, they often add a thick piece of laver on top. In China, laver is dried in the shape of flattened balls, from which pieces are torn off to cook in soups or stir-fried dishes.

The floating method with laver mats strung together and hung onto buoys made deep-sea farming possible, greatly increasing productivity.

Cultivated laver is harvested several times from late November to February the following year. It is then dried by machine in factories. Due to the intensive labor required, the traditional way of drying laver in the sun is disappearing.

Trio of Tastiness
As a Korean joke goes, “Adding laver flakes to soup is cheating,” so great is the power of laver in making food taste good. In fact, there is a reason for the tastiness. The typical elements of the pleasant, savory taste known as gamchilmat in Korean (umami in Japanese) are glutamic acid, inosinic acid (IMP) and guanylic acid (GMP), flavor enhancers at the level of nucleic acids. Green onion and kelp, often used in East Asia to add flavor, as well as onions, carrots and tomatoes, often used in Western dishes, contain a lot of glutamic acid. Inosinic acid is abundant in beef, chicken meat, chicken bones and anchovies, whereas mushrooms such as shiitake, porcini and morel are rich in guanylic acid.

Laver contains all the three flavor enhancers. The taste produced by this trio is the result not of addition of the three but their multiplication. Moreover, laver contains various free sugars, which produce a pleasant, sweet flavor.

“Though the roots are attached to the rocks, the plant has no stems and spreads wide over the rocks. It is dark purple and sweet and tasty.” This description of jachae (“purple vegetable”) comes from the “Register of Heuksan Fish” (Jasan eobo) by Jeong Yak-jeon (1758-1816), the first encyclopedia of sea organisms in Korea. A kind of red algae, jachae grows attached to rocks at the root-like end of its long, broad leaf; it is indeed an accurate description of laver in shape, color and taste. The surface of the fast-growing laver is lustrous, and its dark reddish color results from the absorption of sunlight by pigments such as chlorophyll, carotenoid and phycobilin. When this seaweed is roasted, carotenoid and phycobilin are destroyed by the heat and only chlorophyll remains, revealing the green color.

Laver’s nutritional composition makes it a good food ingredient. Though containing 42 percent protein and 36 percent carbohydrates, dried laver does not provide enough protein overall. Consuming one sheet of dried laver (3g) a day provides only 2 percent of the daily protein requirement. However, laver is rich in micronutrients such as vitamins and minerals, containing 10 times more minerals than plants growing on land.

Rich in Micronutrients
Laver is not only rich in beta-carotene and Vitamins C and E, but also in Vitamin B12, iron and omega-3 fatty acid, which can be lacking in a vegetarian diet. It also contains enough iodine to make up for such deficiency, though the amount is less than in other kinds of seaweed. That is why laver was regarded as a medicinal plant in England in the past. It is said that Welsh mothers told their children, “Eat your laverbread or you’ll get Derbyshire neck.” Many people of inland Derbyshire suffered a swollen neck condition called “Derbyshire neck,” caused by a lack of iodine.

Recently, much research has been conducted on the functional effect of porphyran, a polysaccharide component that is plentiful in laver. Found between cells in laver, porphyran plays an important role in laver’s survival in harsh marine environments. When porphyran enters the human intestines, it functions as fiber, reducing the occurrence of cancer and helping immunoregulation. It is also considered that the various antioxidants produced in laver to protect it from the stress of oxidation when exposed to ultraviolet light will prove beneficial to the human body.

Though an excellent food item in terms of taste and nutrition, laver has only relatively recently been artificially grown and made easily available. Laver farming imitates the natural way in principle. That is, following the way laver grows attached to the rocks and shells, laver spores are attached to shells or to mats made of twigs, which are stuck into mud flats using poles. The laver is submerged when the tide comes in and exposed to the air when the water goes out, just like laver naturally growing on the rocks.

Laver rolls are made by spreading steamed white rice on a sheet of dried laver, laying colorful fillings on top, and rolling the sheet up. Various types of gimbap with different ingredients are made these days, reflecting the changing tastes and preferences. © Topic

Old laver loses its freshness by springtime. It is made into gimbugak, a snack made of laver brushed with rice starch, then dried and deep-fried. © Court Cuisine Research Institute

Artificial Growing
By the 17th century, residents of coastal areas of Korea, Japan and China had begun to grow laver but had difficulties in getting the plant to reproduce.Without knowing why laver shows up again at the end of the fall after disappearing in the summer, they had to wait till fall to collect the natural conchospores to use in seeding. Then in 1949, Kathleen Mary Drew-Baker (1901-1957), a British botanist, discovered, while doing research on laver, that the Conchocelis rosea she had considered to be a different kind of seaweed was actually a stage in laver development. This was a breakthrough in artificial seedling collection.

Thanks to Drew-Baker’s research, the productivity of artificial laver growing improved rapidly, and seedling collection, previously possible only in the sea, could be conducted on land. The city of Uto in Kyushu, Japan, celebrated this achievement by calling Drew-Baker the “mother of the sea.”

Afterwards, the development of the frozen net method, in which spores are stuck onto nets and kept frozen and later placed in the sea when needed, led to more stable, mass production of laver. While the pole method of growing could only be done in coastal waters with a high tidal range, deep-sea farming began with the development of the floating method using laver mats strung together and hung onto buoys, further increasing productivity. Korea, one of the three major laver producing countries in the world, along with Japan and China, is first when it comes to laver exports. Korean laver is exported to about 100 countries in Europe, the Americas and Africa. Furthermore, with the recent development of diverse kinds of laver snacks, laver has become Korea’s top seafood export product.

A Food for Four Seasons
Laver rolls, or gimbap, are among Koreans’ lunch and snack time favorites. The laver rolls are made by spreading steamed white rice on a sheet of dried laver, laying a colorful assortment of stir-fried vegetables, pickled radish, ham and egg garnish on top, then rolling the sheet up. The glossy black laver sheet harmonizes with the rice and different ingredients inside to produce a wonderful flavor. It is fascinating to think that this food Koreans enjoy so much today is the product of collaboration of people around the world over a long period of time through the exchange of knowledge and information. Thinking of laver in this way makes it even tastier.