The Japanese Table
Dried Tofu, Noodles and Starchby Kazuyoshi Shitomi and Isao Kumakura
Food that has been preserved by drying is known in Japan as kanbutsu. These are eminently natural foods that have been part of the country's food culture for thousands of years. This third installment of our series on kanbutsu focuses on processed food products.
Natural foods have come into the mainstream of the Japanese daily diet, and recipes that feature traditional dried food ingredients known as kanbutsu are growing in number and popularity.
Freeze-Dried Tofu: Koya-dofu
The method of freezing and then drying foods developed mainly during the Edo period (1603-1867) has generated a wide variety of foods unique to Japan. Koya-dofu refers to tofu preserved by this process. An essential ingredient in the diet of Buddhist temples, koya-dofu takes its name from Mount Koya, the preeminent Buddhist temple complex in those times. Made where the climate is very cold, fresh tofu was first cut into thin slices and allowed to freeze outdoors naturally, then was dried in the sun and wind. Nowadays this process has been mechanized and koya-dofu is produced with modern freeze-drying equipment.
Nagano Prefecture supplies 90 percent of the national koya-dofu market, with the remainder produced in western Japan near Kyoto, Osaka and Nara. Tofu has become widely recognized as one of our most healthy foods, and among the great variety of tofu products, koya-dofu has the greatest nutritional value. It is particularly prized for its high levels of protein and calcium.
Koya-dofu is re-hydrated in warm water to about twice its dehydrated size before use in cooking. Koya-dofu no fukume-ni is a common dish, traditionally served as part of the New Year's menu, made by simmering koya-dofu in stock, sake, soy sauce, mirin and sugar.
Thin Wheat Noodles: Somen
The history of the slender wheat noodles called somen goes back 800 years. Somen noodles are made by continually working and rolling out wheat flour with salt and water into ever-longer ropes that are about the thickness of an index finger. These ropes of dough are lightly coated with oil to prevent drying, and set aside. Left to stand, the dough ripens and becomes elastic. Using two hand-held sticks, it is then stretched into threads and dried. Somen is the slenderest of dried Japanese noodles and has a cool and refreshing texture that makes it essential fare during Japan's hot and humid summers.
Somen can be either hand-stretched or machine-stretched, but hand-stretched noodles are prized as a luxury item for their superior taste and texture. Hand-stretched somen is produced in a two-day process during the cold months from November to March. It is stored carefully through the warm and humid rainy season (June and July) before being shipped to markets. For every year or two that the noodles are aged, their body and flavor increases, with two- to three-year-old somen bringing the highest value on the market.
Somen is simple to prepare. First, the noodles are boiled in plenty of hot water, then placed in a strainer and rinsed thoroughly in cold running water, loosening the strands to remove all the starch. Finally, the water is drained and the noodles transferred to a serving dish of ice water. Somen is served with a dipping sauce (tsuyu) and condiments such as chopped green onion, myoga, ground ginger root and sesame seeds. Somen tsuyu is made of konbu (kelp) and katsuobushi (dried bonito)-based stock flavored with soy sauce, mirin and sugar. These noodles may also be eaten in a hot broth during the winter.
Kudzu Starch: Kuzuko
The best-known starches used in cooking may be cornstarch and potato starch made from white potatoes, but there is a third, more traditional starch known as kuzuko, made from the root of the kudzu vine. This is a traditional starch that has a strong following in Japan. Compared to other starches, kuzuko boils to a smooth, firm, yet delicate texture; it is widely used as an ingredient in gourmet cooking and confectionery because it maintains textures after it has cooled.
Standard dishes that use kuzuko include simmered foods like ankake (liquid stock thickened with kuzuko to inhibit cooling) and goma-dofu (a savory kuzuko pudding with sesame paste). It is also used in many confections such as kuzu-kiri, a clear cake of boiled kuzuko cut into noodle-like strips and eaten with dark sugar syrup, and kuzu-zakura or kuzu-dama, a cake of bean-paste covered with kuzuko.
Kuzuko is the starch extracted from the root of the kudzu vine, a member of the legume family that grows wild all over Japan. Kudzu roots are dug up in early winter then crushed and the starch kneaded out. Through repeated processes of rinsing, kudzu is purified into a white powder. Cold water and a cold climate are essential in the purification process. The Yoshino region of Nara Prefecture meets these conditions and has produced the finest kuzuko for a thousand years.
Kazuyoshi Shitomi was born in Tokyo in 1925. He graduated from Waseda Jitsugyo Academy in 1943 and began working at Mantou, his family-run, Asakusa-based wholesale store specializing in kanbutsu dried foods. In 1965 he succeeded as head of the family. For about six years he contributed a series of articles to a cooking magazine based on visits to places throughout the country where kanbutsu products are made and has written and edited numerous other articles on dried foods. He is the author of Kanbutsu Nyumon [Introduction to Dried Foods].
Isao Kumakura was born in Tokyo in 1943. He taught at Tsukuba University from 1978 to 1992. Since then he has held the position of Professor of Japanese Culture at the National Museum of Ethnology, Osaka. Among his major publications are Tea in Japan and The History of Japanese Food.