Apr 18,2019
Kuzumochi is a traditional confectionery that has been around since the Edo period (1603 to 1868). Native to the Kanto region, particularly Tokyo, kuzumochi is the only fermented Japanese confectionery, as it is made by fermenting the starch in wheat flour. Kuzumochi was invented by Funabashiya, a confectioner with its main retail outlet near Tokyo’s Kameido Tenjin Shrine. Since the confectioner’s founding in 1805, it has endured various hardships, including the complete destruction of its store during the horrific Tokyo air raids during World War II. Yet Funabashiya has continued to preserve the taste of kuzumochi — a sweet for the common people — and its traditional production method.
For this article, we spoke with Shinohara Yuna, the public relations manager for Funabashiya, about the process of making kuzumochi.
There are two types confectioneries sharing the name kuzumochi, one in Kanto and one in Kansai, but they are completely unrelated. The kuzumochi primarily made in the Kansai region is a transparent type of mochi cake made by heating kudzu flour*1 with sugar and water and topped with kinako (roasted soybean) powder and black kuromitsu sugary syrup. The kuzumochi made in Kanto, however, is a whitish mochi made by fermenting wheat flour starch, which is served with a topping of kinako and kuromitsu.
*Kudzu flour is a powder made by refining the starch from the roots of kudzu, a perennial climbing plant in the legume family.
Funabashiya’s main store near the Kameido Tenjin Shrine
“There are a number of theories about the origin of Kanto kuzumochi. Our company was established in 1805. The founder of Funabashiya, Kansuke, occasionally visited the Kameido Tenjin Shrine and saw potential for selling sweets near the shrine. He set up his store near the shrine and began selling a sweet that was eaten in his hometown in Chiba, which he named kuzumochi.
“Wheat production was thriving in Chiba at the time. Wheat farmers would mix up wheat flour with water, steam it, and then eat it as a snack. The wheat-producing area was called Shimosa-koku Katsushika-gun back then. It is thought that Kansuke took the first character from Katsushika-gun, which is pronounced kuzu, to coin the word kuzumochi.”
Shinohara Yuna, public relations manager for Funabashiya Co., Ltd.
Later, to avoid confusion with the kuzumochi of Kansai, Kanto kuzumochi was written with hiragana replacing the first kanji character in the name. Even in Kanto, some other stores wrote kuzumochi with different kanji characters. Despite the different notations, kuzumochi was a favorite sweet among the common people in the Edo period and has been passed down for generations.
Kanto kuzumochi is made by fermenting the starch in wheat flour. The process, according to Shinohara, is passed down orally today, “because although there may have been documents detailing the kuzumochi production method stored at Funabashiya, the warehouse at Kameido was burnt to the ground and all records lost in the Tokyo air raids.”
But how exactly is kuzumochi made?
The Funabashiya main store near the Kameido Tenjin Shrine has a number of photographs on display, including this one of people lined up in front of Funabashiya in the Meiji period (1868 to 1912)
“The manufacture of kuzumochi begins with the fermentation of starch at factories in Gifu and Okinawa. First, the wheat flour is kneaded with water and the starch used for kuzumochi is precipitated out. The starch precipitate and fermentation water are placed in storage tanks lined with hinoki [Japanese cypress] wood. The mixture then undergoes lactic acid fermentation at ambient temperatures for 450 days. The lactic acid bacteria present in the wood drive the fermentation of the starch.”
Fermentation in progress in fermentation tanks in Gifu
Kuzumochi can normally be made with a fermentation duration of around one year. Funabashiya, however, has its own method in which the starch is fermented for much longer — 450 days! The production of kuzumochi does not end with its fermentation. After the fermentation stage is over, the drained raw kuzumochi is transported to Funabashiya’s production facility, where it is agitated in water-filled tanks four or five times to eliminate the sour fermentation odor.
The kuzumochi mixture being agitated
Next, the ingredients are dissolved in hot water, thickened, and poured into molds. The molds are steamed intensely for about 12 minutes and then cooled for about 50 minutes to firm up the cakes, which are then cut into bite-sized pieces. The process is now finally complete.
Although kuzumochi is considered a casual sweet for everyone, it actually involves much more time and labor than most people imagine.
Freshly steamed kuzumochi
“After many failed attempts, we found that kuzumochi fermented for 450 days had the best texture and elasticity. It does take a long time to make, but because it contains no preservatives, there is only a short window in which kuzumochi tastes its best. On the other hand, perhaps this purity reflects the past elan of Edo.”
We next asked the meaning behind the unusual trapezoidal shape that Funabashiya’s kuzumochi is cut into. “The truth is we don’t know why this shape took hold,” replies Shinohara. There certainly must be some significance to why they went with this shape, but the fact that the reason has been lost to the vagaries of time adds to the charm and mystique of kuzumochi.
The most important element to kuzumochi, which is a fermented food, is the lactic acid bacteria that promote the fermentation of the wheat starch. Despite the Tokyo air raids that inflicted heavy damage to Funabashiya, the raw ingredients for kuzumochi were miraculously spared, and its unique lactic acid bacteria have been passed down to the present day. Furthermore, a recent discovery has been the particular plant-derived lactic acid bacteria found only in kuzumochi — which has been trademarked as Kuzumochi Lactic Acid Bacteria®.
“We’ve taken the lactic acid bacteria at Funabashiya for granted for generations, but only with our eighth-generation owner, Watanabe Masashi, did we decide to commission physicians and researchers to examine what these bacteria really are. The researchers found a strain of lactic acid bacteria found only in kuzumochi. We trademarked the name of the lactic acid bacteria as Kuzumochi Lactic Acid Bacteria®. Recently, we launched a supplement that contains this lactic acid bacteria.
Plant-derived lactic acid bacteria have been gaining attention for their potential health benefits, such as regulating gut health. It’s a delight that such lactic acid bacteria can be found in a delicious form like kuzumochi.
“Kuzumochi is produced with plant-derived lactic acid bacteria. Japanese people have been consuming this bacteria for hundreds of years, so our current research is looking at whether this bacteria is well-suited to the Japanese physiology. In terms of health, kuzumochi is attractive because it is low in calories.”
Funabashiya has been expanding its product offerings to keep up with the times. In addition to selling supplements, it has added kuzumochi pudding made with kuzumochi ingredients as a signature offering and created Funabashiya Koyomi as a separate business venture targeting young women. Funabashiya, while preserving its traditional taste that comes from fermentation, is exploring new avenues as extensions of that tradition. Definitely try some healthy and delicious kuzumochi for yourself.
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