The earliest record of soybean milk is on a stone slab of the
Eastern Han dynasty unearthed in China, on which is engraved a description of the making of soy milk in ancient kitchens. A tofu broth (
doufujiang) was used during the
Mongol Yuan. As
doujiang, this drink remains a common watery form of soy milk in China, usually prepared from fresh soybeans. The
compendium of Materia Medica, which was completed in 1578, also has an evaluation of soymilk. Its use increased during the
Qing dynasty, apparently due to the discovery that gently heating
doujiang for at least 90 minutes
hydrolyzed or helped to break down its undesirable
raffinose and
stachyose,
oligosaccharides, which can cause
flatulence and digestive pain among
lactose-intolerant adults. By the 18th century, it was common enough that
street vendors were hawking it; in the 19th, it was also common to take a cup to
tofu shops to get hot, fresh
doujiang for breakfast. It was already often paired with
youtiao, which was dipped into it. The process was industrialized in early
Republican China. By 1929, two Shanghai factories were selling over 1000 bottles a day, and another in Beijing was almost as productive itself. Following disruption from the
Second World War and the
Chinese Civil War, soy milk began to be marketed in soft drink-like fashion in Hong Kong, Singapore, and Japan in the 1950s. Soymilk was mentioned in various European letters from China beginning in the 17th century. "Soy milk" entered the English language (as "soy-bean milk") in an 1897
USDA report.
Li Yuying established Caséo-Sojaïne, the first soy milk "dairy", in
Colombes, France, in 1910; he received the first British and American patents for soy milk manufacturing in 1912 and 1913. J.A. Chard began production of "Soy Lac" in New York City, United States, in 1917. Harry W. Miller—an American businessman forced to relocate his factory from Shanghai owing to
World War II—was similarly compelled by the
US Department of Agriculture and the US dairy industry to use the term "Soya Lac" rather than "soy milk".
John Harvey Kellogg had been working with what he called "soymilk" at his
Battle Creek Sanitarium since 1930, but was similarly compelled to market his
acidophilus-enriched beverage as "Soygal" when it began commercial production in 1942. A string of 40 court cases against Rich Products between 1949 and 1974 finally established that non-dairy "milks" and imitation dairy products were "a new and distinct food", rather than inferior and illegal knock-offs.
Cornell researchers established the
enzyme lipoxygenase as responsible for the "
beany" flavor of soy milk made in 1966; the same research established a process for reducing or eliminating the bean flavor from commercial products. With
Tetra Pak cartons extending soy milk's
shelf life, Hong Kong-based
Vitasoy reintroduced the product to the US market in 1980 and brought it to 20 other countries within a few years.
Alpro similarly began production in
Belgium in 1980, quickly becoming Europe's leading producer. New production technology and techniques led to soy beverages with an appreciably more milk-like flavor and consistency in the mid-1980s. == Preparation ==