Common wheat-based foods in, for instance, Chinese cuisine (mantou/baozi, bing, dumpling skins) use white flour, and across East Asia, rice is served almost exclusively in its milled, white form. Responses to related questions on this sub explain that at least in the case of wheat, the large-scale production of white flour wasn't economically feasible until the invention of new milling technologies in the 1800s. When did the shift to refined grains *(from brown rice and brown, if not whole-grain flour) take place in East Asian societies, and how does the technological history of rice milling differ, if at all, from that of wheat?
I can’t give you an answer for East Asia in general, but the history of Japan’s switch to white rice is both interesting and horrible. It’s the story of a devastating and avoidable disease: beriberi, which sickened and killed victims into the 20th century.
In his book The History of Japanese Food (p. 31) Naomichi Ishige stresses that the rice that ordinary people have eaten for millennia was not completely unpolished brown rice. It was pounded on a mortar with a mallet to remove the hull and polish the rice. Removing the hull stripped away some of the bran, in contrast to today's brown rice, in which we can remove the hull and keep all of the bran.
The extent of the pounding depended on who was eating the rice. The rice fed to the Emperor was much more polished than the rice eaten by the servants. But even the white rice was darker than we imagine white rice, and very importantly, the pounding process didn’t entirely strip it of the essential nutrient Vitamin B1 or thiamine, which can be found in the bran.
The technology for dehulling and polishing rice advanced from mallets to wooden mills. Then in the seventeenth century, a new technology entered Japan via Chinese merchants: the clay mill. A description of the new technology from Rice, Agriculture, and the Food Supply in Premodern Japan by Charlotte von Verschuer and Wendy Cobcroft:
These were clay or "earth' hulling-mills tousu, made of wicker or wooden staves, filled with dried clay. Unlike wooden mills, the upper wheel of the tousu was worked in a full rotation by means of an articulated horizontal lever. According to the information given in the Hyakusho denki, clay mills hulled triple quantities, but they also resulted in losses, because 1.5 sho (2.7 litres) out of 1 koku (180 litres) of grain was reduced to flour and other quantities were spoiled and could no longer be husked. Thus the spread of clay mills probably remained limited to large estate holdings, since the losses were too great for individual holdings.
http://imgur.com/VFRaYd5 - I’ve uploaded a drawing of a mill being used, reproduced from the same book.
The new improved clay mills could remove the husk and bran of the rice, creating the perfect white rice: a luxury that soon proved popular with those who could afford it.
Susan Hanley gives an overview in her book Everyday Things in Premodern Japan: The Hidden Legacy of Material Culture (p.79)
As the economy grew, income rose, and just as farmers ate more rice over time, so did they eat better milled and more highly polished rice. In the seventeenth century, people ate rice that was partially polished; it appeared whitish, but part of the bran remained. Late in the century, a process was developed that completely removed the hull but left the bran. White, or highly polished, rice was considered the highest quality and tended to be eaten in cities. But those who could afford white rice often developed a vitamin B deficiency, and thus beriberi became known as the "Edo affliction." People who became ill while working as servants in Edo found that when they went back to the country, they improved, but it was not until the early twentieth century that the cause of this disease was discovered.
Beriberi manifests itself in several forms. It can damage the peripheral nervous system and the heart and circulation. In serious cases, it leads to heart failure, paralysis, wasting and mental confusion. Many leading figures of the 19th century, including the second last shogun, died either directly from beriberi, or were weakened by beriberi and succumbed to other causes. Even worse was infantile beriberi, in which a child breastfed by mother/wet nurse who ate mostly white rice, would die very suddenly of heart failure, between the age of two to six months.
The beriberi epidemic grew throughout the nineteenth century as more of the population was able to afford white rice. It hit the urban areas of Edo (later Tokyo), Osaka, and Kyoto hardest, so the conclusion most medical experts drew was that something about concentrated urban living caused the disease.
There were many purported cures for beriberi, including one that we now know worked: a school of traditional Chinese medicine prescribed barley (a whole grain) and red beans to beriberi sufferers. Unfortunately, this remedy was not universally used. And in a strange twist, the barley diet fell almost completely out of favour with the advent of Western medicine, pushed aside as an old superstition. Scientists thought beriberi was an infectious disease; therefore, foods couldn’t be the cure.
The beriberi “epidemic” reached its height during the Russo-Japanese war of 1904-05, during which most of the Japanese army came down with beriberi, causing 27,000 deaths. At the same time, the Japanese navy had identified the dangers of a white rice diet and managed to almost eliminate beriberi from its sailors. That wartime experience should have led immediately to changes, but it took a couple more decades of scientific and medical debate to break the previous consensus that beriberi had nothing to do with white rice.
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