The Unlikely Inventor of the Automatic Rice Cooker

Cover, bring to a boil, then reduce heat. Simmer for 20 minutes." These directions seem simple enough, and yet I have messed up many, many pots of rice over the years. My sympathies to anyone who's ever had to boil rice on a stovetop, cook it in a clay pot over a kerosene or charcoal burner, or prepare it in a cast-iron cauldron. All hail the 1955 invention of the automatic rice cooker!

How the automatic rice cooker was invented

It isn't often that housewives get credit in the annals of invention, but in the story of the automatic rice cooker, a woman takes center stage. That happened only after the first attempts at electrifying rice cooking, starting in the 1920s, turned out to be utter failures. Matsushita, Mitsubishi, and Sony all experimented with variations of placing electric heating coils inside wooden tubs or aluminum pots, but none of these cookers automatically switched off when the rice was done. The human cook-almost always a wife or daughter-still had to pay attention to avoid burning the rice. These electric rice cookers didn't save any real time or effort, and they sold poorly.

This article is part of our special report, Reinventing Invention: Stories from Innovation's Edge."

But Shogo Yamada, the energetic development manager of the electric appliance division for Toshiba, became convinced that his company could do better. In post-World War II Japan, he was demonstrating and selling electric washing machines all over the country. When he took a break from his sales pitch and actually talked to women about their daily household labors, he discovered that cooking rice-not laundry-was their most challenging chore. Rice was a mainstay of the Japanese diet, and women had to prepare it up to three times a day. It took hours of work, starting with getting up by 5:00 am to fan the flames of a kamado, a traditional earthenware stove fueled by charcoal or wood on which the rice pot was heated. The inability to properly mind the flame could earn a woman the label of failed housewife."

In 1951, Yamada became the cheerleader of the rice cooker within Toshiba, which was understandably skittish given the past failures of other companies. To develop the product, he turned to Yoshitada Minami, the manager of a small family factory that produced electric water heaters for Toshiba. The water-heater business wasn't great, and the factory was on the brink of bankruptcy.

How Sources Influence the Telling of History

As someone who does a lot of research online, I often come across websites that tell very interesting histories, but without any citations. It takes only a little bit of digging before I find entire passages copied and pasted from one site to another, and so I spend a tremendous amount of time trying to track down the original source. Accounts of popular consumer products, such as the rice cooker, are particularly prone to this problem. That's not to say that popular accounts are necessarily wrong; plus they are often much more engaging than boring academic pieces. This is just me offering a note of caution because every story offers a different perspective depending on its sources.

For example, many popular blogs sing the praises of Fumiko Minami and her tireless contributions to the development of the rice maker. But in my research, I found no mention of Minami before Helen Macnaughtan's 2012 book chapter, Building up Steam as Consumers: Women, Rice Cookers and the Consumption of Everyday Household Goods in Japan," which itself was based on episode 42 of the Project X: Challengers documentary series that was produced by NHK and aired in 2002.

If instead I had relied solely on the description of the rice cooker's early development provided by the Toshiba Science Museum (here's an archived page from 2007), this month's column would have offered a detailed technical description of how uncooked rice has a crystalline structure, but as it cooks, it becomes a gelatinized starch. The museum's website notes that few engineers had ever considered the nature of cooking rice before the rice-cooker project, and it refers simply to the project team" that discovered the process. There's no mention of Fumiko.

Both stories are factually correct, but they emphasize different details. Sometimes it's worth asking who is part of the project team" because the answer might surprise you. -A.M.

Although Minami understood the basic technical principles for an electric rice cooker, he didn't know or appreciate the finer details of preparing perfect rice. And so Minami turned to his wife, Fumiko.

Fumiko, the mother of six children, spent five years researching and testing to document the ideal recipe. She continued to make rice three times a day, carefully measuring water-to-rice ratios, noting temperatures and timings, and prototyping rice-cooker designs. Conventional wisdom was that the heat source needed to be adjusted continuously to guarantee fluffy rice, but Fumiko found that heating the water and rice to a boil and then cooking for exactly 20 minutes produced consistently good results.

But how would an automatic rice cooker know when the 20 minutes was up? A suggestion came from Toshiba engineers. A working model based on a double boiler (a pot within a pot for indirect heating) used evaporation to mark time. While the rice cooked in the inset pot, a bimetallic switch measured the temperature in the external pot. Boiling water would hold at a constant 100 C, but once it had evaporated, the temperature would soar. When the internal temperature of the double boiler surpassed 100 C, the switch would bend and cut the circuit. One cup of boiling water in the external pot took 20 minutes to evaporate. The same basic principle is still used in modern cookers.

Yamada wanted to ensure that the rice cooker worked in all climates, so Fumiko tested various prototypes in extreme conditions: on her rooftop in cold winters and scorching summers and near steamy bathrooms to mimic high humidity. When Fumiko became ill from testing outside, her children pitched in to help. None of the aluminum and glass prototypes, it turned out, could maintain their internal temperature in cold weather. The final design drew inspiration from the Hokkaid region, Japan's northernmost prefecture. Yamada had seen insulated cooking pots there, so the Minami family tried covering the rice cooker with a triple-layered iron exterior. It worked.

How Toshiba sold its automatic rice cooker

Toshiba's automatic rice cooker went on sale on 10 December 1955, but initially, sales were slow. It didn't help that the rice cooker was priced at 3,200 yen, about a third of the average Japanese monthly salary. It took some salesmanship to convince women they needed the new appliance. This was Yamada's time to shine. He demonstrated using the rice cooker to prepare takikomi gohan, a rice dish seasoned with dashi, soy sauce, and a selection of meats and vegetables. When the dish was cooked in a traditional kamado, the soy sauce often burned, making the rather simple dish difficult to master. Women who saw Yamada's demo were impressed with the ease offered by the rice cooker.

Another clever sales technique was to get electricity companies to serve as Toshiba distributors. At the time, Japan was facing a national power surplus stemming from the widespread replacement of carbon-filament lightbulbs with more efficient tungsten ones. The energy savings were so remarkable that operations at half of the country's power plants had to be curtailed. But with utilities distributing Toshiba rice cookers, increased demand for electricity was baked in.

Within a year, Toshiba was selling more than 200,000 rice cookers a month. Many of them came from the Minamis' factory, which was rescued from near-bankruptcy in the process.

How the automatic rice cooker conquered the world

From there, the story becomes an international one with complex localization issues. Japanese sushi rice is not the same as Thai sticky rice which is not the same as Persian tahdig, Indian basmati, Italian risotto, or Spanish paella. You see where I'm going with this. Every culture that has a unique rice dish almost always uses its own regional rice with its own preparation preferences. And so countries wanted their own type of automatic electric rice cooker (although some rejected automation in favor of traditional cooking methods).

Yoshiko Nakano, a professor at the University of Hong Kong, wrote a book in 2009 about the localized/globalized nature of rice cookers. Where There Are Asians, There Are Rice Cookers traces the popularization of the rice cooker from Japan to China and then the world by way of Hong Kong. One of the key differences between the Japanese and Chinese rice cooker is that the latter has a glass lid, which Chinese cooks demanded so they could see when to add sausage. More innovation and diversification followed. Modern rice cookers have settings to give Iranians crispy rice at the bottom of the pot, one to let Thai customers cook noodles, one for perfect rice porridge, and one for steel-cut oats.

My friend Hyungsub Choi, in his 2022 article Before Localization: The Story of the Electric Rice Cooker in South Korea," pushes back a bit on Nakano's argument that countries were insistent on tailoring cookers to their tastes. From 1965, when the first domestic rice cooker appeared in South Korea, to the early 1990s, Korean manufacturers engaged in conscious copying," Choi argues. That is, they didn't bother with either innovation or adaptation. As a result, most Koreans had to put up with inferior domestic models. Even after the Korean government made it a national goal to build a better rice cooker, manufacturers failed to deliver one, perhaps because none of the engineers involved knew how to cook rice. It's a good reminder that the history of technology is not always the story of innovation and progress.

Eventually, the Asian diaspora brought the rice cooker to all parts of the globe, including South Carolina, where I now live and which coincidentally has a long history of rice cultivation. I bought my first rice cooker on a whim, but not for its rice-cooking ability. I was intrigued by the yogurt-making function. Similar to rice, yogurt requires a constant temperature over a specific length of time. Although successful, my yogurt experiment was fleeting-store-bought was just too convenient. But the rice cooking blew my mind. Perfect rice. Every. Single. Time. I am never going back to overflowing pots of starchy water.

Part of a continuing series looking at historical artifacts that embrace the boundless potential of technology.

An abridged version of this article appears in the November 2024 print issue as The Automatic Rice Cooker's Unlikely Inventor."

References

Helen Macnaughtan's 2012 book chapter, Building up Steam as Consumers: Women, Rice Cookers and the Consumption of Everyday Household Goods in Japan," was a great resource in understanding the development of the Toshiba ER-4. The chapter appeared in The Historical Consumer: Consumption and Everyday Life in Japan, 1850-2000, edited by Penelope Francks and Janet Hunter (Palgrave Macmillan).

Yoshiko Nakano's book Where There are Asians, There are Rice Cookers (Hong Kong University Press, 2009) takes the story much further with her focus on the National (Panasonic) rice cooker and its adaptation and adoption around the world.

The Toshiba Science Museum, in Kawasaki, Japan, where we sourced our main image of the original ER-4, closed to the public in June. I do not know what the future holds for its collections, but luckily some of its Web pages have been archived to continue to help researchers like me.