Somehow the humble microwave oven always appears to be a device from the near future, but the truth is, it’s been irradiating our food into readiness for decades now. So long in fact, that if it were a person it would be pulling a pension already. We decided to take a look at the history of this device which changed kitchens forever despite being invented by my mistake.
The magnetron, the device which serves as the core of almost any microwave oven, actually dates back to the late 1930s, when British physicists figured out how to use a vacuum tube to control and emit high frequency radiation (i.e. microwaves) over short distances – and reduce the size so that these cavity magnetrons could be installed on vehicles and submarines
This technology would first find use as the means to power radar for British and American forces during the second world war – by emitting microwaves and monitoring their reflections, troops could detect where other ships at sea lay. But the magnetron would soon find a new purpose on dry land, just months after the war’s end.
Soon after the war ended, an engineer with defence giant Raytheon by the name of Percy Spencer stumbled across this purpose. The contractor had been granted licence to mass produce the magnetrons, and it was one of these that caused Spencer’s chocolate bar to melt in his pocket while he worked, an unexpected side effect of his experiments. Cottoning on to this previously unnoticed ability of microwaves, he attempted to cook popcorn, then an egg, which promptly exploded in the face of a technician.
Still, the concept seemed promising, and he got to work on turning the technology into a cooker, filing a patent in October of that year. Spencer, who earned over 300 patents in the course of his career, was given a grant of just $2 for this breakthrough, perhaps his most important.
Just two years later, the first commercial microwave oven was ready. Raytheon’s “Radarange” microwave oven was a hulk, closer in size to a modern double fridge freezer combo than today’s counter-top microwaves, standing almost six feet tall, clocking in at 340 kilograms and ringing up $5,000 – or more than £30,000 today. If you couldn’t afford one however, you could see how the technology worked by visiting New York’s Grand Central Terminal, where a “Speedy Weeny” vending machine shot out microwaved frankfurters on demand.
Raytheon created the microwave oven, but it was Sharp that was the first to mass produce the humble super heater. The company began work on the R-10, Japan’s first microwave oven, in 1961, with the first units shipping the following year. The size of a traditional convection oven, it was meant for commercial businesses, but Sharp was confident that someday microwave ovens would be a staple appliance in homes, and set about creating awareness and a customer base.
In 1967, Raytheon subsidiary Amana released the first Radarange microwave oven designed – and priced – for domestic use. The 100V oven would sit on the kitchen counter, and retailed for just $500, a bargain compared to the original jukebox sized sizzler. Importantly, it would set the standard for decades to come, employing a more compact, squat and shallow chamber for cooking – much like today’s models, in other words.
The “science oven” Jennifer Lawrence’s character accidentally destroys in American Hustle might have looked like a novelty, but by the mid-1970s the microwave oven was already selling rapidly in both Japan and America. In fact, by 1975 sales of microwave ovens had already eclipsed those of conventional gas ovens.
On both sides of the Pacific, Spencer’s invention was providing the cooks in every home with a convenient way to quickly heat, reheat and even defrost food: one study at the time found that 17 per cent of families in Japan were using a microwave oven by this point.
For almost half a century, microwave ovens provided an easy way to quickly heat up food, but they still had drawbacks – they were unable to brown food, for instance, meaning if you wanted that tasty, just-seared aroma you’d have to be patient. Then the convection microwave arrived. A combination of both convection and microwave ovens, it was the best of both worlds, quickly heating up food while delivering that authentic browning effect at the same time. Today, convection microwaves are commonplace, and most domestic models use technologies that draw from them – many of Sharp’s current models for instance offer both built in convection ovens and top grills.
While microwave ovens have offered different cooking operations since the beginning, until only relatively recently could you actually alter the power at which they cooked. If you wanted something cooked on half power, they would simply toggle full power on and off for half the time. The arrival of inverter technology changed this, providing a method to actually decrease the power at which an oven cooked – cooking (and especially defrosting) food much more reliably.
After more than sixty years of faithful service, the magnetron could finally get its chance to retire: just two years ago, Chinese manufacturer Midea revealed its revolutionary plan for the solid state microwave. No vacuum tube, in fact, no moving parts: the prototype oven is simply able to emit radiation at the standard 2450MHz frequency required of all microwave ovens. Think of it as going from a PC with a whirring, mechanical hard drive to a tablet with speedy solid state storage – this is the jump we could soon be seeing in the future: meaner, faster, more efficient and smaller.
Humans Invent is an online space dedicated to celebrating innovation, craftsmanship and design fuelled by our most natural instinct – the pursuit of invention to help solve a human need. You can read their original article here.