A microwave is a kitchen appliance employing microwave radiation primarily to cook or heat food. Microwave ovens have revolutionized food preparation since their use became widespread in the 1970s. However many chefs find microwave ovens to be of limited usefulness because the Maillard reactions, cannot occur due to the temperature range. Cooking food with microwaves was discovered by Percy Spencer while building magnetrons for radar sets at Raytheon. He was working on active radar set when he noticed a strange sensation, and saw that a peanut candy bar he had in his pocket started to melt.
Although he was not the first to notice this phenomenon, as the holder of 120 patents, Spencer was no stranger to discovery and experiment, and realized what was happening. The radar had melted his candy bar with microwaves. The first food to be deliberately cooked with microwaves was popcorn, and the second was an egg which exploded after a short time. The new oven was shown at a trade show in Chicago, and helped begin a rapid growth of the market for home microwave ovens. Sales figures of 40,000 units for the US industry in 1970 grew to one million by 1975. Market penetration in Japan, which had learned to build less expensive units by re-engineering a cheaper magnetron, was more rapid.
A number of other companies joined into the domestic microwave market, for a time most systems were built by defense contractors, who were the most familiar with the magnetron. Litton was particularly well known in the restaurant business. By the late 1970s the technology had improved to the point where prices were falling rapidly. Formerly found only in large industrial applications, microwave ovens (often referred to as "microwaves") were increasingly becoming a standard fixture of most kitchens. The rapidly falling price of the microprocessor also helped by adding electronic controls to make the ovens easier to use. By the late 1980s they were almost universal in the US and had taken off in many other parts of the globe. Current estimates hold that nearly 95% of American households have a microwave.
Currently, the Chinese firm Galanz is the largest manufacturer of microwaves in the world. Annually the firm produces over 15 million appliances accounting for 40% of the global market.