Finally, after 5,000 years: PERFECT TOAST
The first electric toaster hit the market in 1909. You'd hardly realize it was a toaster by looking at it, though. Made by the General Electric Company, this odd-looking gadget consisted of bare wires wound around strips of mica (a kind of mineral). The toasters were completely open on the sides, lacking any kind of covering. Electricity heated the wires and the mica strips spread the heat evenly over the bread.
Only one side of the bread could be toasted at a time. You had to remember to turn over the bread to toast the other side halfway through. Lots of people forgot to.
By today's standards, these early electric toasters were not very convenient. They certainly weren't very safe. But they were an improvement over what you used to have to do: Put a slice of bread in a wire-and-tin contraption that sat on the burner of a coal stove. (First, heat up the stove.)
In 1919, Charles Strite, probably fed up with toast that was burned on one side and uncooked and cold on the other, patented the first spring-loaded pop-up toaster. Now people could grill both sides of their bread at once.
But it wasn't until 1927 that a mechanic from Stillwater, Minn., installed a clocklike mechanism on the toaster that would cut off the toaster's power and automatically eject the toasted bread with a forceful pop! The Toastmaster was born.
From 1922 to 1930, toaster sales tripled, from 400,000 to 1.2 million. An advertisement in The Saturday Evening Post exclaimed: "This amazing new invention makes perfect toast every time! Without turning! Without burning!" People were willing to spend $12.40 for a Toastmaster. It quickly outsold the $1 electric toaster model where you had to remember to pop up the toast yourself.
What was the driving force behind the toaster's popularity? The introduction of presliced bread. Before 1930, even commercial bakeries sold bread that you had to slice yourself. Hand-cut slices often varied in thickness and so didn't toast evenly. But mechanically sliced bread was perfect for the newfangled toasters.
Today, 9 out of 10 American homes have a toaster (more likely a toaster oven) on their kitchen counters. But did you know that the ancient Egyptians ate toast, too? In fact, they probably invented fluffy, yeast-risen bread about 2600 BC. Before that, bread was flat and tough.
Yeast bread was surely an accidental discovery. One theory is that yeast used for making ale in an ancient Egyptian brewery-bakery got into some bread dough by mistake. Another is that yeast spores got into the dough when bakers kneaded bread with their bare feet!
In any case, a lighter, fluffier bread was the result. Surprisingly, perhaps, yeast bread stayed fresh longer than flat bread did. To preserve it still more, Egyptians would toast slices to dry it out. Dried bread doesn't have much moisture in it, and moisture is what supports the growth of mold that spoils the bread. The Romans picked up this idea. They also used toasting to preserve bread. (In Latin, toastum means scorching or burning.)
HOW WORLD WAR II CHANGED POPCORN
Many times, a product invented with one use in mind turns out to be a smashing success in another field. Such is the case with the microwave oven. Today, almost 90 percent of American households have one.
The saga of the microwave oven's success began 54 years ago, when scientists were trying to find ways to make military radar more efficient.
Physicist Percy Spencer worked for the Raytheon Manufacturing Company, one of the world leaders in the production of radar equipment. In 1945, Dr. Spencer was experimenting with a magnetron. A magnetron is an electronic vacuum tube that generates extremely short radio waves, called microwaves. Magnetrons - invented by two Britons in 1940 - had been used in British radars during World War II.
Spencer was standing close to a magnetron when it was operating. Later (probably when he felt he needed a snack), he noticed that the chocolate bar he'd put in his pocket had melted into a warm glob. But he had not felt any heat. He knew that microwaves generate heat. He decided to experiment.
He put a handful of unpopped popcorn in a paper bag. Then he put the bag near the magnetron and turned it on. The kernels soon started to pop!
He was on to something. The Raytheon Company developed a cooking program and soon unveiled the Radar Range. The first microwave oven looked more like a refrigerator than the space-saving ones familiar today. It was big. It was awkward. It was expensive, too: $3,000. It was designed for use in hospitals and military canteens.
The first microwave designed for the home arrived in 1952, from the Tappan Company. In 1967, Amana sold the first countertop micro-wave oven for $495.
By the mid-1970s, microwave ovens had computer-chip technology that eventually made them cheaper, faster, and more compact.
How does a microwave oven work? All microwave ovens have a small magnetron to generate microwaves. The microwaves enter the oven's cooking compartment through a metal tube called a waveguide. A "stirrer" - a set of spinning metal fan blades - breaks up the microwaves to disperse them evenly throughout the cooking compartment.
Microwaves cause water molecules to vibrate millions of times a second. This vibration causes friction. Friction creates heat, and the heat is what cooks the food. Microwave ovens are faster than regular ovens because the microwaves create heat inside the food. In a regular oven, the heat penetrates the food from the outside.
You may have heard that microwave ovens cook food "from the inside out." This is not true. Microwaves penetrate only the first few centimeters of any substance. (Microwaves can penetrate only about 1-1/2 inches into meat, for example.) The heat must be conducted through the food to cook it thoroughly. That's why most microwave cooking instructions include the direction to let the food sit for a couple of minutes before serving. That's so the heat that the microwaves generated inside the food can finish cooking it.
SOURCES: 'How Products Are Made," Neil Schager, ed.; The New Illustrated Science and Invention Encyclopedia; "World of Invention,' Bridget Travers, ed.; 'Inventions and Discoveries,' published by Facts on File; 'Why Does Popcorn Pop? And 201 Other Fascinating Facts About Food,' by Don Voorhees; 'The Housewares Story,' by Earl Lifshey; 'Extraordinary Origins of Everyday Things,' by Charles Panati; The World Book Encyclopedia; 'Food in History, by Reay Tannahill.
(c) Copyright 1999. The Christian Science Publishing Society