Never mind the cold outdoors, it's the temperature inside that makes a difference when we're cooking — inside the refrigerator, that is (which optimally will be set at 39 degrees).

That chilly spot that keeps our perishables at their best for mealtime seems to disappear into the kitchen woodwork unless it's noisy or not working.

That was the case for me until I was without refrigeration for six weeks last summer. After a move to a new home, I took my time exploring options (because how often do I buy a refrigerator?).

It took only a few frozen dinners, grabbed from the corner store nightly, before my inner lightbulb switched on: Where would we be without refrigeration? And then, the more profound realization thwacked me on the head: Refrigeration changed the world.

And it's not only because it kept our food cold.

Long before there was refrigeration, cooks found ways to preserve what would otherwise be perishable by pickling, potting, drying or salting it (and later, canning) — all methods that changed the food's flavor and texture. And all are techniques still relied on around the world.

As for the use of ice, that dates back to at least 1100 B.C., based on underground icehouses in China. Jonathan Rees, in "Refrigeration Nation," notes that donkeys carted ice from the Alps to the Roman emperors. Snow was shipped by boat to Istanbul in the 16th century. For the common people at home, depending on where they lived, they may have harvested ice from lakes and streams or frozen it in pans when the temperature dropped.

But our story really begins in the 19th century, when ice was first cut from lakes in New England for commercial use, and transported as far away as India.

It wasn't enough to get ice from here to there, remarkable as that was. Those on the other end had to know what to do with it. Rees tells the story of one of the first shipments of ice to Martinique, where a customer brought a chunk home and left it outdoors in the sun. Talk about educating your customers.

And that's really the story of refrigeration: Many stops along the "chain of cold" had to handle chilled food correctly for the process to be viable.

Once there was a reliable source of year-round ice, home cooks depended on the icebox to keep perishable foods from spoiling too fast. Ice was delivered often, but the temperatures within the icebox were unpredictable at best, and were never as cold as our refrigerators are today.

The appliance we have come to depend on didn't arrive on the scene in many homes until 1925 to 1945, a remarkably short span for an innovation of that sort to be accepted. More than 80 percent of U.S. kitchens had one by the end of World War II.

The early refrigerator was considerably smaller (holding 8.6 cubic feet of food; today it's 18 to 26 cubic feet) and without a freezer compartment, though the space by the compressor was cold enough to produce ice. By the '50s, virtually every American home had one.

Combination freezer-refrigerators were the natural next step, and some cooks rented freezer locker space in warehouses. The stand-alone chest freezer didn't appear until the refrigerator market was saturated.

The novelty of the cold contraption took up an early TV episode of "I Love Lucy" when Lucy and Ethel buy an inexpensive meat freezer and fill it with expensive meat. Craziness ensues and, of course, Lucy gets locked in the freezer.

Not until after World War II did frozen food find a place in the home kitchen, though it had been around since the 1920s when Clarence Birds­eye realized that freezing fish fast meant its texture wouldn't change. He later applied that concept to fruits and vegetables. But the product needed enough consumers with freezers before there was a sizable market for it.

Refrigeration changed our lives in ways big and small.

• Until then, dinner tables relied primarily on local foods, though dry goods (flour, tea, spices) had been shipped for years. Once refrigerated railroad cars and trucks were available, perishable food could be transported across the nation and beyond. Two Minnesotans — Frederick McKinley Jones and Joseph Numero, who went on to form Thermo King Corp. — began developing refrigeration units in the late 1930s that revolutionized the movement of perishable food. California iceberg lettuce found a place on the Minnesota table.

• Transportation of food added a great variety to the American diet, and that included greater choices for the poor.

• Food prices dropped due to availability, which resulted in improved nutrition for people of all classes.

• Mealtime options expanded beyond seasonal foods. Fresh food began to be available year-round.

• Small markets began to be edged out by supermarkets, which could offer food in larger quantities.

• Refrigerated cases in supermarkets meant you could buy pre-cut meat and no longer had to go to a butcher's shop.

• There was less food waste because spoilage was under better control.

• Mealtime was more convenient for the cook, with less shopping necessary.

• The prevention of spoilage was what prompted refrigeration, but today it's recognized as an important part of food safety because it suppresses the growth of food-borne bacteria, says Craig Hedberg, a professor in the School of Public Health at the University of Minnesota.

And along the way, our palates evolved as they always do when new flavors and textures are introduced.

"Refrigeration raised the expectations of what food would taste like. People no longer expected that food would taste old, but would taste fresh," said Tracey Deutsch, an associate professor of history at the University of Minnesota.

Dinner would never be the same.

Follow Lee Svitak Dean on Twitter: @StribTaste