Food is delicious, not to mention kind of important for life. But food also goes bad, so humans have invented many ways to preserve it to eat later or far from where it was harvested. Some of these methods require unhealthy chemicals or degrade the food's nutritional value. But luckily, freezing can preserve food with most of its nutrients, well, frozen in place.
The important part is that most chemical and biological processes run slower at lower temperatures, which means that if you cool food a lot, enzymes and bacteria and fungi in the food get too cold to decompose it. That's why food lasts longer in the freezer than in the fridge than on the counter. Freezing, however, wasn't always an easy task, especially before fridges were invented. It's not that freezing food is a new idea—I mean, people who live in cold places have done it by default for thousands of years. But things got messy when we started creating artificial winter to freeze food in warmer climates.
Early freezers were basically rooms full of salty ice, which, while they could freeze food, took many hours or even days to do so. A slow freeze gives fluid within cells the time to stack up into big ice crystals. Since water expands when it freezes, the sharp edges of these crystals poke holes through the walls of the cells, and when the food thaws, the fluid leaks out. Gross! Even grosser? Birds' eyes. Clarence Birdseye, to be precise.
An American entrepreneur who lived in Arctic Canada in the nineteen-teens, Birdseye noticed that when Inuit people went ice fishing in minus-40 degree windy conditions, their catch froze almost immediately. When cooked later, the fish tasted fresh. Birdseye realized that the Arctic frozen foods were tasty because they froze quickly and formed smaller ice crystals that didn't damage the cells. Inspired, he went on to develop a process to quickly freeze food by pressing small packages between metal plates chilled to 40 below zero. Combined with clever marketing, this allowed Birdseye to bring Arctic winter to the rest of the world and to almost single-handedly jump-start the modern market for frozen foods.
一位 1913 至 1919 年間居住在加拿大極地的美國創業家，Birdseye 他注意到當因紐特人在負四十度颳風的情況下去冰釣時，他們的漁獲幾乎是馬上結凍。過一陣子被拿來煮時，魚嚐起來很新鮮。Birdseye 發現北極冷凍食物很好吃，因為它們快速結凍並形成不會破壞細胞的較小冰晶。受到啟發，他開始研發能快速冷凍食物的方法，那冷凍方法是靠將一包包小包裹塞進冷凍到零下四十度的金屬板間。結合聰明的行銷，這讓 Birdseye 得以將北極的冬天帶到世界其它地方，且幾乎隻手開啟了現代冷凍食物市場。
You probably even have your own freezer, a marvelous device cold enough to quick-freeze almost any food you put in it. In other words, the North Pole—in your kitchen.