How the humble household refrigerator changed the world — for better and for worse
"Once you can refrigerate food, you can manipulate not only time … but also space"
It's only taken 100 short years for the refrigerator to completely change humanity's relationship with food.
Many of us probably don't give our household refrigerator a second thought, but the modern global food system — from farming practices to worldwide shipping to supermarkets — simply couldn't exist without the ability to create cold on demand.
"It is a huge undertaking to sort of untangle how refrigeration has changed what we eat," said Nicola Twilley, a journalist and host of the podcast Gastropod. She's also the author of the forthcoming book The Birth of Cool, which tracks the rise of refrigeration and its global impacts.
"Today we take this technology so for granted that I think people think food isn't fresh or safe if it hasn't been refrigerated."
But the ability to keep things cold comes at a cost — both environmental and societal. And those costs are projected to grow as developing countries around the world continue to build up their own refrigeration infrastructure.
An icy American beginning
For thousands of years, people have known that colder temperatures will keep food edible for longer. Over the years, they've used all sorts of techniques to keep things cold — most of which involved storing naturally occurring ice.
The ancient Persians built giant stone domes and ventilation towers that took advantage of the region's arid climate to store ice, and provide air conditioning. The Romans and the ancient Chinese knew that adding saltpetre to water would rapidly drop its temperature — a technique that was later used in the Renaissance to popularize ice cream in Europe.
But the modern approach to refrigeration is a uniquely American invention, according to Jonathan Rees.
Rees, a professor of history at Colorado State University Pueblo and the author of three books on the history of refrigeration, traces the start of the modern refrigeration industry to Massachusetts merchant Frederic Tudor in 1806.
"He realized that the ice in New England that freezes every winter was itself a commodity," Rees said. "So he started selling it in the southern United States and the Caribbean, and he sent it as far away as India."
Tudor would start by giving away ice to bars for free. Patrons soon developed a taste for cold beverages that ice allowed — and Tudor would then start charging for his ice.
But it was a tricky business to be in. Harvesting the ice from frozen lakes and rivers was hard work, and much of the precious cargo would melt en route — and it was often contaminated with dirt, or even disease. With the demand for ice growing, the race was on to find a way to make ice with new technologies like electricity.
The principles behind the modern refrigerator are the result of hundreds of years of scientific investigation into the nature of matter and heat. In the early 20th century, that culminated in the development of the vapour compression refrigeration cycle.
For an explanation of how vapour compression refrigeration works, click on the video below:
Companies like General Electric, who stood to benefit from the increased demand for electrification in homes, threw their names behind the effort to perfect the technology.
By 1927, Rees said, vapour compression refrigerators had more or less been perfected.
"There are more bells and whistles on your modern refrigerator — you know, like the light inside," Rees said. "But in terms of keeping food cold, the only difference between it and the modern refrigerator is that it's smaller."
The birth of the cold chain
The ability to keep things cold indefinitely had massive and almost immediate impacts on North Americans' relationship with food. Meat and produce could now be kept cold from its initial harvest all the way to consumers' kitchens. The infrastructure that allows this — warehouses, shipping containers, supermarkets and home refrigerators — is known collectively as the "cold chain," and it completely overhauled the way food was produced and brought to market.
"Once you can refrigerate food, you can manipulate not only time, so how much time you have to consume it; but also space, so how far away that food can be from a consumer and still make it to them," said Twilley.
Produce grown in California could now be shipped across the continent with ease. Once-exotic fruits like bananas became commonplace, and seasonal foods like apples and eggs could be stored in refrigerated warehouses to be eaten year-round — though flavour was sacrificed in the process.
"One of my favourite examples of this is iceberg lettuce," said Rees.
"[It was] invented in the first decade of the 20th century … solely because it can stand up to ice when it's being shipped from California to the rest of the country. So it is a product that's bred entirely for refrigeration as opposed to taste."
Changing diets…
As car-dependent suburbs grew across the continent following the Second World War, refrigeration-powered supermarkets supplanted local markets. Combined with the ability to keep food cold at home, the North American diet began to change considerably.
"When you look at statistics overall, people do eat more fresh fruit now than they did [before refrigeration]." Twilley said. "People eat more meat than they did, and dairy."
But she also notes that consumption of fermented foods decreased, since it was no longer an essential preservation technique — and there is mounting scientific evidence of the health benefits of fermented foods.
"It's a really interesting and really mixed bag and when you … try to tease out, was this a net benefit or not to our health," she said. "That is extremely complicated and very unresolved."
Twilley has reported from countries like China and Rwanda about their efforts to create American-style cold chains of their own, where many of the same changes are starting to play out.
"You can see the shift in diet to prepared foods, frozen foods, convenience foods, the rise of branding of food," she said. "Once you can store it and ship it, it can become a brand."
… and a changing climate
One of the often cited benefits of refrigeration is a reduction of food waste — an important climate change goal, according to Twilley.
"Food waste is a huge source of methane, especially when it's buried in landfill rather than being composted," she said.
But it's not clear that refrigeration actually reduces food waste overall. According to her research, about 40 per cent of food is wasted before it gets to the market in the developing world — that is, in countries without established cold chains. But in countries that do have those cold chains, households throw away between 30 and 40 per cent of their food.
"Refrigeration seems to sort of just switch where it happens, not prevent it," Twilley said.
Vapour compression technology itself has also come with another unintended consequence: the harmful effects of its refrigerants. Scientists like Drew Lilley, a researcher at Lawrence Berkeley National Labs, are working on ways to minimize their impact — or replace vapour compression entirely.
"There's a long history of the destructiveness of refrigerants both environmentally and to human health," Lilley said. "We've been using them for 100 years and we still have not found a suitable replacement."
Early refrigerators used ammonia as their refrigerant — and many larger systems today, such as ice rinks, still do. The highly poisonous gas was eventually replaced with chlorofluorocarbons (CFCs), also known under the trade name Freon. CFCs were banned in 1987 after they were found to be damaging the ozone layer.
Modern refrigerators now use hydrofluorocarbons (HFCs), but some varieties have as much as 10,000 times the atmospheric warming impact of carbon dioxide. Many governments are now looking to phase out HFCs, but there's no clear agreement on what to replace them with.
Lilley is looking into other possibilities entirely. For his graduate thesis, he and his team outlined a process they call "ionocaloric cooling." Instead of using the energy from a liquid-to-gas transition, his system modulates the concentration of salt ions in a solution to change its melting point. With no vapours involved, there's no potential for dangerous gas leaks.
In places with established cold chains, like North America and Europe, Twilley sees an opportunity for governments to take stronger regulatory stances — and even implement national cooling strategies, as in places just starting to build them, like Asia and Africa.
"It has been left to private industry forever and seen as a private business outside of food safety concerns, but I think it is a piece of national infrastructure," she said.
"We're reliant on it for our food supply, [and] citizens surely have an interest in that. If it fails or it's not resilient or it's not able to keep pace with climate change, then we all lose."