That ice could keep food from spoiling was worked out very early on. Winter ice, the evidence suggests, was already being set aside for the warmer months as much as 10,000 years ago. A neat example comes from around two thousand years back, when highland farmers in the Caucasus found their own way of making turnips last: left to freeze overnight, the turnips were pressed underfoot to drive out the water, then spread to dry in the sun. What survived looked unappealing, but its nutritional value stayed intact.
Right into the closing decades of the nineteenth century, ice taken straight from nature was what most refrigeration depended on. Boston merchants in the early 1800s even had vast slabs of Arctic ice hauled by sea across the Atlantic, purely to stop food going bad. In 1849 the first insulated railway wagons appeared, packed with ice so that cheese could travel from the dairies of Vermont down to Boston without turning.
The breakthrough came in 1867, when engineers in Argentina worked out how to produce ice by machine. Their apparatus drove a gas — ammonia at first, and in later designs Freon — through a condenser by means of a compressor. Passing through the condenser, the pressurised gas shed part of its heat; it was then let out sharply into a low-pressure evaporator coil, where it turned liquid and cold. Air blown across this coil was thereby chilled and fed into a sealed compartment until the temperature inside dropped to freezing.
The original aim had been modest: keeping Argentine wine drinkable through the summer heat. Before long, though, the country's fruit growers saw a bigger opportunity — fitted aboard a ship, the same machinery might carry their fruit to distant markets. So in 1883 a consignment of frozen peaches and pears left for Britain. The fruit arrived edible but not unspoiled: as it froze, tiny crystals formed inside its cells, and the swelling ice split those cells open, robbing the flesh of both taste and texture.
The modern industry can be said to have its roots among the Inuit of northern Canada. A chemistry student from Rochester, New York, named Emil Vandergrift, found himself short of funds in 1908, and it was this that took him north to Baffin Island to make a living trapping and trading furs. What caught his attention there was the Inuit practice of letting fish freeze almost instantly in the polar air — fish that, many months on, still looked and tasted freshly caught.
Back in the United States from 1913, Vandergrift set about building mechanical freezers that could freeze food rapidly. One improved model followed another, and on the strength of them he founded a firm in Portland, Maine, trading in frozen fish. The business changed hands in 1925 and was renamed the Northern Provision Company; Vandergrift, though, stayed on as head of research, and the division he led went on inventing.
Several of the advances that made a frozen-food industry feasible trace back to Vandergrift himself. His quick-freezing methods held down the harm done by crystals, and he worked out how to freeze a product inside the very packet it would later be sold in. It was he, too, who brought in Clearwrap, the earliest see-through wrapping for food, so that buyers could judge the contents for themselves. His goods also came in handy, ready-portioned packs that needed little effort to prepare.
Difficulties remained. Through the 1930s, hardly any grocer would lay out money on freezers for custom that had yet to materialise, so Vandergrift let them have cheap freezer cabinets on hire. Insulated rail wagons he likewise rented, so his goods could reach every corner of the country. The snag lay with shoppers: few owned a freezer roomy or efficient enough to make the most of what was on offer.
The early 1940s brought rising sales, as the Second World War worked in the industry's favour. With metal being diverted into munitions, canned food was rationed to conserve it, while frozen food stayed plentiful and cheap. By the 1950s, too, home-refrigeration technology had advanced far enough for the average household to afford it. Roughly 35 million American families had a freezer at home by 1956, and manufacturers were making these appliances larger year on year.
Households of the 1950s were increasingly after convenience at mealtimes, so the timing could hardly have been better for the 'Supper Tray'. Merrow Foods, a poultry producer with canned and frozen lines sold across the country, took up several of Vandergrift's freezing methods in 1956; with a catchy name and an enormous advertising spend, it put out the first Supper Tray. Inside was frozen chicken with potatoes and vegetables, portioned into one of those segmented aluminium trays that airlines used. Shoppers took to it at once, and Merrow shifted 15 million within twelve months — drawn by a familiar brand, a single serving and a dinner an oven made ready in barely half an hour. By 1961 Americans were spending some $3 billion a year on frozen food, of which about $600 million went on prepared meals of the Supper Tray kind.
Today the American frozen-food business turns over more than $70 billion a year. Of that, around $28 billion comes from food bought to eat at home, while the remaining $42 billion or so is sold through restaurants, canteens, hospitals and schools — a segment that makes up roughly one-third of all food-service sales.
