The Forgotten Industry of Ice

In the winter of 1806, a young Boston merchant named Frederic Tudor loaded one hundred and thirty tons of ice harvested from a Massachusetts pond onto a brig bound for the French colony of Martinique. The voyage was a disaster: the ice arrived in good condition, but Tudor had nowhere to store it, no buyers prepared to pay what he asked, and no infrastructure for a product that nobody on the island had imagined wanting. He lost most of his investment. He was twenty-three years old, and he spent the next three decades turning ice into one of the largest industries of nineteenth-century New England.

The ice trade is one of those vanished industries that, while it lasted, looked permanent. At its peak around 1880, the United States was harvesting more than ten million tons of natural ice each year. Boston ice was shipped to Calcutta, Rio de Janeiro, Hong Kong, and London. Norwegian ice fed the British market. Ice harvesting was the third-largest industry in the state of Maine, employing tens of thousands of seasonal workers. The infrastructure was massive: ice houses the size of cathedrals, dedicated rail spurs, sawdust-insulated ships, urban delivery networks of horse-drawn wagons. Then, within a few decades, the entire industry vanished, displaced by mechanical refrigeration. By 1930 the natural ice trade was a curiosity. Today the only people who know it existed are local historians and the occasional reader of nineteenth-century economic statistics.

How you actually harvested ice

The mechanics of ice harvesting are worth knowing because they are not what most modern readers picture. The process required ice that was thick (eight inches or more), clear (free of trapped air bubbles, which made it cloudy and structurally weaker), and flat (the surface had to be plowed clean of snow regularly through the winter to allow uniform thickening).

The harvest itself happened over a window of two to four weeks in midwinter, when the ice was at peak thickness but before any thaw began. Crews would mark the ice into a grid using horse-drawn ice plows that scored grooves about an inch deep. The grooved blocks were then sawed through manually with long crosscut saws, broken free with iron bars, and floated in channels of open water toward the ice house, where they were lifted out by elevator and stacked.

The ice house was the technological key to the whole industry. A well-designed ice house could store summer-needed ice from a winter harvest with losses of only ten or fifteen percent. The walls were double-skinned with sawdust packed between them, and sometimes triple-skinned with hay outer insulation. The floor sloped to drain meltwater away from the stack. The blocks were packed tight with sawdust filling every gap. A large urban ice house held thousands of tons of ice and looked, from outside, like an industrial warehouse with no windows.

The shipping innovation that Tudor pioneered was the use of sawdust as insulation in ship holds. Pine sawdust, a near-zero-cost waste product of New England's lumber industry, turned out to be one of the best insulators available, and it allowed ice to be shipped to the tropics with losses of only twenty to thirty percent over voyages of months. The economics were extraordinary: ice cost almost nothing to harvest (the raw material was free, the labor was seasonal), almost nothing to transport (the sawdust was waste, the freight was filling otherwise empty holds), and sold for substantial prices in markets that had never seen ice before.

What ice changed

The cultural and economic effects of cheap ice were larger than they appear. In the 1830s, ice was a luxury. By the 1860s, urban Americans took it for granted, and the cultural patterns that emerged are still with us.

The American taste for cold drinks dates to the ice age. Europeans drank room-temperature water, beer, wine. Americans, once ice was cheap, drank everything iced, and the preference embedded itself culturally so deeply that "American-style" cold drinks remain a recognizable category internationally. The fact that you ask for "water with ice" by default in the United States and "still water at room temperature" by default in Italy is partly an inheritance from the nineteenth-century ice trade.

The American beef industry was made possible by ice. Cattle were raised in Texas and processed in Chicago and shipped, refrigerated by ice, to markets in the East. Without the cold chain, beef had to be raised near where it was eaten or salted into preservation. With the cold chain, you could ship fresh meat across a continent. The Chicago packing houses that ran on ice harvested from the Great Lakes were the basis of American agricultural-industrial integration.

The fish trade similarly transformed. Cod from the Grand Banks could be brought fresh to inland cities. Oysters from the Chesapeake reached Cincinnati. The geography of fresh seafood expanded by an order of magnitude.

Domestic refrigeration spread before mechanical refrigerators existed. The icebox, a wooden cabinet with an insulated chamber that held a block of ice replaced every few days by an iceman, was standard middle-class equipment from the 1860s onward. The pattern of daily delivery (the iceman came on a schedule, like the milkman) created the urban infrastructure that delivery services still inherit. The modern grocery delivery business is, structurally, the iceman's route.

The collapse

The collapse of the natural ice industry was as fast as the industry's rise. The trigger was mechanical refrigeration, but the timing depended on a cluster of pressures that hit simultaneously.

Mechanical refrigeration was first practical in industrial settings in the 1870s. The German engineer Carl von Linde built the first commercially viable ammonia-compression refrigeration plant in 1873, and the technology spread quickly to breweries, meatpacking houses, and dairies. By the 1890s, mechanical refrigeration was cheaper than natural ice for any continuous industrial use. Brewers stopped buying ice and started running their own refrigeration plants.

The natural ice industry might still have survived for domestic use, but two pressures killed it there too. The first was warm winters: the late nineteenth century saw a series of mild winters in the New York and New England areas, and ice harvests failed. The 1880 Hudson River harvest was a third of normal; the 1890 harvest was less than half. Ice prices spiked, customers switched to the still-novel alternative of mechanical ice plants, and the customers did not switch back.

The second pressure was urban water pollution. As cities grew and industrial waste poured into the rivers from which ice was harvested, the public health argument against natural ice grew stronger. The 1902 typhoid outbreak traced to ice from the Hudson River was the inflection point: thereafter, every newspaper article about an ice-harvest was paired with an article about contamination. Mechanical ice, made from purified water under controlled conditions, did not have this problem.

By 1910, mechanical ice had majority market share in domestic use. By 1920, it had nearly all of it. By 1930, the natural ice trade was over. The infrastructure was scrapped or repurposed. Ice houses became warehouses or were torn down. The seasonal labor force aged out and was not replaced. The ships were converted or sold. Within thirty years, an industry that had employed hundreds of thousands and reshaped global trade flows simply ceased to exist.

What the ice trade tells us

What is striking about the natural ice industry is how completely it has been forgotten. The textbooks of nineteenth-century American economic history give it less space than the rise of the railroads or the steel industry, and the popular memory has retained almost nothing. There are no Ken Burns documentaries about the ice trade. The Tudor warehouse in Charlestown is a residential building with a small plaque. The industry that put ice in every American home is more obscure than the industry that put a Coca-Cola in every American hand, despite being older and arguably more transformative.

Part of the answer is that the ice trade did not produce surviving institutions. The Tudor Ice Company is gone. The Knickerbocker Ice Company is gone. The companies that displaced them are also gone (consolidation, bankruptcies, mergers into larger refrigeration firms that now make different products). There is no living organization carrying the ice industry's memory forward.

Another part is that the technologies of the trade (saws, sawdust insulation, ice plows) have no living descendants. The skills and knowledge that lived in the heads of ice harvesters were not passed on, because there was no ice industry left to pass them on to. We know how to harvest ice from a frozen pond at industrial scale only from photographs, written records, and a few preservation efforts.

The pattern repeats with other vanished industries: whaling and the lighting infrastructure it supplied, leech-collecting and medical bloodletting, the human telephone-switchboard operators, the icemen who delivered to your door. Each, while it existed, looked permanent. Each was displaced by a more efficient technology. The forgetting is not malicious, but it is total. We retain a few cultural artifacts (the cocktail with ice, the iceman cometh, the metaphor of the iceman) and almost nothing else.

The cautionary note is that some of the industries we currently take for granted will look, in a hundred years, as obsolete as the ice trade. Which ones is hard to predict, because the technologies that displace existing industries usually look unimpressive at the moment they begin displacing. Mechanical refrigeration in 1870 was an industrial curiosity that consumed huge amounts of fuel to produce ice that the natural-ice industry made for free. By 1920 the curiosity had won. The pattern is not new.