When I’m reading novels of, say, the antebellum south and there’s a guy who goes around on a cart selling blocks of ice, how the heck did he get it? I mean, they didn’t have the fridge to rely on. Did they go way up north and cut blocks of ice and pack it in straw for the summer, or was there a way to manufacture ice at that time? I can’t figure this one out and have nowhere else to turn. Please help. –Terwiliger Paige, via e-mail
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To answer your question, yes, they cut ice up north in winter and packed it away for sale in the summer. You might guess that ice harvesting, as it was called, was an ancient trade. Not really. While stories of hauling snow down from the mountains for summer cooling date back to Roman times, the widespread practice of chilling food to preserve it, and thus the need for a reliable source of cold, is less than two centuries old.
Ice-harvesting technology was pretty basic. What kept harvested ice frozen was its sheer bulk: the more that could be tightly packed together, the longer it would stay cold. (Although the principles of mechanical refrigeration were generally understood in Ben Franklin’s day, practical application was decades away.) Ice houses, where stock could be stored year-round, had double outer walls separated by an insulator such as sawdust. An opening at the top vented the latent heat released by melting; water drained at the bottom lest it hasten thawing. Even so, the melt loss was huge–Wyeth guessed that in the early days 90 percent of the ice harvest disappeared before it could be sold. Better transportation, notably railroads, reduced losses, but even as of 1879, when the annual harvest was upward of eight million tons, about three million turned to water before it could reach market. Weather was another concern–an unseasonably warm winter could lead to an “ice famine” the following summer.
