How do they keep soda pop in outdoor vending machines from freezing in winter?

Dear Cecil:

Here in northern Illinois and southern Wisconsin I see a lot of soda pop machines that are outside all year round. During the winter we have streaks of cold weather where the temperature can be below freezing for weeks at a time. What happens to the pop in these machines? Does it freeze and break the cans or what?

Cecil replies:

This is not the thing that amazes me, Scott. After all, the optimal temperature for an ice-cold Coke is, if not ice-cold, pretty close to it — 38 degrees Fahrenheit. Pop machine manufacturers use various active and passive technologies to keep the contents from freezing altogether, ranging from insulation to conserve the heat generated by the machine’s electrical equipment to actual heaters. What I can’t get over is that people in Wisconsin or Norway or wherever will buy and presumably drink an ice-cold Coke in the middle of winter. It’s supposed to be the pause that refreshes, not that gives you hypothermia.

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