Chemists calculated that it takes no more than 11 pounds of potatoes to make a pair of galoshes. They extract alcohol from the tubers, refine it, and convert it into rubber. From that rubber, they can make galoshes fairly straightforwardly.
But when potato starch ferments it produces not only alcohol but also carbon dioxide. In the past that gas was vented into the air. Now carbon dioxide is used to make dry ice. Dry ice is colder than ordinary ice and has a neat trick: it doesn’t melt — it sublimates, turning directly into gas. One moment there’s a chunk of ice, the next it’s gone.
There are plenty of amusing stories about dry ice. One such incident took place in a restaurant in New York City.
A young man sat at a table and ordered a bowl of soup. The waiter brought it and stepped away to help another customer. Suddenly the man started banging his spoon against the bowl. The waiter rushed back.
“What did you bring me?” the young man asked. “This isn’t soup; it’s a block of ice!”
The waiter couldn’t believe his eyes: there was indeed ice in the bowl, with pieces of meat, circles of fat, and pasta frozen inside. Trying to avoid drawing attention from other diners, the waiter took the bowl of ice away and brought back a fresh bowl of hot, aromatic soup. But as soon as he stepped away, the man called him back again: the new soup had frozen solid.
This happened several times until the unusual occurrence caught the attention of all the patrons.
The man worked at a factory that had recently started producing dry ice from carbon dioxide in America. He was demonstrating the process on behalf of his employers in a restaurant frequented by prominent businessmen who might be interested in the product’s properties.
Dry ice reaches temperatures found only in the coldest places on Earth — about minus 109 degrees Fahrenheit. With a small specialized setup, it can be produced anywhere, at any time of the year, and in any quantity.
