The Engines of Our Ingenuity 3355: Tin Cans

0:00This is the engines of our ingenuity made possible by the friends of KUHF Houston. Today, let us make tin cans. The University of Houston presents this series about the machines that make our civilization run and the people who's ingenuity created them. Long ago, when I spent some time in the U.S. Army, we dreaded days when we had to eat sea rations, sea for combat. These were field rations meant for troops out of reach of a mess hall. Tin cans full of artificially flavored foods. I should qualify that tin can remark, since tin cans are generally steel coated with tin. Late 18th century Dutch had learned that tin containers were food-friendly. They'd been packing fish and containers made of tin's wrought iron.

1:00Then Napoleon's armies, like armies ever since, had to be fed in the field. So, a French confectioner showed how to provide him with bottled food. Soon after, another French inventor patented tin can food preservation that was sealed far more completely than Dutch tins had been, but manufacturing issues kept sealed tin cans from reaching the general public until the late 19th century. Even then, it took the need to feed combat troops in World War I to finally make practical tin cans that we would recognize today. Today tin cans are ubiquitous, but they're not free of problems. Many offer foods that are heavy in salts and salt. Is it easy means for preventing spoilage? Then there's the problem of opening tin cans, and here we faced a whole new set of issues. A well-sealed can took tools to open. At first, one was at the mercy of domestic tools, chisels, hammers, and such.

2:04Eventually, canned manufacturers offered help, like cans with twist keys. The first-hand can opener followed in the mid-19th century, they took three forms. One was the lever type that lets us puncture a can, then work our way around the rim, levering the cut to half inch at a time. The other was a key turned rotating wheel, which, once it had punctured one spot, could continue cutting all the way around. Finally, the church key type. It just makes a single triangular hole in a can full of liquid. Then, starting in 1931, the first electric can opener hit the market, and it's been followed by a dizzying series of improvements ever since. I use one now and then, but I'm not shy about picking up my old-fashioned mechanical ones in its place. And I'm back to those accursed sea-rations. You don't want soldiers searching for a can opener on a battlefield,

3:06so we were equipped with a tiny specialized can opener that rode around our neck next to our dog tags. Well, I find myself approaching lunchtime, and once again I face that ultimate decision. Should I cook a proper meal, or should I open a can? I really won't know of the answer until I reach the kitchen. I'm John Leanhardt at the University of Houston, where we're interested in the way inventive minds work.