"Cooler Corn! For when you've got a lot of people who want corn. Perfect for tailgating or BBQs."
Summer is here for a lot of us in the Northern Hemisphere, and I've gotten a lot of people asking me about cooler corn, or if you can safely cook corn on the cob in your ice chest or cooler. The idea is an interesting one; instead of heating up your house in the summer to get corn on the cob, or if you have to cook a lot for a BBQ or cook out, simply add it to a cooler, cover with boiling water and let it cook in the cooler. This idea is still highly debated among some. Does it work? Yes, it really does. But the problems that bring this into question is: can the heat leach chemicals or damage the ice chest? For the most part, yes.
It seems the original image and idea came from a post over at the blogs on Bon Appetit. However, the original post didn't bring up any of the concerns that make this a bad idea. (source)
You see, most home coolers are made with PVC and other various plastics which often times contains BPA and other chemicals not made to be ingested. Coolers, when used properly, offer little risks of leaching chemicals into food since most people store their foods on ice, and often times in containers within the cooler. Once the plastic itself is heated though, the chemicals in the plastic begin to break down and leach into the water. BPA is legal in the US for use in plastics, but due to the public concern of the possible link to serious health risks, more and more companies are no longer using it in plastic made for food use. Chances are though, your cooler isn't one of them. And there are other chemicals in plastic besides BPA to worry about.
On top of that, certain coolers have been known to warp once exposed to high heat from the boiling water. I found a great forum post about this over at Home Brew Talks where someone was kind enough to actually send shavings of his coolers to be anylist in a lab. The results? The inside white plastic starts to melt at 212°F (100°C), which is boiling point for water. (source)
So my conclusion? I'd honestly leave this one as a "last case scenario" idea. It does work, but you run a really good chance of ruining your cooler or have chemicals you really don't want leaching into the water. Not a single cooler manufacturer backs this suggestion, as every cooler is meant to cool items -- it's in the name of the product. However, this does beg the question - if not in your cooler, than what? I'm rather curious to see if this sort of thing would work in a stockpot with lid. Corn can cook quickly and easily, so I imagine any large basin with lid would work. Just make sure it's food grade material and preferably not plastic.