Those quick thaw defrosting trays are also good at taking money directly out of your wallet. What they are is a remarkable new high-tech, space-age miracle called a slab of metal.
Of all types of materials, metals are the best conductors of heat. So if you put your frozen hamburger on a slab of metal, the metal will dutifully conduct heat from the warm room into the cold hamburger, and it thaws in a relatively short time. That’s all there is to it.
It’s no more remarkable than the fact that any piece of metal feels cold to you (“cold steel”) because it conducts heat from your warm skin into the relatively cooler room. Leaving frozen food out in the air is the slowest way to thaw it, because air is just about the worst heat conductor around.
The “miraculous, all-natural” defrosting tray, made of “an advanced, superconductive alloy,” is nothing but a slab of aluminum. Aluminum conducts heat more than half as well as silver, which is the best conductor of all. Aluminum sells for about forty cents a pound, but you’ll pay fifteen to twenty bucks for two pounds of it in the form of that miraculous defrosting slab.
Oh, yes, one little detail. The instructions tell you to “condition” the slab by running hot water over it for a minute or so before using it each time, and again half-way through the thawing process. Sounds like cheating to me.
But what hooks many people is the astounding demonstration that the slab manufacturers challenge you to try: Put an ice cube on the miracle slab and another one on the kitchen counter beside it. Lo and behold! The one on the! slab melts quickly, while the one on the counter just sits there looking embarrassed. It really works.
What’s going on? Well, the people selling the slabs are pretty sure that your kitchen counter is made of plastic laminate, tile, or wood, materials that are such poor conductors of heat that they’re actually heat insulators. Naturally, the ice won’t melt nearly as fast on an insulator as it will on a metal heat conductor. But try the demonstration this way: Put one ice cube on the slab and the other one on an unheated, heavy aluminum frying pan beside it. You’ll find that they melt in exactly the same amount of time.
You can thaw your frozen food quickly by unwrapping it and placing it on an unheated, heavy frying pan, or for even faster service, on one that you’ve warmed with hot water (not on the stove). Except for the cast-iron ones, frying pans are deliberately made to be good conductors of heat, so any heavy pan other than iron will work as well as those “miracle” trays. (Iron conducts heat only about one-third as well as aluminum.)
Of course, if you only had a big slab of solid silver. What about that sterling silver tea tray that you inherited from Grandma? It’s 92.5 percent silver, and it will work twice as well as that overpriced chunk of aluminum.