Sometimes when we're baking with our Dutch ovens, we want to create
air space for circulation so that our food doesn't burn on the bottom
before becoming thoroughly baked. For thirty years, my husband and I
have just crinkled foil to create a baking rack of sorts or inverted a
pan. I always
hated using crumpled foil; it seemed like such a waste of foil, but I
didn't just
want to hang onto the foil either. It takes up space and looks messy.
The inverted pan only worked if we had a pan that fit and that wasn't
being used for any other purpose that meal.
Last month, my good friend Lorna shared a tip with me. (I suppose, if she were a truly
good friend, she would have shared this tip thirty years ago.) Anyway,
it's genius, simple, compact, and cheap. It costs exactly fifteen
cents. To
create a baking rack in her Dutch oven, Lorna uses fifteen pennies,
three stacks of five pennies each. She puts them in an equilateral
triangle
configuration inside the Dutch oven, and sets the baking pan on top.
When not in use, she keeps her pennies in a small container used for
diabetic test strips; a prescription pill bottle would be just as good.
However, a caution came with it: Only pre-1962 pennies were safe to
use. Something just didn't seem right about that to me. Lorna's
husband is a banker and coin collector and explained that before 1962,
pennies were 95
percent copper, with the remaining 5 percent made up of tin and zinc.
In 1962, the formula was changed to 95 percent copper and 5
percent zinc. The issue apparently, was the amount of zinc being heated
in the oven. However, it seemed to me that a little alteration in the
metal composition of the pennies shouldn't make that much difference.
So I asked my soon-to-be metallurgical engineer son what he could tell
me. When zinc is heated, enough to melt it, zinc oxide is formed. Zinc
oxide is used to fortify breakfast cereals. It is added to
anti-dandruff shampoo, sunscreen, and diaper rash creams. The US FDA
lists zinc oxide as GRAS (generally regarded as safe).
So what's the issue? Well, breathing zinc oxide vapors is
hazardous. It causes metal fume fever. But you can only generate zinc
oxide vapors if you are welding or melting zinc or zinc alloys. Even
if you use more recently minted pennies, which are 97.5 percent zinc,
they are all coated with copper. No zinc is exposed. You are going to
have to be generating some pretty serious heat to melt zinc. If you've
got that kind of heat (zinc melts at 787 degrees Fahrenheit) cooking
your dinner, well, you're probably going to bed hungry, to say the
least, and no one is ever going to let you cook anything again.
20 december 2018