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Airdate: Sep 07, 2004
Scientist: Harold McGee

Bread: Preserving

Bread: Preserving
Contrary to popular belief, refrigeration is not the best way to preserve the freshness of bread.



What's the most effective way to prevent bread from going stale? The answer may surprise you. I'm Jim Metzner, and this is the Pulse of the Planet.

"Staling is a process whereby, the starch and the moisture inside the loaf of bread change their, organization, with respect to each other. The starch absorbs a lot of water during baking and then once the bread cools down, some of that moisture escapes from the starch and the starch gets hard again."

Harold McGee is the author of the book "Food and Science." He says the best way to preserve bread runs counter to our expectations.

"It turns out that the staling process, which involves a change in the structure of the starch in the bread dough, happens at a much faster rate at temperatures right around refrigerator temperatures. So in fact, if you want to keep bread edible for a few days, the best thing to do for it is just to keep it at room temperature. It'll actually stale much more slowly at room temperature than it will in the refrigerator, which we would normally think of as a place to make things last longer. If you want to keep bread for more than just a few days, the best thing to do is to freeze it, because the temperature of the bread passes through refrigerator temperature pretty quickly on its way to getting completely frozen. And so it spends relatively little time in that critical temperature range and doesn’t stale as badly."

And once bread goes stale . . .

"ll you have to do is essentially cook the bread again. And so that’s why we toast bread. Of course you brown the outside and that gives you a nice flavor, but what happens on the inside is that the, the starch is able to reabsorb some of the moisture it lost and it becomes a nice piece of bread again."

Pulse of the Planet is presented with support provided by the National Science Foundation. I'm Jim Metzner.