Tue December 24, 2013
Hair Dryer Cooking: From S'mores To Crispy Duck
Originally published on Thu December 26, 2013 7:54 am
This past year, we've introduced you to some wacky cooking methods. We've made an entire lunch in a coffee maker and even poached salmon and pears in the dishwasher.
But a few weeks ago, we stumbled upon a crazy culinary appliance that may be the most legitimate of them all: the hair dryer.
Now, before you think we've fallen off the kitchen stool from too much eggnog, check out the science and history behind the idea.
The technique dates back to 1978, and it was pioneered by culinary guru Marcella Hazan, whom you might call the patron saint of Italian cooking in America.
Hazan's classic recipe for roast duck contains this unusual twist: Dunk the duck in boiling water and then thoroughly go over it with a hair dryer, Hazan writes in Essentials of Classic Italian.
The result, she says, is duck skin that's "succulent" and "deliciously crisp" but not oily.
We'll explore exactly how the blow dryer helps crisp up poultry skin in a moment. But first, a bit of background — and some fun with chocolate.
The food scientists over at America's Test Kitchen offer up three reasons to keep a hair dryer in the pantry:
1- relighting charcoals on the grill
2- putting a glossy sheen on cake frosting and
3- softening up a bar of chocolate to make it easier to shave off slivers.
Many of us don't have the time to give our cake frosting a professional blowout, but softening up chocolate struck a chord and made us immediately think of one thing: blow dryer s'mores!
Most hair dryers produce air that's about 200 degrees Fahrenheit when the nozzle is about 2 inches from a surface. That's the perfect temperature for melting chocolate (or butter) without burning it.
So we tried making hair dryer s'mores here at NPR headquarters with some dark, 70 percent chocolate. And, well, we were blown away.
Seconds after the hot air hits the candy's surface, the dark chocolate starts to get glossy. Then it quickly turns into a chocolate fountain flowing across the graham cracker. (Note: You do have to hold the chocolate down with a fork or chopstick to keep it from blowing off the plate).
The dryer will also melt the marshmallow. But the air from the appliance is too cool to toast the marshmallow and give it a brown color. Caramelization of sugar and other browning reactions occur only at temperatures above 350 degrees Fahrenheit.
If your blow dryer got that hot, it would make your hair crispier than the skin of a Peking duck hanging in a Chinatown shop. Which brings us back to Hazan's use of the hair dryer in the kitchen: getting the perfect skin on your holiday duck or chicken.
"To crisp up and brown, the skin has to heat up to a high temperature — above 300 degrees Fahrenheit," says Guy Crosby, the science editor at America's Test Kitchen and a lecturer in food chemistry at Harvard University. "So the bird's flesh has to go into the oven very, very dry."
If there's any moisture in the skin, Crosby says, all of the heat will go into boiling off the water, and the skin won't get above 212 degrees Fahrenheit.
In the classic recipe for Peking duck, the bird gets dried out by hanging in the open air for 10 to 12 hours. Hazan replaces that long dehydration step with a quick blowout of the bird.
"Pat it [the duck] dry inside and out with paper towels," she writes in the Essentials of Classic Italian. "Turn on the hair dryer and direct the hot air over the whole skin of the duck for 6 to 8 minutes."
The same idea can be applied to chicken, turkey and even fish, Crosby says. "Anything that you want to sear or crisp, get it in the pan as dry as possible — get rid of the moisture."
For the duck, though, the blow dryer serves a second function: It removes some of the fat.
What gives poultry skin its yummy texture isn't the oily fat but rather the proteins. "Fat contributes a great deal of flavor to the skin," Crosby says. "But the crispy structure comes from heating up the protein."
When the duck is raw, proteins in the skin form long chains, like a curtain of ropes or beads. These flexible strands make the skin soft and flexible. But as the duck heats up, sugars in the skin start to link the protein chains together. This makes the skin firm and crispy.
"Think about the frame of a house," Crosby says. "If all you had were vertical studs, the frame is not stable. But if you put some horizontal studs in it, they make the frame rigid. That's what the sugars are doing" during the browning process.
Duck skin has so much fat in it that it can get in the way of connecting up the proteins and, thus, the crisping process. Some of the fat streams out of the skin during the blow drying.
But this step also opens up the skin's pores, so that even more fat can drip out during the roasting process. And less fat means crispier skin.
Have a holly jolly hair dryer holiday!