UNFREEZING YOUR ASSETS
What’s the best and fastest way to defrost frozen foods?
I
know what you mean. You come home after a hard day’s work. You don’t feel like cooking, and you can’t face the hassle of going to a restaurant. Where do you turn?To the freezer, of course. And like a crowd of football fans, a little voice in your head begins to chant, “DEE-frost! DEE-frost!”
Scanning your frozen assets, you’re wondering not so much about what is in there (“Why didn’t I label those packages?”), but about what would defrost in a minimum amount of time.
Your options are (a) leaving it out on the kitchen counter while you go through the mail, (b) soaking it in a sink full of water or (c) the best and fastest method of all, which I shall divulge in due time and which, I promise, will astound you.
For commercially packaged frozen foods, just follow the directions. You wouldn’t believe the armies of home economists and technicians who slaved away to determine the best methods of defrosting their company’s products in the home kitchen. Trust them.
While the defrosting directions on commercial packages often involve a microwave oven, that usually doesn’t work for thawing home-frozen foods, because it’s hard to keep the outer regions of the food from beginning to cook.
“Frozen food” is something of a misnomer. Technically speaking, freezing means converting a substance from its liquid form into its solid form by cooling it below its freezing point. But meats and vegetables are already solid when they are put into the freezer. It’s their water content that freezes into tiny ice crystals, and those ice crystals are what make the whole food hard. The job of defrosting, then, is to melt those tiny ice crystals back to their liquid form.
How do you melt ice? Why, you heat it, of course. Your first problem, then, is to find a source of low-temperature heat. If that phrase sounds paradoxical, please realize that heat and temperature are two very different things.
Heat is energy, the energy that moving molecules have. All molecules are moving to some extent, so heat is everywhere, in everything. Even an ice cube contains heat. Not as much as a hot potato, but some.
On the other hand, temperature, as I have pointed out earlier, is just a convenient number by which we humans express how fast the molecules are moving. If the molecules of one substance are moving faster, on the average, than those of another, we say that the first substance has a higher temperature, or is hotter, than the other.
Heat energy will travel automatically from a warmer substance into an adjecent, cooler one, because the faster molecules in the warmer one can bang against the molecules of the cooler one, making them move faster. Obviously, then, we could warm our frozen food most quickly by putting it in contact with a hot substance, such as the air in a hot oven. But that would cook the outer parts of the food before much heat could penetrate into the inner parts.
The air in your kitchen is at a very moderate temperature compared with the air in a hot oven, but it still contains a lot of heat that can be tapped to defrost frozen food. So should we just leave
the food out in the air? No. It would take too long for the air to transfer its heat, because air is just about the worst conductor of heat that you can imagine. Its molecules are just too far apart to do much banging against other molecules. Besides, slow air-thawing is dangerous because bacteria can grow rapidly on the outside portions that are first to thaw.
How about soaking in water? Water is a much better heat conductor than air is, because its molecules are much closer together. If the food package is waterproof (and if you’re not sure, seal it in a zipper-top bag after pressing out most of the air), then by all means soak it in a bowl—or in the case of a whole chicken or turkey, a sink or bathtub—full of cold water. Since the frozen bird will make the water even colder, change the water every half hour or so and the whole process will go even faster.
The quickest method of all, I now reveal, is to place the unwrapped frozen food on an unheated, heavy skillet or frying pan. Yes, unheated. Metals are the champion heat conductors of all substances, because they have zillions of loose electrons that can transmit energy even better than clashing molecules can. The metal pan will conduct the room’s heat very efficiently into the frozen food, thawing it in record time. The heavier the pan the better, because thicker metal can conduct more heat per minute. Flat foods like steaks and chops will thaw fastest, because they make the best contact with the pan, so keep this in mind when making up your packages for the freezer. (Round, bulky roasts and whole chickens or turkeys won’t thaw much faster on the pan than on the counter; however, neither method is recommended because of the danger of bacterial growth. Thaw them either in cold water or in the refrigerator.) Nonstick pans won’t work, incidentally, because the coatings are poor heat conductors, nor will a cast-iron pan because it is porous.
I discovered the frying-pan gimmick while experimenting with one of those “miracle”
defrosting trays sold in catalogs and cookware stores. They are reputedly made of an “advanced, space-age super-conductive alloy” that “takes heat right out of the air.” Well, the space-age alloy turns out to be ordinary aluminum (I analyzed it), and it “takes heat out of the air” exactly the way an aluminum frying pan does, and for exactly the same reasons.
So save the water method for the bulky stuff and just put that frozen steak or fillet on a heavy frying pan. It’ll be thawed before you can say, “Where did I put those frozen peas?” Well, not quite, but a lot sooner than you’d think.
HOW TO MAKE A COOL BUNCH OF DOUGH
Why do cookbooks recommend rolling out pastry dough on a marble surface?
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astry dough must be kept cool during rolling so that the shortening—most often a solid fat such as butter, lard, or Crisco—doesn’t melt and soak into the flour. If it does, your piecrust will have the texture of a shipping carton. Flaky pastry is produced when many thin layers of dough are kept separated from one another by layers of fat. In the oven the separated dough layers begin to set, and by the time the fat melts, steam from the dough will have forced the layers permanently apart.Marble is recommended for the rolling surface because, according to the books, it is “cool.”
But that’s playing fast and loose with the concept of temperature, because the marble isn’t one bit cooler than anything else in the room.
But, you protest, the marble feels cold. Yes, it does. And so does the “cold steel” of your chef’s knife and every one of your pots, pans, and dishes. In fact, run into your kitchen right now (I’ll wait), pick up anything at all except the cat and hold it against your forehead. By George, everything feels cold! What’s going on here?
What’s going on is that the temperature of your skin is about 95ºF, while the temperature of your kitchen and everything in it is around 70ºF. Is it any surprise, then, that things should feel cold if they actually are 25 degrees colder than your skin? When you touch such an object, heat flows from your skin into the object, because heat always flows from a higher temperature to a lower one. Your heat-deprived skin then sends the message “I feel unusually cool” to your brain.
So it’s not that the object is cold; it’s that your skin is hot. As Einstein never said, “Everything is relative.”
But all things won’t feel equally cold, even though they are all at the same 70ºF room
temperature. Go back to the kitchen, please. Notice that the steel blade of your chef’s knife feels colder than, say, the wooden cutting board. Is it actually colder? No, because the two objects have been in the same environment long enough to have come to the same temperature.
The steel knife blade feels colder on your forehead than the wooden cutting board does because steel, like all metals, is a much better conductor of heat than wood is. When in contact with your skin, it conducts heat away into the room much faster than the wood can, thereby cooling your skin faster.
Marble isn’t as good a heat conductor as metal, but it’s ten to twenty times better than a wood or plastic-laminate countertop. Just as marble feels cold to your skin because it steals away heat, the marble feels cold also to the pastry dough because it removes the rolling-generated heat rapidly. Thus, the dough doesn’t warm up enough to melt the shortening.
Okay, okay, so I’m splitting hairs. If something feels cold, acts cold, and does everything but quack like a cold duck, why the heck can’t we just say that it’s cold? So be my guest. Say that marble is cold. But take secret pleasure in the knowledge that it isn’t strictly correct.
Cold-Rolled Pastry Easy Empanadas
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n Spanish, empanada means “breaded,” derived from pan, meaning bread. But that’s a bit misleading, because in Latin America today an empanada is a filled pastry—almost any kind of pastry made from flour or cornmeal and filled with almost anything imaginable, but usually with meats or seafoods of some kind. We might call them turnovers or individual meat pies, and they can be either baked or deep-fried. Every Latin American country has its own versions. They go together quickly if you organize your work area like an assembly line.In this variation, a traditional filling is wrapped in store-bought puff pastry instead of homemade pastry crust. This avoids the effort of making dough. But with puff pastry it’s particularly important to do the rolling on a “cool” surface such as marble. If marble is not available, roll it out as quickly as possible on a wooden board.
You will find frozen puff pastry sheets in the freezer section of your supermarket. Ground turkey or chicken can be substituted for the beef.
One 17-ounce package frozen puff-pastry sheets 1 tablespoon olive oil
½ cup finely chopped onion
½ cup finely chopped red bell pepper 1 clove garlic, finely minced
1 pound lean ground beef 2 teaspoons all-purpose flour 1 tablespoon chili powder 1 teaspoon salt
½ teaspoon hot pepper flakes
½ teaspoon dried oregano
½ teaspoon ground cumin
¼ teaspoon ground cloves Freshly ground pepper to taste 3 tablespoons ketchup
1 large egg yolk mixed with 1 tablespoon water
1. Thaw the puff pastry for 8–12 hours in the refrigerator.
2. Heat the oil in a large skillet over medium-high heat and cook the onion and pepper until soft, 5 minutes. Add the garlic and cook 1 minute longer. Add the ground meat and cook until it is browned and crumbles, about 5 minutes. Pour off the accumulated fat.
Remove from the heat.
3. In a small bowl, stir together the flour, spices, and seasonings. Add to the meat mixture and mix well. Add the ketchup and mix again. Check the seasonings. It should be spicy.
4. Transfer the mixture to a 10-by 15-inch cookie tray, and spread it out in a thin layer to cool. The empanadas are quickly made if you take an assembly line approach. Divide the filling into 18 small portions of 2 tablespoons each. Here is one way: Using a metal spatula, push the filling into 3 long rows, then divide each row into 6 sections so that the filling is now in 18 small portions. Set aside until needed.
5. Preheat the oven to 400ºF.
6. Remove one thawed puff pastry sheet from the refrigerator. Place it on a well-floured work surface. The sheet will be rather stiff. As soon as it is just warm enough to be unfolded without cracking, open it out flat. Dust both sides with a little flour.
7. With a sharp knife, cut the pastry sheet into three long strips along the fold lines. Cut each strip into three 3-inch squares. Using a rolling pin, roll each square into a by 5-inch square. Flour the squares lightly and stack them to one side. Repeat with the second sheet of pastry. You will have 18 squares.
8. Make the empanadas: Place one square of pastry on the floured surface. Using a small, soft brush, paint a ½-inch strip of egg wash on the left and bottom edges of the square. Place one portion of the meat mixture onto the square slightly toward the brushed corner. Fold over the other half of the pastry to make a triangular turnover.
Press the cut edges together. With the tines of a fork, pinch the edges together to seal.
With a sharp knife, cut off the ragged edges, if necessary. Transfer the turnover to a baking sheet. Repeat until all of the pastry and filling are used.
9. Lightly brush the empanadas with the remaining egg wash. With the tip of a small knife, poke two holes in the top of each so that steam can escape. Bake for 18 to 20 minutes until puffed and browned. Wrap individually and freeze.
MAKES 18 EMPANADAS
HOT WATER FREEZES FASTER!
My guests were due to arrive for a party in three hours and I needed to make some ice in a hurry.
I’ve heard that hot water freezes faster than cold water. Should I have put hot water in my ice-cube trays?
T
he hot-water-freezes-faster paradox has been debated since at least the 17th century when Sir Francis Bacon wrote about it. Even today, Canadians claim that a bucket of hot water left outdoors in cold weather will freeze faster than a bucket of cold water. Scientists, however, have been unable to explain why Canadians leave buckets of water outdoors in cold weather.But believe it or not, hot water really may freeze faster than cold water. Sometimes. Under certain conditions. It depends on a lot of things.
Intuitively, it seems impossible because the hot water simply has further to go in its downhill race toward 32°F. In order to chill down by each four degrees, a pint of water has to lose about one calorie of heat. So the more degrees the water has to fall, the more heat must be taken out of it, and that means a longer cooling time, all other things being equal.
But according to Wolke’s Law of Pervasive Perversity, all other things are never equal. As we’ll see, hot and cold water are different in more ways than their temperatures.
When cornered and pressed for an explanation of how hot water could possibly freeze first, chemists are likely to mumble something about cold water containing more dissolved air, and dissolved substances lower the freezing temperature of water. True, but trivial. The amount of dissolved air in cold tap water would lower its freezing temperature by less than a thousandth of a degree Fahrenheit, and no hot-cold race can be controlled that precisely. The dissolved-air explanation just doesn’t hold water.
A real difference between hot and cold water is that the hotter a substance is, the faster it
radiates its heat away into the surroundings. That is, warmer water cools off at a faster rate—more degrees per minute—than cooler water does. The difference is especially great if the containers are shallow, exposing large surfaces of water. But that still doesn’t mean that the hot water will reach the finish line first, because no matter how fast it cools off at first, the most it can do is catch up with the cold water. After that, they’re neck and neck.
A more significant difference between hot and cold water is that hot water evaporates faster than cold water. So if we start by trying to freeze equal amounts of hot and cold water, there will be less water remaining in the hot-water container when it gets down to rug-cuttin’ time at 32ºF.
Less water, naturally, will freeze in less time.
Can that really make a significant difference? Well, water is a very unusual liquid in many ways. One of those ways is that an unusually large amount of heat must be removed from water before its temperature will go down very much. (Techspeak: Water has a high heat capacity.) So even if the hot container has lost only slightly more water by evaporation than the cold container has, it may require a lot less cooling time to freeze.
Now don’t go running into the kitchen to try it with ice-cube trays, because there are simply too many other factors operating. According to Wolke’s Law, the two trays can never be identical.
They are not in exactly the same place at exactly the same temperature, and they are not necessarily being cooled at the same rate. (Is one closer to the cooling coils in the freezer?) Moreover, how are you going to tell exactly when the water freezes? At the first skin of ice on top?
That doesn’t mean that the whole tray full has yet reached 32ºF. And you can’t peek too often, because opening the freezer door can cause unpredictable air currents that will affect the evaporation rates.
Most frustrating of all, undisturbed water has the perverse habit of getting colder than 32ºF before it freezes. (Techspeak: It super-cools.) It may refuse to freeze until some largely unpredictable outside influence perturbs it, such as a vibration, a speck of dust, or a scratch on the inside surface of its container. In short, you’re running a race with a very fuzzy finish line.
Science isn’t easy.
But I know that won’t stop you. So go ahead and measure out equal amounts of hot and cold water, put them in identical (ha!) freezer trays, and don’t bet too much on the outcome.
HUMPTY DUMPTY NEVER HAD IT SO BAD
Can raw, whole eggs be frozen? I have almost two dozen eggs that I won’t be able to use up before I go on a trip and I’d hate to have them go to waste.