Sweet butter. Extra-virgin olive oil. Beta carotene. Ghee. They perfume the pesto and perfect the pie. They tint the fritter, puff the tempura, wring out our wrinkles and dissolve our scars. In the world of cooking, there's no ingredient more flexible than fat.
Ingredients come and ingredients go, but fat remains at the core of cuisine. As Waverly Root demonstrated when he divided the regional cooking of France between the provinces that rely on olive oil and those that rely on butter, our choice of fat has more to do with our expectations of flavor and texture in the foods we eat than any other single factor.
But as we argue about the risks and merits of fat or carbohydrates in our diets we find ourselves on shifting ground, trying to straddle the gap between what fat does for us and what it does to us.
In cooking, fat is the great equalizer. It collects heat gradually and maintains a constant temperature easily. Because it is fluid when hot, it can wrap around an ingredient completely, transferring its heat evenly and steadily into the tiniest crevice.
Unlike other liquids made from water, which vaporize at 212 degrees Fahrenheit, fats maintain their liquid states well past 400 degrees, giving them the ability to brown and crisp the surface of food - something steam and boiling water could never do.
A thin film of fat is enough to keep the gooiest batter from sticking to the griddle, and when smoking hot, it can cook through a chicken tender in a matter of seconds.
Chill a fat, and it shows its other talents. Cold fats are solid and malleable. Beaten with sugar, they capture air in millions of tiny pockets, and they hold on to it safely until the heat of the oven can use it to send a cake aloft. Fat is the tenderizer in a pie crust and the softener for breads. It makes cookies crisp, and puff pastry puffed. It is the cakey flake in a biscuit and the downy crumb of a just-warmed muffin.
Fat is our sense of juiciness represented in a grilled steak or a roasted bird. It is what carries the flavors of herbs and spices in salad dressings, marinades and sauces. Fat lubricates the flesh of a flaking fish and guarantees that the pasta never sticks. Fat keeps the cheese from crumbling. It smoothes the grit in ground beef and turns goose liver to foie gras.
If you delete fat completely from your diet, you'd subject yourself to disease and multiple handicaps, from lack of fat-soluble vitamins (beta carotene and vitamins A, D, and E) to brain damage. Fats are an integral component of cell membranes; they are required for the production of hormones, and they're essential for brain activity, and for the workings of the nervous system and liver.
Without fat, our bodies would break down. A problem in our culture is that many of us take in too much fat. Our bodies need relatively little of it to function, but we consume far more, about 40 percent of our calorie intake.
The main metabolic function of fat is energy storage. We get dietary energy in two forms: carbohydrates and fat. Carbohydrates come from plant sources and occur in food either as sugar or starch. Both provide quick energy, the amount of which is expressed in calories. If we take in more calories than we are able to utilize, the extra energy is stored as body fat.
We also get calories by consuming fats. These can come from either a plant or animal source, and are not immediately used for energy unless there is insufficient carbohydrate in the diet to meet an individual's energy needs. If we continue to take in more calories than we need - whether from fat or carbohydrate - we put on weight.
Add this to the well-known circulatory problems and incidence of colon cancer associated with high-fat diets, and you have the foundation of the fat-free doctrine, which at its extreme takes over our common-sense notion of what constitutes good food.
Fat is essential for the transference of flavor and the development of pleasant textures in food. It is a useful cooking ingredient and a necessary dietary component. Fat is not the enemy; too much fat is.
The cooking methods that rely on fat for heat transference are all performed similarly and to similar effect. The only difference is the amount of fat used and the temperature at which cooking takes place. The techniques include sautéing, pan-frying and deep-frying.
Sautéing is done in a shallow, wide-bottomed pan over the highest possible heat. Thin (no more than one-quarter-inch thick), tender slices of meat, poultry or fish are placed in a pan that has been greased with a film of oil, clarified butter or animal fat, and are heated until the fat begins to smoke (an indication that the temperature in the pan is around 500 degrees).
The pan must be hot enough - and the ingredients tender and thin enough - to cook through in the time they take to brown. Depending on variations in these factors, sautéing can take anywhere from 30 seconds to three minutes. If the ingredient requires longer than that, sautéing is not recommended.
Thicker or slower-cooking ingredients are better pan-fried than sautéed. Pan-frying starts out like sautéing except that there's a bit more fat in the pan, anywhere from an eighth of an inch to three-quarters of an inch, depending on the ingredient.
When using the lesser amount of fat, ingredients are browned on each side, then the heat is lowered to a moderate level and the food continues to heat gently until it is cooked through. This is the preferred method for frying latkes or boneless chicken breasts.
In deep-frying, bite-sized pieces of food are cooked in several inches of 375 degree-fat until brown and crisp. In this technique, the fat is kept at a constant temperature to ensure that the surface of the frying food is sealed on contact so that a bare minimum of fat is absorbed in the process. Because the temperature cannot be adjusted, the size of the frying pieces must be carefully considered, lest they burn before they are cooked through or dehydrate before they get a chance to brown.
Deep-fried foods can be breaded (chicken nuggets, fish sticks, croquettes), batter-dipped (tempura, fried cheeses) or uncoated (French fries). Coatings absorb surface moisture and cut down on splattering. They also help to keep fat away from the food so effectively that if you remove the breading from a properly fried ingredient, it will have a fat content no greater than if it had been steamed.
Although frying will never be a low-fat cooking method, it is not necessarily as harmful as we think. Provided that the fat is hot enough (375 degrees or higher), the surface of the food sets as soon as it is immersed in the fat. At that point, the interchange of fluid is much more a matter of steam traveling out of the food than oil traveling in.
Though we talk of fat as a single entity, there are many different types. For culinary purposes, we categorize fats according to their viscosity at a given temperature. Oils are fats that are liquid at room temperature.
Fats are fats that are solid at room temperature. Generally, oils come from plant sources while fats come from animals, with the exception of cocoa butter, which is solid at room temperature.
The more solid a fat is, the more saturated it is. We typically speak of one fat as being saturated and another as unsaturated, but saturation is actually a continuum without clear division lines. Liquid canola oil is less saturated than more viscous olive oil, which is less saturated than chicken fat.
Without getting into health comparisons, the saturation level of a fat has much to do with how it should be used in cooking. Dense fats like shortening, butter, and margarine are best for baking. Their thickness is essential to properly aerate cakes and to give a pastry its flake.
Oil produces dense cakes, such as carrot cake, which are rich and moist but without the delicate crumb that is the sign of a cake made from butter or shortening.
When making pie crust, biscuits or shortcakes, the solidity of the fat determines the length of the flake. The more completely a fat is mixed with flour in a dough, the less flaky the dough will be.
Obviously, liquid fats, like oils, combine with the flour entirely, yielding a product with such a small flake that its texture is best described as sandy.
Less saturated fats are preferred for frying, because they do not burn and smoke as easily as more solid fats. All fats will burn if heated high enough, but the smoking point for each is different, depending on its chemical composition.
Saturation is the main factor influencing the smoking point. The less saturated a fat is, the higher it can be heated before it starts burning and smoking. For instance, chicken fat begins to burn around 375 degrees, peanut oil at 440 degrees, and safflower oil at 510 degrees. So chicken fat may be just right for adding flavor, but it is a poor choice for sautéing.
Once a fat begins to burn, it breaks down, and its chemical structure changes. It will begin to let off noxious fumes, and when it cools it will no longer have the same properties it had before. So a fat should not be reused once it has been heated enough to smoke.
Fats are best stored in as cool and dark a place as possible, in tightly sealed containers that fit their contents closely. The main danger in fat storage is rancidity. Fats go rancid when they are exposed to air and light; the less saturated they are, the more prone they are to developing rancid compounds. That's why all fats, especially oils, should be kept refrigerated.
Many oils will turn cloudy in the refrigerator. All that signifies is that they are becoming cold enough to start to solidify. The change is not harmful, and the oil will return to its liquid state as soon as it is heated.
Now that you know more than you ever wanted to about fats and frying, here's a raucous Chanukah latke recipe that will be a welcome change from plain potato. For the rest of the year comes another indulgence –– homemade potato chips.
Harvest Vegetable Pancakes
1 lb. peeled carrots, shredded
1/2 lb. peeled beets, finely shredded
1/2 lb. peeled parsnip, shredded
1/2 lb. peeled baking potato, shredded
3 eggs, beaten
1 tsp. lemon juice
2 Tbsps. flour
1 tsp. salt
pepper to taste
3 Tbsps. finely chopped onion
olive oil for frying
2-3 cups applesauce
Combine the carrots, beets, parsnip, potato, eggs, lemon juice, flour, salt, pepper and onion.
Heat one-quarter to one-half of an inch of oil in the bottom of a large skillet over medium-high heat until the surface shivers.
Place heaping soup spoonfuls of the batter in the hot oil (it should splatter immediately), flattening the mounds so that they form pancakes about 3 inches in diameter.
Brown well, about 5 minutes per side. Drain on paper towels.
Serve hot with applesauce.
Makes 4 to 6 servings.
Spiced Potato Chips
2 lbs. russet potatoes, scrubbed and sliced paper-thin
4 cups ice water
1 Tbsp. salt
1/8 tsp. cayenne pepper
1/2 tsp. ground cumin seed
vegetable oil, for frying
Soak the potatoes in the water, mixed with 2 teaspoons of the salt, for 10 minutes.
Mix the remaining salt with the cayenne and cumin. Set aside.
Meanwhile, fill a heavy saucepan with 2 to 3 inches of oil.
Heat to 350 degrees (at this temperature, a cube of bread dropped into the oil will sizzle within 10 seconds of contact). Add the potatoes in batches, and fry until lightly browned. Remove, and drain on paper towels.
Just before serving, heat the oil to 375 degrees. Add the potatoes in batches and fry until crisp.
Drain on paper towels, and then season with the salt mixture.
Makes 4 to 6 servings.
Andrew Schloss is a food-industry consultant and a cookbook author. His current book is Almost From Scratch: 600 Recipes for the New Convenience Cuisine.