MOST people who cook would agree that pots and pans are the heart and soul of the kitchen. And that's where the agreement about pots and pans usually ends. There are partisans for all sides--copper, aluminum, stainless, coated aluminum, cast iron, enameled cast iron or combinations. Sets or a mishmash. Straight-sided frying pans, slope-sided frying pans. Silverstone, T-Fal, Calphalon.

This column and the next will attempt to hack a path through the overgrown forest of information that surrounds the simple, homely cooking pot. First, a discussion of the basic materials and how they behave.

The truth is that most cooks develop culinary objects of affection that only they understand--a battered batterie de cuisine that works for them despite its origins. And people who cook a lot have generally given up on the ideal of a perfect, matched, gleaming set of anything. No one material will do everything well, and no matter what the material is, if it's used a lot it will show the battle scars.

The pot rack of one experienced Washington cook, Ann Yonkers, who developed and administers an elementary school cooking program and who is now beginning to teach cooking in her home, is a case in point. One of Yonkers' favorite implements is an ancient 12-inch aluminum Wearever skillet, a piece of equipment that has been around long enough that she and it understand each other perfectly. It hangs next to a Calphalon (treated aluminum) saucepan and chicken fryer, two tin-lined copper saucepans, a well-used Copco aluminum omelet pan (which Yonkers also uses for crepes), a black, cast-iron skillet, a couple of stainless steel pots, and a carbon-steel wok. On a high shelf, in well-lit splendor, is a beautiful hammered copper soup pot big enough to feed legions and lovely enough to put on the dining room table.

Why the eclectic collection? Partly because these pieces were collected gradually over time, and partly because each material and each shape behaves differently.

Copper is the most expensive and revered of the cookware metals, and the one that conducts heat the best. Good heat conduction means that the metal spreads heat from the burner quickly across the bottom and up through the sides of the pan. It means that if you are saute'eing onions in a pan bigger than your burner you will not end up with a circle of burned onions in the middle of the pan surrounded by a ring of uncooked onions. A metal that conducts heat well heats up quickly and cools off quickly, so that if you are making custard or hollandaise and need to stop the cooking action quickly the pot will respond.

Copper cookware can be used for any kind of cooking, but it is not ideal for things like omelets that require extremely high heat because the tin lining softens at very high temperatures (especially if the pot is empty). But you can certainly saute' in copper.

Copper is not usually used in direct contact with food because it reacts chemically with some food elements, causing discoloration and a metallic taste. And unlined copper used with acid foods can cause illness. As a result, copper cooking pots have traditionally been lined with a thin wash of tin, a soft metal that protects the food and the copper from each other, but doesn't interfere dramatically with heat conduction. Unlined copper is used, however, for whipping egg whites, melting sugar and making zabaglione.

Despite its expense, many experienced cooks eventually gravitate toward copper not only for the way it cooks but also for the way it feels in the hand. There is something intensely satisfying about the heft and look of a hotel-weight copper pot.

Just because a pot is copper doesn't mean it is good to cook in. There is a lot of flimsy copper on the market. One store in the Washington area with good prices and a consistently good supply of both presentation-weight and the heavier hotel-weight copper cookware, is La Cuisine on Cameron Street in Alexandria.

Aluminum is a lot cheaper than copper and conducts heat almost as well. An aluminum pot will be much lighter in weight than a copper pot of similar gauge. Aluminum also reacts to certain foods, however, and will discolor delicate sauces that contain acids like wine or vinegar and cause an off-taste in egg-based sauces. Acid foods will also tend to pit and discolor the aluminum.

There is probably more variation in the quality and gauge (thickness) of aluminum cookware than in any other metal, and gauge makes a tremendous difference in how well the metal takes and transfers heat. Thin, cheap aluminum is useless for anything but heating up a can of soup, but heavy-gauge, well-made aluminum cookware has been the standard in restaurants and other professional kitchens for decades.

A 10-inch frying pan in the heaviest gauge tin-lined copper available will cost around $100. A similar pan in heaviest gauge, untreated aluminum will cost around $30.

Cast iron has been used for centuries. It holds heat better than any other metal, making it perfect for slow-cooking things like soups and stews, but it is not responsive to quick changes in heat and therefore not ideal for quick saute'es or heat-sensitive sauces. Uncoated cast iron rusts easily when it comes in contact with liquids, and will discolor foods if not well seasoned before using. But despite its problems, the old cast-iron skillet is the one piece of equipment many cooks would carry out with them if the house caught on fire. Because it takes and holds steady heat, a well-seasoned cast-iron skillet is unparalleled for frying things like bacon, potatoes or grilled cheese sandwiches.

An enamel coating on cast iron alleviates, but does not completely solve the rust problem. Even enamelled cast iron will rust around the edges if it stays wet. The enamel coating can also chip, though this is usually a only a matter of esthetics.

Stainless steel is the metal of choice for cooks who prize cleanliness over good heat conduction. It doesn't stain, crack, chip or rust, but neither does it move heat around very well. It is prone to warping and developing hot spots. Because it is very hard it cleans easily without staining, making it suitable for messy projects like heating milk. It also does not transfer any metal to sauces or discolor them. When it is combined with other metals like aluminum or copper, its heat-resistant qualities are ameliorated but not eliminated completely.

NEXT: Combinations of materials, variations of shape and size, seasoning and care.