Health directories: What Cooking Really Is ?

Cooking, at its most basic, is simply the transfer of energy from a heat source to a food product. The transfer of energy alters the molecular structure of food, changing its color, texture, flavor, and aroma. Cooking not only makes food taste better but it kills harmful bacteria that can be destructive to our bodies and it makes food easier on our digestive system.

The transfer of energy during cooking occurs with heat. This transfer can happen in one of three general ways: conduction, convection, or radiation.

CONDUCTION

In culinary terms, conduction is the movement of heat from one item to another through direct contact. An example is sautéing: energy is transferred from the flame to the pan to the food. In the culinary world, conduction also happens inside your food as it’s cooked, no matter what cooking technique you use. That’s because your food is a whole bunch of bound molecules. When the molecules on the outside heat, they transfer the heat further inside through direct contact with other molecules, or by means of conduction.

CONVECTION

Convection is the transfer of heat through a fluid, either liquid or gas. There are two types of convection: natural and mechanical.

Natural convection refers to the movement created by heating a liquid or a gas. Remember in 6th grade science when we learned how heat rises? Well, that happens in liquids, too. When you put a pot of water on the stove and turn the heat on, the water molecules at the bottom heat first and as they heat, they get lighter and rise to the top of the pot. The cooler molecules then fall and as they fall, they get closer to the heat source where they heat. This creates a constant flow of water molecules from the top (where it’s cooler) to the bottom (where they heat), back to the top (where they cool slightly), then again to the bottom to heat,… and so on. The heat from the water is then transferred to the food.

Mechanical convection happens the same way, only in ovens, and the medium is a gas instead of a liquid. Expensive convection ovens have fans in them that circulate the air evenly for quicker, more even cooking. Even standard ovens use convection but rely on natural heat patterns to circulate hot air.

RADIATION

Radiation is the process of transferring energy to food by waves of heat or light. It’s the only method where food doesn’t come in direct contact with a heat source or conductor. There are two types of radiation: infrared and microwave.

Infrared cooking uses an electric or ceramic heat source that gets crazy hot to transfer radiant heat through food. During infrared cooking, the radiant heat waves travel in every direction until they’re absorbed by food, as opposed to convection cooking where heat waves only rise. Two common examples are toasters and broilers.

Microwave cooking only affects the water molecules in food but it transfers energy to those molecules more evenly than any other cooking method. Because only water molecules are affected, items without water molecules will not heat in a microwave. Like a bowl, for example. The only way a ceramic bowl can get hot in a microwave is if it holds food that is heated.

Every type of food prefers a particular cooking method but no food prefers a microwave. Among other things, it makes bread soggy and meat mushy so it’s not a suitable replacement for a standard oven.

COOKING METHODS

There are two main categories of cooking methods: dry-heat or moist-heat. In addition, there are combination cooking methods that employ both dry-heat and moist-heat at different stages in cooking.

DRY HEAT METHODS

SAUTÉING / SEARING

• Medium: Fat

• Equipment: Stove, pan

PAN-FRYING

• Medium: Fat

• Equipment: Stove, pan

DEEP-FRYING

• Medium: Fat

• Equipment: Stove & pan or deep fryer

GRILLING

• Medium: Air

• Equipment: Grill

ROASTING

• Medium: Air

• Equipment: Oven

BAKING

• Medium: Air

• Equipment: Oven

BROILING

• Medium: Air

• Equipment: Broiler (oven) or Salamander (in commercial kitchens)

MOIST HEAT METHODS

STEAMING

• Medium: Steam

• Equipment: Stove or steamer

POACHING

• Medium: Water-Based Liquid