Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingested by an organism and assimilated by the organism's cells in an effort to produce energy, maintain life, or stimulate growth.
Historically, people secured food through two methods: hunting and gathering, and agriculture. Today, most of the food energy consumed by the world population is supplied by the food industry.
Cooking or cookery is the art or practice of preparing food for consumption with the use of heat. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training. Cooking can also occur through chemical reactions without the presence of heat, most notably as in Ceviche, a traditional South American dish where fish is cooked with the acids in lemon or lime juice. Sushi also uses a similar chemical reaction between fish and the acidic content of rice glazed with vinegar.
Preparing food with heat or fire is an activity unique to humans, and some scientists believe the advent of cooking played an important role in human evolution. Most anthropologists believe that cooking fires first developed around 250,000 years ago. The development of agriculture, commerce and transportation between civilizations in different regions offered cooks many new ingredients. New inventions and technologies, such as pottery for holding and boiling water, expanded cooking techniques. Some modern cooks apply advanced scientific techniques to food preparation.
The cuisine of the Americas is made up of a variety of food preparation styles.
A baked potato, or jacket potato, is the edible result of baking a potato. When well cooked, a baked potato has a fluffy interior and a crisp skin. It may be served with fillings and condiments such as butter, cheese or ham. Potatoes can be baked in a conventional gas or electric oven, a convection oven, a microwave oven, on a barbecue grill, or on/in an open fire. Some restaurants use special ovens designed specifically to cook large numbers of potatoes, then keep them warm and ready for service.
Prior to cooking, the potato should be scrubbed clean, washed and dried with eyes and surface blemishes removed, and possibly basted with oil or butter and/or salt. Pricking the potato with a fork or knife allows steam to escape during the cooking process. Potatoes cooked in a microwave oven without pricking the skin might split open due to built up internal pressure from unvented steam. It takes between one and two hours to bake a large potato in a conventional oven at 200 °C (392 °F). Microwaving takes from six to twelve minutes depending on oven power and potato size, but does not generally produce a crisp skin.
A Russian oven or Russian stove (Russian: Русская печь) is a unique type of oven/furnace that first appeared in the 15th century. It is used both for cooking and domestic heating. The Russian oven burns firewood or wood manufacturing waste.
Various types of firewood can be used, for example birch or pine. Aspen is the least efficient for heating a Russian oven because the amount needed is twice that of other woods.