Thursday, January 8, 2009

Boiling in cookery

Boiling in cookery
Boiling water

In cookery, boiling is the method of cooking food in boiling water, or other water-based liquid such as stock or milk. Simmering is gentle boiling, while in poaching the cooking liquid moves but
scarcely bubbles.
Boiling is a very harsh technique of cooking. Delicate foods such as fish cannot be cooked in this fashion because the bubbles can damage the food. Foods such as red meat, chicken, and root vegetables can be cooked with this technique because of their tough texture.

The open-air boiling point of water is typically considered to be 100 °C or 212 °F.
Depending on the type of food and the elevation, the boiling water may not be hot enough to cook the food properly. Similarly, increasing the pressure as in a pressure cooker raises the
temperature of the contents above the open air boiling point.

Adding a water soluble substance, such as salt or sugar also increases the boiling point. This is called boiling-point elevation. However, the effect is very small, and the boiling point will be
increased by an insignificant amount. Due to variations in composition and pressure, the boiling point of water is almost never exactly 100 °C, but rather close enough for cooking.

In places where the available water supply is contaminated with disease-causing bacteria, boiling water and allowing it to cool before drinking it is a valuable health measure. Boiling water for a
few minutes kills most bacteria, amoeba, and other microbial pathogens. It thus can help prevent cholera, dysentery, and other diseases caused by microorganisms.

Foods suitable for boiling include vegetables, starchy foods such as rice, noodles and potatoes, eggs, meats, sauces, stocks and soups.Boiling has several advantages. It is safe and simple, and it is appropriate for large-scale cookery. Older, tougher, cheaper cuts of meat and poultry can be made digestible. Nutritious, well flavoured stock is produced. Also, maximum color and nutritive value is retained when cooking green vegetables, provided boiling time is kept to the minimum.

On the other hand, there are several disadvantages. There is a loss of soluble vitamins from foods to the water (if the water is discarded), and some boiled foods can look unattractive. Boiling can also be a slow method of cooking food.

Boiling can be done in two ways: The food can be placed into already rapidly boiling water and left to cook, the heat can be turned down and the food can be simmered; or the food can also be placed into the pot, and cold water may be added to the pot. This may then be boiled until the food is satisfactory.

Water on the outside of a pot, i.e. a wet pot, increases the time it takes the pot of water to boil. The pot will heat at a normal rate once all excess water on the outside of the pot evaporates.