Cold water softens and dissolves into itself some of the protein substances, and also soaks out the nourishing qualities of carbohydrates.
These facts are extremely useful in deciding upon the best method of boiling food. For instance, if we have a piece of meat or fish which we wish to boil and serve whole, it should be put into water which is already boiling; this hardens the outside sufficiently to keep the juices inside. This hardening is accomplished in about eight or ten minutes; at the end of that time, the temperature of the water should be allowed to fall a little below the boiling point that the inside of the article may be cooked without being hardened. Water into which fish is put should be just boiling, not rapidly boiling, as the motion sometimes breaks the fish into pieces.
If we wish to make soup, broth, or beef-tea, we cut meat into small pieces and put it into cold water, which is then gradually brought to a high temperature. The cold water dissolves the substances of the meat, which it has a better opportunity of doing from many small pieces than from one large one, and gradually becomes highly and agreeably flavoured. Meanwhile, the meat becomes more and more tasteless and colourless and is, at last, fit only to be thrown away.
Salt is put into the water in which meat is boiled. In cold water it helps to draw out the juices of the meat. In boiling water it draws them out a little, but the heat of the water converts them into a thin albuminous coating for the meat which assists in keeping in the juices.
Nearly all vegetables should be put into boiling water instead of being put on the fire in cold and allowed to come to the boiling point. This is in order that the changes which are made in the cells and fibres may be made at once, before dissolvable substances like starch and sugar are soaked out into the water which is to be thrown away. Some watery vegetables, such as tomatoes and spinach need extremely little water, sometimes no more than adheres to them after they have been washed. These things are really stewed, not boiled. White potatoes should be boiled gently, that the outsides may not break and fall off as they soften.
In most cases, the boiling water in which vegetables are put should be salted, in the proportion of a tablespoonful of salt to two quarts of water. This not only seasons them but makes the temperature of the water somewhat greater. There are some exceptions to this, however; green corn is one of them; salt yellows and toughens it. Many authorities will tell you not to salt peas until they are nearly cooked.
As soon as vegetables are tender they should be drained. Potatoes, whether boiled or baked, should not be covered after they are drained or taken from the oven. They should dry in the air, not soak in their own steam.
Stewing.—Stewing resembles boiling. It is boiling done in the juices of the article cooked increased with a little water. As we wish some of the juices to flow out, we put food to be stewed into cold water. When it has been brought gradually to the boiling point, the heat should then be lowered to the simmering point and the food allowed to simmer for a long while. Stewing is a slow method of cooking but it makes digestible and appetizing meat and coarse vegetables which otherwise would be hard fare. To food which is neither coarse nor tough, it imparts a particularly delectable flavour. Stewed mushrooms are a good example of this.