Foods and home making

Experiment 31: To show the effect of hot water on gelatin. (a) Surround the cup containing the gelatin of Experiment 30 with hot water. Then add to the moistened gelatin \ cup of boiling water. Stir until the bits of gelatin disappear. Does hot water dissolve gelatin ? iff) What is the purpose of surrounding the cup containing moistened gelatin with hot water ? Note to the Teacher: The gelatin used in these experiments need not be wasted. By adding 4 teaspoons of sugar, a few grains of salt, and 3 teaspoons of lemon juice, a serving of lemon jelly may be prepared. If you read the directions for preparing gelatin which are printed on the package, you will see that first cold water should be added to the gelatin, then boiling water. From Experiments 30 and 31 you can readily understand that the cold water merely softens the gelatin, i.e., the gelatin absorbs the water, while the boiling water dissolves it. If you taste plain gelatin which has had only water added to it, you will find that, although it is not very pronounced in flavor, it does not taste good. Sugar and fruit juice are needed to give gelatin dishes a pleasant taste. Before adding the sugar and fruit juice to a gelatin dish, one should make sure that the gelatin has been completely dissolved in the hot water. In order to make gelatin mixtures clear, it is advisable to strain them through a cheese cloth. There should be no bits of undissolved gelatin to strain out — merely the bits of fruit pulp which may have been in the juice. Why must gelatin foods be served cold? When gelatin is dissolved in hot water, the mixture looks like plain water. We say it is in the liquid state. The gelatin dishes which we have seen are stiff or solid. In order to change the liquid to a solid, the gelatin mixture must be cooled and chilled. After all the ingredients are added to a gelatin mixture, it is well to cover it and let it stand until it is cool. Then it may be placed in a refrigerator. In cold weather it may be placed outdoors or in a cold cupboard, immediately after it is mixed and covered. 438 Dinner If, after a gelatin mixture has become stiff, it is heated or placed for any length of time in a warm room, it will change again to a liquid. We place a gelatin dish in a cold place to make it stiff and to keep it stiff. It is, of course, the gelatin dissolved in the water that makes the mixture stiffen after it is cold. If some of the particles of gelatin are not dissolved in the hot water, the gelatin mixture may not become stiff enough when chilled. It is for this reason that one should stir the gelatin mixture until every bit of gelatin disappears. In making a small quantity of a gelatin salad or dessert, it is sometimes necessary to surround the dish containing the mixture with hot water while the gelatin is dissolving, just as was done in Experiment 31. What is gelatin? You may have seen some veal broth which had been cooled and chilled. The chilled broth may have been in the form of jelly. As explained on page 363, there is present in bones and other meat tissues a substance which when cooked in water will form gelatin. The gelatin which we buy at market is made from bones and other parts of animals.