Batters are thin mixtures of flour and liquid made in the proportion of one scant measure of liquid to one full measure of flour. If merely mixed and cooked slowly they would be hard and compact. But they are made light by the admixture of air or gas and by quick cooking before the air has a chance to escape.

Air at 70° expands to about three times its volume when exposed to the temperature of a hot oven. So, as the mixture heats in cooking, the expansion of the air in the batter makes it light and porous.

We entangle air in batters by beating the mixture thoroughly, as in whole-wheat gems; by beating air into eggs, and using the beaten eggs in the mixture, as in pop-overs ; and by the air or gas obtained by the union of an acid with an alkaline carbonate, as in the use of baking-powder in the griddle cakes. Sometimes we may use newly fallen snow. The expansion of the snow as it is changed to water, and then to steam, lightens the batter, if used quickly.

As it is important that batters be baked at once before the gas escapes, it is always well to see that the fire is in the proper condition, and to have the pans and ingredients ready before you begin to put the materials together, that there may be no needless delay.

The general rule for mixing all batters is to mix the salt and baking-powder (if that is to be used) with the flour, beat the eggs, add half the liquid to the beaten eggs, and stir this gradually into the flour, then add the remainder of the liquid, beat all thoroughly, and bake quickly. When the expression " beat the eggs separately " occurs in a receipt it means beat the yolks and whites separately.

This lesson illustrates two of the ways of mixing, namely, stirring and beating. Also the simplest way of cooking in hot fat.

Stirring. We stir simply to blend or mix two or more materials. In mixing dry materials, stir or move the spoon round and round in the materials till you cannot tell one from another. In mixing dry materials with liquids, add the liquid gradually, and stir slowly at first to avoid spattering. Be sure that the bowl of the spoon - not the edge nor the tip merely - touches the bottom and sides of the bowl. This is mashing as well as stirring, and the mixture soon becomes a paste. When perfectly smooth, add more liquid till you have the desired consistency. We stir flour and water together for a thickening, and we stir flour and butter and milk for a sauce, but when we wish to add air to the mixture, we beat.

Beating. Tip the bowl slightly, and hold the spoon so that the edge scrapes the bowl, and bring it up through the mixture, and over with a long quick stroke to the opposite side ; under and up through again, lifting the spoon out of the mass, cutting clear through, and scraping from the bottom at every stroke. We beat eggs and batters and soft doughs. The albumen of the eggs and the gluten of the flour, owing to their viscidity or glutinous properties, catch the air and hold it in the form of bubbles, something as we make soap bubbles by blowing air into soapy water. The faster we beat, and the more we bring the material up from the bowl into the air, the more bubbles we have ; but one stirring motion will break them. So in any mixture where we wish to obtain all the air possible we must be careful to beat and not to stir.

Thin batters, like gems made without eggs, and pop-overs should be beaten vigorously just before baking. Batters require to be baked in a hot oven, but if it be too hot, the sudden expansion of the air bursts the bubbles, and the mixture falls.

All the mixtures we are to make to-day are to be cooked in iron or tin, and we grease the dishes to keep the mixture from sticking. The fat on the dish heats quickly, and so helps to cook the outside of the mixture, and this heat gives a flavor and texture to the crust different from those of the inside; and the greater heat of the fat on the hot griddle gives a crust different from that obtained by baking in the oven. There the crust that comes in contact with the greased pan is unlike the top crust which had no fat in contact with it, and all these crusts are unlike that of the steamed pudding, because they have been subjected to greater heat. The brown color and the flavor of crusts are probably caused by the change of some of the starch into dextrine.

Cooking on a greased griddle is a two-sided baking, - first on one side, then turning and baking the other side. It is one form of cooking with hot fat, and from carelessness, too much fat is often used. It is called frying; but true frying is immersion in hot fat. A "well greased griddle or pan " is one greased uniformly, - not a daub here and there, nor masses of grease in the corners, but just a thin coating of fat laid uniformly over the entire surface. Any more fat than enough to prevent the food from sticking is unnecessary, and is absorbed by the food, making it unwholesome.

Very thin batters, or those containing eggs and sugar, require more fat than other kinds; but stiff doughs like pastry and plain cookies often need none.

Suggestion to the Teacher.

In these lessons on batters and doughs the general principles should be clearly explained, for these are really the most intricate forms of cooking. Much depends upon the heat of the oven, and experience is the best teacher in determining this. See " Baking," page 153. The quality of materials will vary, and though definite proportions are given in many of the receipts, the teacher must use judgment, and change them if necessary. See " Boston Cook Book," pages 80 - 107.