Experimental cookery

Conventional method. By the conventional method the fat and sugar are creamed until the mixture becomes lighter in color, spongy and fluffy in texture. Fig. 55 is a photomicrograph of creamed butter and sugar. The irregular, large, and intermediate-sized spheres are sugar crystals with an adsorbed layer of fat. It was difficult at first to decide whether the smaller rounded crystals were air bubbles or sugar. This was determined, as is often the case in experimental work, by accident. In using a microprojector to show slides made from colored creamed fats to a class the heat filter was forgotten. After a few seconds the heat from the light used in the projector melted the fat on the slide. One could watch the air bubbles burst on the screen. The remaining particles after the fat w^as melted were sugar crys- tals. Many of the air bubbles show in the picture as small, white circles with a very light gray line around them, and are hardly discernible at this mag- nification. This strong adsorption of the fat at the surface of sugar crystals and at the interface of air bubbles and a liquid is typical and is one means of distributing the fat throughout the batter. It seems to make little difference in the final product if the fat is stirred for a short period and the sugar is then added gradually, or whether the sugar and fat are combined and then creamed, but air is incorporated more rapidly after the sugar is added. However, creaming by hand is easier and more rapid if the sugar is added graduallv because the mixture is not so stiff. In the conventional method the whole egg is creamed with the sugar and fat or only the yolk is incorporated during creaming and the beaten w^hite is added to the batter. Not as much air can be introduced into the creamed mass if only the yolk is used, but this is compensated for in the cake vol- ume by the air incorporated in the beaten white. Under some conditions there may be advantages in adding the beaten egg white last. Just as good texture is produced if the beaten white is stirred rapidly into the batter as when folded. The texture is also good if the beaten white is added and stirred in with the flour and milk. Considering time, effort, and the cake texture, there is often no advantage in separating the whites and yolks of the egg for plain cake. Fig. 56 is a photomicrograph of the creamed butter-sugar-egg batter after the egg has been added. Since more of the sugar goes into solution the sugar crystals become smaller after the egg is added. Many of the sugar crystals are larger than those shown in this particular field, as will be noticed when the photomicrograph of the batter is observed. METHODS OF MIXING CAKES 483 Fig. 55. — Photomicrograph of thoroughly creamed butter and sugar. The butter is stained and shows black in the picture. Note the rounding of the sugar crystals and adsorption of fat at their surface. Magnification approximately x 100. Mo ' »i^" .. ^.'« i^ s " C i .% .1 -4^^^J^JC Fig. 56. — Same as Fig. 55 after the addition of beaten egg and thoroughly cream- ing. The sugar crystals are smaller due to water from egg partially dissolving the sugar. Note the many numerous small air bubbles. Most of them show white, but many show a thin gray line, which is the fat at the interface of the air, butter- egg-sugar mixture. Magnification approximately x 100. 484