This section is from the book "Experimental Cookery From The Chemical And Physical Standpoint", by Belle Lowe. Also available from Amazon: Experimental cookery.
Fig. 58 is a photomicrograph of the creamed butter-sugar-egg mixture shown in Figs. 55 and 56 after the flour and milk are added. All the photomicrographs are from the recipe in which 1 1/2 cups of sugar were used. The flour and milk were added alternately in thirds, and a total of 225 strokes was used for mixing. In this picture the sugar crystals are shown with an adsorbed layer of fat. In the background are the starch granules of the flour and some very thin films of fat that do not show very well with this magnification. The sugar crystals have a tendency to form in clusters. Fig. 57 shows the cake made by this method. The cakes shown in Figs. 57, 63, and 64 were baked in larger pans than the cakes shown in other illustrations and so cannot be compared on the basis of size. All the ingredients for these cakes were room temperature when mixed. Fig. 59 shows a contrast in creaming to Figs. 55, 56, and 58. The sugar and butter were stirred 10 strokes with a wooden spoon. Then the slightly beaten egg was added and stirred 7 strokes. The flour and milk, Fig. 60, were added in the same manner as for Fig. 58. Fig. 63 shows the cake made from the partially creamed mixture.
Muffin method. By this method the beaten egg, the melted fat, and liquid are combined. All the dry ingredients are combined and added to the liquid ones. The advantage of this method is that the batter can be mixed in a short time. If the milk, eggs, and flour are not cool enough to partially solidify the fat, an oil-in-water emulsion is formed of part or all of the fat, and the texture of the cake is not as velvety, nor is it as tender, as by some other methods of mixing. When an oil-in-water emulsion forms in a batter, the batter remains smooth and does not contain flecks or small curds.
Cake-mixer method. This method has several different names, and as in the conventional method, the manner of adding the milk and flour may vary. As used in the experimental outline the fat has a temperature of 22° to 28°C. It is combined with the sugar and beaten egg. Then they are stirred until thoroughly creamed, spongy, and fluffy. When the beaten egg is added to the fat and sugar at the beginning of the creaming process a rotary egg beater may be used until the mass becomes too stiff to turn the beater easily, when a spoon can be substituted. After the fat, sugar, and egg have been stirred they sometimes separate into fine flecks or curds. The flour and milk are added to the above mixture. Sometimes, after the flour and milk are added to the other ingredients, the flecks or curds may continue or may develop later in the batter. They also usually develop with the conventional method of mixing, and at least in some recipes there is nothing detrimental in their formation. In fact, the presence of very fine flecks seems to give assurance of a good texture in some recipes. If the flecks or curds are very large the texture of the cake is not as good as when they are smaller.
Fig. 59. - Photomicrograph of partially creamed butter, sugar and egg. Magnification approximately x 100.
Fig. 60. - Same as Fig. 59 after the addition of the flour and milk. The irregular grouping of the sugar crystals and gas bubbles is characteristic of the coarser texture obtained in the cake shown in Fig. 63. Magnification x 100.
Fig. 61. - The butter, sugar, and beaten eggs are put in the mixing bowl; then thoroughly creamed. The air bubbles are scarcely perceptible as tiny white dots. Temperature of ingredients 22°C. Magnification approximately x 100.
Fig. 62. - Photomicrograph of cake batter. Same as Fig. 61, after adding the flour and milk. Note the very regular grouping of the sugar crystals. All batters, observed microscopically, that have had regular distribution of the sugar crystals have produced excellent textured cakes. See Fig. 64. Magnification approximately x 100.
Figs. 55 to 64 by courtesy of Lora Ruth James.
James, using Formula 1, found that cakes scored higher when the fat, sugar, and eggs were thoroughly creamed than when only partially creamed.
A variation of the cake-mixer method is to put everything in the mixing bowl at once and then combine the ingredients. The texture of the cake thus obtained for any given recipe depends largely upon the temperature of the ingredients when combined. If all the ingredients are at the optimum or ideal temperature for combining, excellent textures may be obtained. Longer mixing is also required than is usual after the flour is added, if the butter and sugar have not been thoroughly creamed.
Emulsion method. This method of mixing cake is one evolved in the author's laboratory. If an oil-in-water emulsion is desired in a cake batter, why not mix the batter by a method that will give the most stable emulsion? The oil or melted fat is added gradually to the beaten egg exactly as in making mayonnaise. The sugar is added to the emulsion and next the flour and milk. This method of mixing is a poor one for making cake. The cake is more rubbery and tough when mixed by this method. This is logical, for the fat being dispersed in spheres has proportionally less surface area, and being surrounded by the emulsifying agents, the egg and flour, has less shortening power and hence the cake is more elastic and tough. For the same reason the fat is not as evident to the taste as when the cake is mixed by the conventional or cake-mixer methods. If the emulsion breaks, as it often does with the proportion of fat and eggs used in cakes, the texture of the cake is better than if it had not broken. If the temperature of the ingredients is such that the fat does not remain melted, the oil-in-water emulsion is also likely to break. A better texture is then obtained.