The following weights for a teaspoon of baking powder have been suggested and used.

Type of powder

Halliday and Noble Grams per teaspoon

Woodruff Grams per teaspoon

Phosphate

4.00

3.52

Tartrate

3.67

3.07

Sulfate-phosphate

3.70

2.85

The weights by Woodruff were determined by finding the average weight of a cup of the powder and taking 1/48 of this for the weight of a teaspoon. From the above weights it can readily be calculated that 3 teaspoons of the sulfate-phosphate powder by the Halliday and Noble scale are equal to about 4 teaspoons by the Woodruff scale. When measured by teaspoons rather than by cups the averages of Woodruff are low.

The weight of a teaspoon of baking powder can vary considerably even when a standard measuring spoon is used. For accurate experimental work the baking powder is weighed, but the housekeeper usually measures the ingredients for her cakes. Dipping the measuring spoon into the can and leveling off the surplus tends to loosen the powder. Thus the weight of the second or third teaspoon of powder will vary, depending on whether it is secured from the loosened or the more compact portions in the can. As the powder stands in the can it tends to become more compact. The averages for about 400 teaspoons of each type of powder, secured by leveling off the surplus powder after dipping the spoon in the can, have been about

3.0 grams for one brand of sulfate-phosphate, about 4.0 grams for a second brand, about 4.0 for the phosphate, and about 3.5 for the tartrate.

Of course the optimum amount of baking powder, in addition to (1) the type of baking powder, varies with (2) the formula, (3) the thoroughness of creaming, (4) the method of mixing, (5) the extent of mixing, (6) the kind of flour used, (7) the technic of the operator, (8) time of adding the beaten egg white, and (9) the altitude.

In general, formulas with high proportions of sugar seem to require slightly more baking powder than those with smaller proportions.

The more thoroughly the butter and sugar, or the butter, sugar, and eggs, are creamed, the more air incorporated and the less baking powder needed. Of course, no more than a maximum amount of air can be incorporated in any given mixture.

Methods of mixing like the conventional-sponge in which a great deal of air is incorporated in the egg-sugar mixture may need slightly less baking powder than the conventional method.

There is a limit to which cake batters can be stirred or beaten without affecting the tenderness of the product. In general, the sulfate-phosphate types can be mixed longer than the other types of powders.

Because of the tenacity of the gluten, more baking powder is needed with bread or all-purpose than for pastry or cake flours.

If the beaten egg whites are added to the batter last, either by folding or stirring, a smaller proportion of baking powder produces a more desirable texture.

As the distance above sea level increases, the atmospheric pressure is decreased. Consequently, because of the reduced pressure, a given quantity of baking powder has greater leavening ability at higher altitudes. Hence a smaller amount of any type of powder is needed at higher altitudes. Peterson has developed recipes for high altitudes.

That baking powder has an effect on the viscosity of the batter is shown clearly by adding varying amounts of baking powder (Experiment 84D) to a particular cake recipe. A much stiffer, thicker batter is secured with the larger quantity of baking powder.

Varying the proportion of egg. With increased egg the cell walls become thinner and the cells smaller and regular in shape as the mixing is continued. When the egg is increased the crumb is very elastic, the cake more rubbery, tough, and compact. Increasing the egg imparts a glaze to the crust, but the appearance is different from, and less crystalline than, that produced with increased sugar. The plain cake recipe with increased egg and no other changes is not so desirable as the original recipe. If egg is increased, a better texture is obtained if the white is beaten separately and added last.

Varying the proportion of sugar. Sugar is added for sweetening. But it also affects the texture of the product. With larger quantities of sugar the batter must be mixed longer even when baking powders that react rapidly at low temperatures are used. The sugar competes with the gluten and other ingredients for the liquid and prevents the development of the gluten so that longer mixing is necessary. When the sugar in the very plain cake recipe is increased from 1 to 1 1/2 cups a sweeter cake is obtained and one with a better-balanced formula, so that a better texture and volume are obtained. The amount of mixing to produce the best texture with 1 1/2 cups of sugar is from 225 to 300 strokes when a tartrate or phosphate baking powder is used, if the powder is added with the flour. When the proportion of sugar is increased to 2 cups, Fig. 74, a decidedly different texture is obtained from that when the flour or egg is increased. With slight mixing the top of the cake is sunken or fallen; see Fig. 74, cake number 1, mixed with 50 strokes, Experiment 84F,4. Sometimes the cake bubbles up over the top of the pan and then falls. The top is rough, shiny, and has a crystalline appearance. The cell walls are very thick and the cells are large and coarse. The cake browns readily. It is gummy and chewy when tasted. As the amount of mixing is increased the texture of the cake is improved. The number of strokes required to produce a fine grain is very much greater than in the plain cake. The texture with 1000 and 1500 strokes, cakes numbers 5 and 6, Fig. 74, is very much better than in the cakes just slightly mixed. The most desirable texture is sometimes obtained with 400 strokes, sometimes with 1000, and occasionally with 1500. The cakes with increased sugar used in the illustrations were made with a tartrate baking powder.

Varying the proportion of fat. Increasing the fat results in a more tender cake. The fat in the plain cake recipe can be increased from 1/2 cup to 3/4 cup and a good texture obtained, but the volume of the cake is smaller. The cake is better if the sugar and eggs are increased at the same time. The appearance of the crust of a cake with a large amount of fat is rather smooth. It browns readily, but not so easily as with sugar.