Leavening Calculator
Chemical leavening is an acid-base reaction, and the arithmetic is in the open: a gram of soda makes a fixed amount of gas, every acid consumes a fixed amount of soda, and a formula is balanced when the two match. Enter what you have and this returns the powder dose for the product, how much soda the recipe's own acids can carry, and the conversion between powder and soda-plus-acid. The chemistry and every figure are in Chemical Leavening.
Acids in the formula
What the numbers rest on
A gram of sodium bicarbonate can release 0.52 g of carbon dioxide, and only if there is enough acid to react with all of it; without acid it decomposes to sodium carbonate and leaves the crumb alkaline. Every leavening acid has a neutralizing value, the grams of soda that 100 g of it will consume, and the acid needed for a given soda is soda × 100 ÷ NV. Cream of tartar and glucono-delta-lactone sit at 45, monocalcium phosphate at 80, sodium acid pyrophosphate at 72.
The dosing bands come from two places. The home rule, from Corriher, is 1 teaspoon of baking powder per cup of flour, 1¼ at most, which is 3.2 to 4 percent by weight, and a quarter teaspoon of soda per cup, about 1 percent, with enough acid to consume it. Gisslen's professional formulas run higher: 5 percent powder in a creaming-method cake, 6 in muffins and biscuits, nearly 7 in pancakes, with buttermilk 2.5 percent powder plus 1.25 percent soda in a cake and 5 plus 1.25 in biscuits; these are fourth-edition print figures. Two experiments bracket the band: pound cake optimizes at about 2.75 percent powder, and a commercial yellow cake peaks at 3 percent soda and collapses at 4.6.
The dairy and cream-of-tartar figures are McGee's rule of thumb, checked against the dairy literature: half a teaspoon of soda per cup of fermented milk, or 1¼ teaspoons of cream of tartar. Cultured buttermilk at about 0.9 percent lactic acid consumes almost exactly 2 g of soda per cup; at the US standard's floor of 0.5 percent it would consume about 1.1 g, and the calculator shows both. McGee's companion figure of a teaspoon of lemon juice or vinegar does not survive the arithmetic: a teaspoon neutralizes only about 0.3 to 0.35 g of soda, and that is the figure used here. Cocoa uses Gisslen's table, 80 g of soda per kilogram of natural cocoa and none for Dutch-process. Honey, molasses, and brown sugar react with soda, but only rough rules of thumb exist for how much, so they are flagged and not counted.
The chemistry, the full neutralizing-value table, and the sources: Chemical Leavening · The leavening line inside a balanced cake: Cake Formula Balancer · Cutting leavening for elevation: Altitude Adjustment