Cake Flour Substitute

Why cake flour is different

Cake flour is milled from soft wheat and has less protein than all-purpose flour, roughly 7 to 9 percent compared with 10 to 12 percent. Less protein means less gluten, which gives cakes, muffins and biscuits a finer, more tender crumb. You can get part of that effect at home by replacing some of the all-purpose flour with cornstarch, which has no gluten at all and dilutes the protein in the mix.

The ratio here takes out two tablespoons of flour per cup and puts in two tablespoons of cornstarch. Sift the two together at least twice, because cornstarch clumps and a thorough mix is what makes the swap work. The result is close to cake flour for most recipes, but it is not identical. Commercial cake flour is often bleached, and the bleaching changes how the flour absorbs liquid and sets the structure, so a very delicate cake, such as an angel food or chiffon cake, may come out slightly different.

Measure by spooning flour into the cup and leveling it, or weigh it, because scooping packs more flour into the cup.

How this calculator works

Each substitute uses a tested ratio: baking powder from cream of tartar and baking soda (2:1), baking soda stepped up to baking powder (1:3, since baking soda is several times stronger), cake flour from all-purpose flour with a portion swapped for cornstarch, and self-rising flour from all-purpose flour with baking powder and salt whisked in.

Where these numbers come from

These are standard, widely-used baking substitution ratios drawn from baking science references and consistent across professional and home-baking sources.

• Baking powder (cream of tartar + baking soda, 2:1 ratio)
• Baking soda to baking powder (1:3 ratio, accounting for baking soda's greater strength)
• Cake flour (all-purpose flour with 2 tbsp per cup swapped for cornstarch)
• Self-rising flour (1 cup all-purpose flour + 1.5 tsp baking powder + 1/4 tsp salt)

Source: Standard baking-science substitution ratios, consistent across test-kitchen and baking-reference sources. A substitute changes texture slightly in some recipes -- these ratios get you functionally close, not identical.