Cake flour is the low-protein flour — about 7–9% — finely milled and often bleached. Less protein means less gluten, and less gluten means a soft, tender, fine crumb. It’s the secret behind delicate layer cakes, cupcakes, and tender biscuits, where chewiness would be a flaw rather than a feature.
Why it works
Gluten gives structure and chew — wonderful in bread, wrong in a fluffy cake. Cake flour’s low protein keeps cakes from turning dense or tough, and its especially fine milling helps it absorb fat and sugar smoothly for an even, velvety texture.
Easy DIY substitute
No cake flour on hand? For each cup, measure 1 cup of all-purpose flour, remove 2 tablespoons, and add 2 tablespoons of cornstarch. Sift it together several times to distribute the cornstarch evenly. It isn’t identical to true cake flour but works well in most recipes.
Frequently asked questions
What protein is cake flour? About 7–9% — the lowest of the common flours.
How do I make cake flour? Per cup: 1 cup AP minus 2 Tbsp, plus 2 Tbsp cornstarch.
Why are my cakes dense? Often too much flour or too-high protein — measure carefully and consider cake flour.