Cake Flour
What it is
The lowest-protein white wheat flour, exceptionally fine and soft, often bleached to a bright white.
How it's made
Milled from soft wheat and ground very finely, then typically chlorine-bleached. Bleaching is not cosmetic here: chlorine treatment lowers the flour's pH, weakens the gluten further, and alters the starch so it absorbs more liquid and sugar — which lets a high-ratio cake hold more sugar and fat without collapsing.
Flavor profile
Neutral, with a faint chemical note in some bleached products. Texturally it is silk.
Culinary uses
Tender, fine-crumbed cakes: angel food, chiffon, classic layer cakes. At ~6–8% protein it forms minimal gluten, so the crumb stays delicate. It can do tenderness and lift; it cannot do chew or structure — a bread made from cake flour would be a sad, crumbly thing.
Regional variations
A common DIY substitute is AP flour with a portion replaced by cornstarch, which dilutes the protein but does not replicate the chlorination, so results are close but not identical.
Cultural & historical context
Cake flour rose with the American "high-ratio" cake of the early-mid 20th century — cakes with more sugar than flour by weight, a feat of food chemistry impossible without specially treated low-protein flour.
Reference notes
Tags: `wheat`, `contains-gluten`, `low-protein`, `tender-crumb`, `bleached`. Related ingredients: [Pastry Flour], [All-Purpose Flour], [Cornstarch]. Related cuisines: American. Suggested links: → High-ratio cakes, → Bleaching & flour chemistry.