Substituting cake flour for AP flour

In general, what is the effect of using cake flour in place of regular flour? I’ve made cakes with both, but always used whatever the recipe called for. If I switch cake for AP, do I need to use a bit more flour? Does it matter if I’m sifting before measuring? Will the resulting cake be discernibly different?

This is for a chocolate cake, if it makes a difference.

Mmmmmm… chocolate cake…

Cake flour is slightly lower in protein (gluten) than most national brands of AP flour. (Southern flours, like White Lily, are an exception). IMHO cake flour is also a little more finely milled. This makes a more delicate, tender end-product than a higher-protein flour. You can sub AP for cake flour, but you use LESS, not more, and adding some cornstarch also helps with creating a close sub.* For every cup of cake flour called for in the recipe, reduce by 2 Tablespoons. If you can, replace that flour with an equal amount of cornstarch.


*If you are using White Lily, I’d just do a one-to-one sub.