Cake flour is made by milling and sifting soft wheat, which means wheat that is low in gluten but not gluten-free.
Fine flour makes soft baked items with a moist, airy texture, great for sponges and snickerdoodles.
Gluten is another word for flour's protein component, which binds items together.
Each kind of flour has a different amount of gluten, which affects the end result in a noticeable way.
Minimal gluten in cake flour enables baked items to rise but not acquire a hard, chewy texture.
Cake flour makes it simpler to make delicate, light desserts. If you're a baker, buy cake flour in addition to all-purpose.