All-purpose flour can replace cake flour, but your baked goods will be denser and tougher
Yes, you can bake with all-purpose flour when you don't have cake flour on hand. The result will still be edible and reasonably good. But the texture will be noticeably different—cakes will be less tender, cupcakes will crumb more when you cut them, and cookies may spread less evenly. This happens because cake flour and all-purpose flour have different protein content, and protein directly affects how much gluten develops when you mix and bake.
The difference matters most in delicate cakes where texture is the whole point—a vanilla layer cake, a chiffon cake, an angel food cake. It matters less in heavily spiced cakes, chocolate cakes, or anything with frosting thick enough to hide the crumb. If you're baking a sheet cake for a potluck, all-purpose flour will work fine. If you're making a wedding cake, the swap will show.
Key Takeaways
- Cake flour has about 7 to 8 percent protein; all-purpose flour has 10 to 12 percent, which creates more gluten and a tougher crumb.
- You can soften all-purpose flour by replacing 2 tablespoons per cup with cornstarch, which lowers the effective protein content.
- The swap works best in chocolate cakes, spiced cakes, and anything with thick frosting, and worst in white cakes and sponge cakes.
- Cake flour is inexpensive and keeps for months in a sealed container, so buying a small bag is often easier than substituting.
Why the protein difference matters in baking
When you mix flour with liquid and stir, the proteins in flour bond together and form gluten. Gluten is what gives bread its chew and structure. In cake, you want less gluten, not more, because gluten makes the crumb tight and tough instead of tender and light.
Cake flour is milled from soft wheat and contains about 7 to 8 percent protein. All-purpose flour is milled from a blend of hard and soft wheat and contains 10 to 12 percent protein. That 2 to 4 percent difference sounds small, but it changes how much gluten develops and how the cake rises. A cake made with all-purpose flour will have a denser, more compact crumb and may dome or crack on top more easily.
The difference is most obvious when you compare the two side by side. A white cake made with cake flour will be pale, fine-crumbed, and almost fluffy. The same recipe made with all-purpose flour will be whiter (because less gluten means less browning), slightly drier, and noticeably more compact.
How to modify all-purpose flour to act like cake flour
If you want to use all-purpose flour and reduce the toughness, you can lower its protein content by swapping out some of the flour for cornstarch. Cornstarch contains no protein and no gluten, so it dilutes the flour's strength without changing the total volume of dry ingredients.
For every cup of cake flour a recipe calls for, measure out 1 cup of all-purpose flour, remove 2 tablespoons, and replace those 2 tablespoons with cornstarch. Sift the two together several times to blend them evenly. This mixture will not be identical to cake flour—the protein will still be slightly higher—but it will be much closer than all-purpose flour alone, and the difference in the finished cake will be small enough that most people won't notice.
Some bakers use arrowroot powder or potato starch instead of cornstarch. All three work the same way: they dilute the protein without adding gluten. Cornstarch is the most common and the easiest to find.
Which cakes tolerate the swap best
Chocolate cakes are the most forgiving. Cocoa powder itself is low in protein and adds flavor and color that mask a slightly denser crumb. A chocolate layer cake made with all-purpose flour will taste and feel almost identical to one made with cake flour.
Spiced cakes—carrot cake, pumpkin cake, gingerbread—also hide the texture difference well because the spices and mix-ins (nuts, fruit, oil) already make the crumb less delicate. Coffee cakes and sheet cakes are similarly forgiving because they're meant to be casual and sturdy.
White cakes, vanilla cakes, sponge cakes, and chiffon cakes are the hardest to swap. These rely on a tender, fine crumb to be good, and all-purpose flour will make them noticeably tougher. If you're making a white wedding cake or a delicate vanilla layer cake, it's worth buying cake flour or using the cornstarch modification.
What happens if you use all-purpose flour without modifying it
Your cake will still bake. It will still taste good. But you may notice one or more of these changes: the cake will be denser and less fluffy, it will crumb more when you cut it, it may dome or crack on top, and it may be slightly drier even if you don't overbake it.
The rise may also be slightly less dramatic. Because all-purpose flour develops more gluten, the batter sets faster during baking, which can trap steam and prevent the cake from rising as high. This is usually a small effect—you won't end up with a pancake—but it's noticeable if you're comparing two cakes side by side.
Frosting and filling can mask many of these issues. A cake that's slightly denser but covered in thick buttercream will taste fine and look fine. A naked cake or a cake with a thin glaze will show the difference more clearly.
When to buy cake flour instead of substituting
Cake flour is inexpensive—usually $2 to $4 for a 2-pound bag—and lasts for months in a sealed container in a cool, dry place. If you bake cakes regularly, buying a small bag is often easier and more reliable than measuring out the cornstarch swap every time.
Cake flour is sold in the baking aisle of most grocery stores, near the all-purpose flour. It's also available online. Some stores carry store-brand cake flour, which is identical to name-brand flour and costs less.
If you only bake cakes occasionally, the cornstarch swap is fine. If you bake cakes weekly or make delicate cakes often, a bag of cake flour in your pantry will save you time and give you better results.
Other flour swaps that work in cakes
If you don't have cornstarch, you can use a small amount of other low-protein ingredients to dilute all-purpose flour. Potato starch, arrowroot powder, and tapioca starch all work the same way. Use the same ratio: 2 tablespoons per cup of flour.
You can also use pastry flour if your store carries it. Pastry flour has about 8 to 9 percent protein, which is between cake flour and all-purpose flour. It won't be as tender as cake flour, but it will be noticeably better than all-purpose flour alone, and you won't need to modify it.
Avoid using bread flour or whole wheat flour as a substitute. Bread flour has even more protein than all-purpose flour and will make the cake tougher. Whole wheat flour has a different flavor and absorbs more liquid, so it requires recipe adjustments.
Frequently Asked Questions
Will a cake made with all-purpose flour still rise?
Yes, it will rise, but usually not quite as high or as evenly as one made with cake flour. The extra gluten in all-purpose flour can set the batter faster, which traps steam and sometimes causes doming or cracking. The cake will still be a normal height—just slightly less fluffy.
Can I use all-purpose flour for cupcakes?
Yes, with the same trade-offs as cakes. Cupcakes made with all-purpose flour will be denser and may crumb more when you bite into them. The cornstarch swap works for cupcakes too, using the same 2 tablespoons per cup ratio.
Does the cornstarch swap work for brownies or cookies?
Brownies and cookies are less sensitive to the flour swap than cakes are. Brownies are meant to be dense, so all-purpose flour works fine without modification. Cookies may spread slightly less, but most cookie recipes are forgiving enough that you won't notice a big difference.
How long does cake flour last once opened?
Cake flour lasts about 6 to 8 months in a sealed container in a cool, dry place. Store it in an airtight container or a resealable bag to keep out moisture and pests. If it smells off or you see any discoloration, throw it out.
Is self-rising flour the same as cake flour?
No. Self-rising flour is all-purpose flour with baking powder and salt already mixed in. It has the same protein content as all-purpose flour, so it won't give you the tender crumb of cake flour. Use it only in recipes that specifically call for it.