Bakers often use cornmeal in breads and muffins to add nutrition and bulk. It's also gluten-free, making it appealing for those allergic to gluten and wheat. The meal itself is dried, coarsely ground corn kernels, though both polenta and grits are coarser in texture. Cornmeal feels a bit like sand if you rub it between your fingers. It comes in white, yellow and blue varieties depending on the kind of corn it comes from.
Corn flour is a finer version of cornmeal. It feels just like wheat flour when pinched between your fingers and comes in white, yellow and blue just like its coarser cousin. If you find yourself making a recipe calling for cornmeal and you only have corn flour, you can substitute with a little consideration.
Read your recipe carefully to see what the cornmeal is used for. If the recipe needs cornmeal to add bulk and density to the recipe, substitution with corn flour is not recommended. If the recipe isn't contingent upon texture or the cornmeal is to reduce dough stickiness, substitution is highly possible.
Replace the cornmeal in your recipe with the same amount of corn flour. For example, if your recipe calls for 1/3 cup cornmeal, add 1/3 cup corn flour instead. Be aware that your recipe will be lighter, fluffier and less dense than it would be with cornmeal. The batter or dough will also be slightly thinner.
Bake your recipe for less time. Since the flour is less dense it needs less time to cook through. Decrease the baking time by half at first, and check the item with a toothpick. If the toothpick comes out doughy, bake the item for an additional 10 minutes at a time until the toothpick comes out clean.
Sprinkle corn flour liberally onto a cutting board or into a cake pan in place of cornmeal. Since the texture and amount don't matter in these cases, use as much as you need to coat your board or pan completely in a thin layer of flour. Proceed normally with the rest of the recipe.