Cornstarch vs. Flour: How Do They Compare?

Flour is the powdery result of grinding wheat, corn, rice, or seeds (or dried roots like cassava). It’s used in many different culinary applications, from baked goods like breads, cakes, and pie crusts to roux for sauces and airy batters. Most conventional flours are made from wheat kernels (or wheat berries), which consist of an endosperm, a germ, and a bran. It can also be used as a thickening agent and is commonly used to create a roux when combined with fat-based liquids like melted butter.

Cornstarch is a grain starch made from the endosperm of corn grain. Producers soak the corn kernels in liquid and remove the endosperm—the nutrient-rich inner layer of the grain—from the grain, then extract the starch and dry it to form a white, flavorless, and odorless powder. Like potato starch and other root starches, cooks use cornstarch to thicken soups, gravies, and other liquid food items. Often it’s mixed with a lower-temperature liquid—room temperature or cold water will work—to create a wet paste called a slurry.

Corn starch is most often used in cooking as a thickener for pudding, pie filling, stir-fried sauces, or coat fried foods. Cornstarch is gluten-free and has several health and household applications: a paste made from cornstarch may soothe skin irritations, including sunburn, and help remove stains from fabric, while dry cornstarch may relieve fungal itch.

Both flour and cornstarch can be used to thicken sauces or coat fried foods like fried chicken for a crispy exterior. However, cornstarch and flour have different flavors, textures, and thickening properties in the kitchen and should be used for different cooking situations. Here are some of the primary differences between cornstarch and flour.

• Composition: The main difference between cornstarch and flour is how they are made. Cornstarch is a gluten-free, all-starch powder that is always made of the endosperm of the corn kernel. Flour can be made from any kind of grain (including corn) but all-purpose flour is made of wheat (which contains gluten) and is used as the base for most baked goods.
• Flavors: Cornstarch is a mostly flavorless powder that is used mostly to add texture to a dish rather than taste. Flour varies based on the type of grain it is made from, but it generally has a strong, earthy taste with sweet or mild notes.
• Thickening properties: Cornstarch is typically used to thicken liquid-based sauces. Even a half of a tablespoon of cornstarch will thicken a sauce into a translucent, silky slurry in under a minute. Flour’s thickening abilities are much weaker and you will need larger quantities of it to thicken liquids. It also works better with fat-based sauces.

Cornstarch is most often used as a thickening agent to thicken liquid-based sauces. It gives liquids a glossy and thick appearance perfect for gravies or sweet sauces like pie filling. You can use it in reduced stock or in the juice from meat to create au jus gravy. First, dissolve the cornstarch into a slurry in a small bowl with some cold water. Then, add the thick paste to the liquid you would want to thicken. As the cornstarch is incorporated into the sauce, it will thicken into a paste or gravy. If you don’t have cornstarch on hand, you can substitute arrowroot powder, potato starch, and tapioca flour or tapioca starch.

Flour is most often used as a thickening agent for sauces that are fat-based, such as any liquids made from cream, milk, or butter. It is most often used to make roux, which is a gravy made by combining flour and butter. You can use flour to thicken a sauce by mixing the flour first into cold water until it dissolves and then adding it to the liquid you wish to thicken. All-purpose flour, wheat flour, or rice flour are commonly used to thicken sauces.

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