Potato Starch vs. Cornstarch: A Comparison of the Starches

Potato starch is a root starch extracted from the cells in a potato’s root tubers, which is the organ responsible for energy storage and reproduction. Starches are odorless, tasteless white powders produced by most green plants, including potatoes, corn, and wheat, and are among the most common carbohydrates in modern diets. Cooks typically use potato starch, which is gluten-free, as a thickening agent for soups, sauces, and stews. However, it is also low in nutrients and can cause digestion problems after initial use.

You can make potato starch at home by soaking grated potatoes in warm water, then extracting the starch from the water, and allowing it to dry and harden before breaking it up with a utensil and grinding it into a powder.

Though potato starch and potato flour both come from potatoes, the latter is from dehydrated and ground potatoes resulting in a thicker powder similar in texture to cornstarch. Potato flour primarily serves as a substitute for wheat flour in baking. However, refrain from using it interchangeably with potato starch because it takes on a sticky, glue-like consistency when used as a thickener.

There are many ways to use potato starch, including:

1. 1. Thickener: One of the primary uses of potato starch is as an additive for various foods. Cooks use it to thicken soups, stews, and gravies and to bind and extend the shelf life of meats and cheeses. Potato starch also adds moisture and texture to cakes, breads, and pasta noodles. Many Asian dishes include potato starch as a crispy coating for deep-frying or thickening sauces.
2. 2. Gluten-free baking: Potato starch is gluten-free and a great substitute for wheat flour in baking, lending a chewy or flaky texture to gluten-free cookies, moisture to cakes, and extending the shelf life of baked goods longer than other wheat flour substitutes.
   
3. 3. Industrial binding agent: Potato starch works for various non-food purposes, including as an adhesive and binding agent in paper and plastic goods and an ingredient to assist in the dissolution and digestion of antibiotics. Since it’s 100 percent biodegradable, certain manufacturers use it to substitute plastic and polystyrene in disposable plates and kitchenware.
4. 4. Substitute for wheat during Passover: Potato starch is a popular substitute for wheat flour or matzo meal during Passover, a Jewish holiday where observers abstain from consuming foods made with leavened grains such as cornstarch, oats, barley, and spelt flour.

There are several substitutes for potato starch in baking, including:

1. 1. Arrowroot: Like potato starch, arrowroot is a root starch derived from several plants from South America and the West Indies, including maranta and cassava, which also produces tapioca starch. Arrowroot starch shares many qualities with potato starch, including a neutral taste and considerable thickening power, making it ideal for sauces and pie fillings. It’s also gluten-free but higher in calories than potato starch.
2. 2. Sweet rice flour: You can make sweet rice flour, or mochiko flour, by milling glutinous rice, also known as sticky rice. The flour’s high starch content adds a chewiness to baked goods and Japanese desserts like mochi. Sweet rice flour is gluten-free and has a mildly sweeter flavor than potato starch.
3. 3. Tapioca starch: Tapioca starch is another root starch derived from the cassava plant. Like arrowroot, it has a neutral taste and thickens quickly, making it a good substitute for potato starch in sauces. However, tapioca starch is lighter than potato starch, so you’ll need twice the amount. Tapioca flour is also essentially identical to tapioca starch. Cassava flour comes from the entire cassava root—whereas tapioca starch involves parts of the root—and is not usable as a substitute for potato starch or wheat flour.

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. The addition of a higher-temperature butter or other fat makes a similar thickener called a roux.

Cornstarch is gluten-free and has several health 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.

Cornstarch and cornflour are often used interchangeably but are distinct products. While both production processes include finely milling corn kernels, cornflour contains the entire corn kernel—the germ and hull—and has more nutritional ingredients than cornstarch. Additionally, cornstarch goes by “cornflour” in the United Kingdom, while cornmeal—a coarse flour made from dried corn—is called “corn flour” in the Southern United States.

There are many diverse ways to use cornstarch:

1. 1. Food additive: You can use cornstarch as a thickener for soups, gravies, meat marinades, pie fillings, and as a batter for Western and Asian fried foods. Manufacturers use it as an anti-caking agent in packages of shredded cheese and powdered sugar. The starch can act as an egg substitute in vegan recipes when mixed with warm water.
2. 2. Relieve itching or rashes: Cornstarch works in many health-related scenarios. A paste made of cornstarch may help relieve the pain and itching of insect bites, diaper rashes, burns, and skin infections. Dry cornstarch can alleviate oily skin, absorb moisture in shoes, and even serve as a dry shampoo.
3. 3. Pest control and stain removal: Cornstarch works as a stain remover for clothes, leather, fabric, and even silverware. It can ward off household pests, clean carpets and windows, and act as a homemade adhesive.
4. 4. Industrial: Companies that manufacture airbags, baby powder, and bioplastics, like drinking straws and food storage bags, often use cornstarch to produce these products. Additionally, cornstarch can strengthen textiles and prevent sticking in medical products like latex gloves. The pharmaceutical industry also adds cornstarch to certain medicine tablets and creams to help the body break down and absorb them.

There are many substitutes for cornstarch, including:

1. 1. All-purpose flour: You can use all-purpose flour as a cornstarch substitute. However, you’ll have to double the amount you use; if the recipe calls for one tablespoon of cornstarch, use two tablespoons of all-purpose flour.
2. 2. Rice flour: Rice flour, made from non-glutinous white or brown rice, also requires twice the amount in recipes when used as a cornstarch substitute. However, it’s odorless and flavorless, so it produces similar results.
3. 3. Xanthan gum: Xanthan gum is a water-binding carbohydrate made from fermented simple sugars. Use it to thicken salad dressings and sauces or as an egg substitute to add stickiness to dough in gluten-free baking. However, use it sparingly as a cornstarch substitute, as too much can result in a slimy texture.

There are several significant differences between potato starch and cornstarch, including:

• Carbs and calories: One tablespoon of potato starch contains 10 grams of carbohydrates, 40 grams, and little else—no proteins, fat, or fiber. A tablespoon of cornstarch contains seven grams of carbohydrates, 31 calories, and one gram of sodium. Beyond that, it has no nutritional value.
• Cooking: Cornstarch can withstand long cooking times and thickens quickly, but high temperatures can cause clumping. Potato starch can handle high temperatures, but not for long. The secret to using potato starch is to add it to the recipe at the end of the cooking process.
• Pure: Cornstarch is pure starch, which means that the body quickly breaks it down into simple sugars after ingestion, causing the pancreas to release insulin. Other pure starches include white rice, dextrose, and instant mashed potato powder.

Become a better chef with the MasterClass Annual Membership. Gain access to exclusive video lessons taught by the world’s best, including Alice Waters, Gabriela Cámara, Niki Nakayama, Chef Thomas Keller, Gordon Ramsay, Yotam Ottolenghi, Dominique Ansel, and more.