Starch is good for thickening soups, sauces, and gravies. But it won’t hold baked goods together, and it’s not a good one-to-one substitute for flour in baking. There are four major wheat-free starches you can cook with: corn, arrowroot, tapioca, and potato.
Cornstarch is considered a grain starch, while arrowroot, potato and tapioca starches are considered root starches. Potato starch, tapioca, and arrowroot are larger-grained starches which gelatinize at relatively lower temperatures. Sauces thickened with these starches are more translucent and glossy, feel silky to the palate and have less forward flavors once cooked. These root starches don’t stand up to longer cooking as well as grain starches, so they’re best used to thicken sauces toward the very end of cooking.
Arrowroot flour is ground from the root of the plant and is very useful for thickening recipes. It is tasteless and the fine powder becomes clear when it is cooked, which makes it ideal for thickening clear sauces. It doesn’t mix well with dairy though, as it forms a slimy mixture. It’s recommended that arrowroot be mixed with a cool liquid before adding to a hot fluid. Overheating tends to break down arrowroot’s thickening property.
Tips: Two teaspoons of arrowroot can be substituted for one tablespoon of cornstarch, or one teaspoon of arrowroot for one tablespoon of wheat flour.
Storage: Arrowroot should be kept in an airtight container and stored in a dark, dry, and cool place (no refrigeration is required).
Tapioca starch thickens quickly and at a relatively low temperature. It’s a good choice if you want to correct a sauce just before serving it. It is also a great binding agent when putting together your own favorite gluten-free flour blend.
Storage: Tapioca should be kept in an airtight container and stored in a dark, dry, and cool place. If you want it to keep for long periods of time, store in the refrigerator.
This is a fine white flour made from potatoes, and has a light potato flavor which is undetectable when used in recipes. It’s one of the few alternative flours that keeps very well for long periods of time. Potato starch adds moisture to baked goods and acts as a wonderful thickening agent.
Storage: Potato starch should be kept in an airtight container and stored in a dark, dry, and cool place (no refrigeration is required).
Cornstarch is a medium-sized starch granule that thickens at a higher temperature than root starches. However, once that temperature is reached, thickening happens very quickly! Because cornstarch is almost pure starch, it’s more efficient as a thickener than wheat flour.
Tips: When you want one cup of liquid to be fairly thick, it takes one tablespoon of cornstarch. (A stir-fry sauce might use only one or two teaspoons per cup of liquid). One tablespoon of cornstarch will replace three tablespoons of flour in sauce and gravy recipes.
Storage: Cornstarch should be kept in an airtight container and stored in a dark, dry, and cool place (no refrigeration is required).
Working with starches:
- To avoid lumps, mix the starch with an equal amount of cold liquid until it forms a paste, then whisk it into the liquid you want to thicken. Once the thickener is added, cook it briefly to remove the starchy flavor. Don’t overcook! Liquids thickened with some starches will thin again if cooked too long or at too high a temperature.
- Cornstarch, arrowroot, and tapioca are the most popular starch thickeners. They have different strengths and weaknesses, so it’s a good idea to stock all three in your pantry.
- Starch thickeners give food a transparent, glistening sheen, which looks nice in a pie filling but a bit artificial in a gravy or sauce. If you want high gloss, choose tapioca or arrowroot. If you want low gloss, choose cornstarch.
- Cornstarch is the best choice for thickening dairy-based sauces.
- Choose arrowroot if you’re thickening an acidic liquid. Cornstarch loses potency when mixed with acids.
- Sauces made with cornstarch turn spongy when they’re frozen. If you plan to freeze a dish, use tapioca starch or arrowroot as a thickener.