No Cornstarch? Here's What to Substitute
Let's say you're standing at the stove-top, making banana pudding, or some sausage gravy, or a stir-fry sauce. It's all coming together nicely, but you need to thicken things up. Enter cornstarch. This pantry staple makes thin liquids rich and smooth without changing their flavor. It also adds an attractive glossy sheen—a bonus when you're making a fruit pie filling or a buttery pan sauce. And it's gluten-free!
All you have to do is make a slurry—cornstarch and cold water mixed until completely smooth—then add it to the recipe. Typically you'll need 1 tablespoon cornstarch to 1 tablespoon cold water for each cup of liquid. A slurry prevents lumps from forming in your recipe. Stir into the hot sauce until the liquid thickens and starts to bubble, then continue cooking for one more minute to make sure the cornstarch is completely cooked.
But what if you are completely out of cornstarch? Don't fear, there are other options.
Chances are, you have all-purpose flour in your pantry. Flour makes a fine thickener, although you must treat it a little differently from cornstarch. Unlike cornstarch, flour doesn't make sauces more glossy, and if not cooked completely, can slightly change the flavor of a dish.
You'll still want to make a slurry: The ratio is two tablespoons flour and ¼ cup cold water for each cup of liquid. Once you add the slurry to the hot sauce, stir until the mixture turns thick and bubbly. Continue cooking two to three more minutes to make sure the flour is cooked and doesn't have a "raw" taste.
Instant flour such as Wondra also works well as a thickening agent. Because this flour is extra-fine you don't have to cook it as long; it will dissolve quicker than all-purpose flour.
Tapioca, Arrowroot, or Potato Starch (or Flour)
Although you may not have these flours on hand, they all make a good gluten-free replacement for cornstarch. (Bob's Red Mill makes all three.) They can't be used exactly the same way, though. Potato starch is good for high-heat cooking, like baking Substitute two tablespoons tapioca starch for one tablespoon cornstarch. Use an equal amount of arrowroot or potato starch for cornstarch.