Does Cornstarch Go Bad? (2024)

Cornstarch is an essential ingredient in so many dishes, to help crisp meat, stop pie crust from getting soggy, and thicken stews, sauces, pie fillings, gravy, and more. But even then, you might find that you have cornstarch sitting in the back of your pantry for quite a while.

So how long before cornstarch expires? And can you use it past the date marked on the box? Here's everything you need to know about whether (and when) cornstarch goes bad, and how to store your cornstarch so it lasts for as long as possible.

Does Cornstarch Go Bad?

Good news: Cornstarch is one of those baking staples that can last for years and doesn't really expire. If cornstarch does go bad, it's usually because moisture or pests have been able to get to it—and you'll notice it immediately. It may have an off taste or flavor (think sour or "funky"), or an off color.

Cornstarch doesn't lose potency over time, so if your cornstarch looks and smells okay, it's perfectly fine to use well beyond any best by date the manufacturer has posted on the box.

How to Store Cornstarch

Like most other grain-based ingredients (such as wheat flour or grains like quinoa) cornstarch should be kept in a cool, dry, and dark place to extend its life as long as possible. You'll also want to ensure that it's in a tightly sealed container, as mice, insects, and other pests could be attracted to the cornstarch.

In fact, many cornstarch manufacturers now sell cornstarch in a well-sealed plastic container to help you keep any potential pests or moisture at bay. So go ahead and keep your cornstarch in that container or another tightly sealed glass or plastic container if you're keeping your ingredients in a matching set of storage containers.

How to Use Up Cornstarch

Cornstarch is a culinary workhorse that you'll pull out many times—especially in the fall, when it's used to help thicken gravy, pie filling, and other Thanksgiving meal must-haves.

You can use it as an even more effective substitute for flour in recipes that use flour to thicken a sauce or soup (think gravy, mac and cheese, and pot pies). You can cut the amount used by half if you're using cornstarch instead of flour.

To use it to thicken, you'll simply mix the cornstarch in with the liquid you're using (i.e. broth, juice, or melted butter), and let it come to a boil to unlock cornstarch's thickening ability.

But you can also use cornstarch for cleaning, in many of the same ways that you'd use baking soda. It's an effective deodorizer, can be made into a gentle scrub to take care of stains on pots and pans—and it's especially effective at absorbing and removing grease stains.

Using it around the house will help you go through that container of cornstarch quickly—so you won't ever have to worry about whether your cornstarch has gone bad.