Does Cornstarch Go Bad?

Cornstarch is one of those household items that most people use only from time to time. At some point, you notice that it’s already past the date on the package and the question “does cornstarch go bad?” becomes relevant.

While cornstarch is only a fine powder made from the starch in corn kernels, there are at least a few questions about it that many people ask. The most common one being if it loses its potency to thicken liquids over time.

If you’d like to know the answer to that question and learn about storage, shelf life and going bad of cornstarch, read on.

Tossed in cornstarch
(credit: Dvortygirl)

How To Store Cornstarch

You should store cornstarch pretty the same way you store wheat flour. That means it should stay in a dry and relatively cool area. The pantry is the best option, but a cupboard in the kitchen will work just as well. At no point there’s a need to refrigerate cornstarch, nor will it benefit from it.

Once you open the package, make sure you keep it tightly closed when not in use. Some brands sell cornstarch in plastic containers, and those containers work great for storing the powder after opening.


If your cornstarch comes in a bag that’s not easily resealable, it’s best to transfer the powder to an airtight container or a resealable pouch upon opening.

Properly sealing cornstarch is vital for several reasons. First, it protects the powder from the outside world, mainly from moisture and any strong odors that might be around. Second, cornstarch attracts pantry pests and insects, and a closed container keeps those at bay.

Garlic wing sauce thickened with cornstarch
(credit: Ginny)

How Long Does Cornstarch Last

Similar to another product derived from corn that is corn syrup, cornstarch has an indefinite shelf life. Unless bugs or moisture gets inside the container, the powder won’t go bad.

Since cornstarch is mainly used as a thickening agent, many people want to know if it loses its effectiveness with time. There are some products on the market, such as baking powder, that don’t go bad but lose their potency with time. Fortunately, cornstarch isn’t one of them, so no need to worry about that when you’re thickening your favorite sauce or gravy for the next meal.

While cornstarch often comes with a best-by date on the package, you don’t have to bother with it if you’re storing it properly. You can easily use it in sauces, stews, and pies, for years to come.


In many recipes, you can substitute wheat flour with cornstarch if the primary purpose of flour is thickening liquid. Cornstarch is better at this so you can get the same results with less cornstarch than flour.

CornstarchStays fine indefinitely
Dusting with corn starch
(credit: Andrew Magill)

Does Cornstarch Go Bad?

As mentioned before, cornstarch doesn’t go bad and doesn’t lose potency with time.

The only “normal” situations when you need to throw it out is when water or bugs get inside the package. Other than that, it will be fine. So if you open the package and there’s mold or any other organic growth inside, discard it. That growth is most likely caused by water.

If the powder seems perfectly fine, it most likely is. If there are some small clumps, it’s okay. You can always sift the powder before using.

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