Does Cornstarch Go Bad? How Long Does It Last?

logo by Editorial Staff | Updated on September 30th, 2023

Wondering if that canister of cornstarch at the back of your pantry is still good to use? You’re in the right place. In this detailed guide, we’ll tackle everything you need to know about cornstarch: its longevity, proper storage methods, and how to tell when it’s time to let go. By understanding these nuances, you can make well-informed decisions about using this kitchen staple.

What is Cornstarch?

Cornstarch is a versatile ingredient that originated in 1844 and has been used for various applications since then—from cooking to industrial purposes. Known as corn flour in some places, it is made from corn and is prevalent in corn-growing regions like the United States.

Starch and corn cob on the table

Although it might seem similar to wheat flour, cornstarch is gluten-free, making it a fantastic option for those with gluten sensitivities. Another interesting aspect of cornstarch is its transparency when cooked, which can be important in dishes where appearance matters.

The Multifaceted Role of Cornstarch

Cornstarch is primarily used as a thickening agent in a wide range of recipes, including soups and gravies. To create a thickening slurry, you can mix it with cold water in a 1:1 ratio. Since it comes from corn, it serves as a gluten-free alternative for making a roux and is an effective thickener for gravy. You can even add it towards the end of cooking to adjust the thickness of your sauce or soup.

Cornstarch, Corn Flour, and Cornmeal: What’s the Difference?

It’s easy to get confused with the various corn-derived products on the market. Cornmeal is a coarsely ground product made from corn, while corn flour is a finely ground version. On the other hand, cornstarch is made from just the starch extracted from corn kernels. While cornmeal and corn flour possess a distinct corn flavor, cornstarch is relatively tasteless and mostly serves to thicken recipes.

The Longevity of Cornstarch: An In-Depth Look

You might be surprised to learn that cornstarch has an almost indefinite shelf life, provided it’s stored properly. Because it’s a dry, powdered food with minimal moisture content, it’s not a hospitable environment for bacterial or fungal growth. However, if you do not store it in the right conditions, like sealing the container properly, you might find mold or even ants in it.

Proper Storage Methods for Various Locations

In the Pantry

The best place for storing cornstarch is in a cool, dry pantry or cupboard. Ensure that the container is sealed tightly to minimize the chances of moisture intrusion, which can lead to spoilage.

In the Refrigerator

Though not necessary, you can store cornstarch in the fridge. It won’t extend its shelf life but will keep it cool. Just be cautious, as refrigerators are more humid and could introduce moisture into your cornstarch.

In the Freezer

Like the refrigerator, the freezer isn’t a mandatory storage location for cornstarch. If you do choose to store it there, make sure the container is airtight to prevent moisture from seeping in.

How to Identify Spoiled Cornstarch

Presence of Bugs

If you see small, dark bugs in your cornstarch, it’s a clear sign that it’s time to toss it out. These bugs might carry bacteria or parasites, making it unsafe for consumption.

Mold Growth

Finding mold in your cornstarch is a definite indicator that it’s spoiled. Mold can cause severe health problems and should not be ingested.

Unpleasant Odor

A sour or strong, unpleasant smell is another warning sign that your cornstarch has gone bad. Cornstarch usually has a faint, pleasant corn aroma, so any deviation from this is a red flag.

Sour Taste

Before adding cornstarch to your dish, it’s a good practice to taste a small amount. If it has a sour taste overpowering its natural flavor, it’s best to discard it.

Is It Safe to Consume Expired Cornstarch?

Generally, cornstarch remains effective and safe for a long time if stored correctly. However, if you notice any signs of spoilage like mold, bugs, or an off smell or taste, it’s best to discard it. Consuming spoiled cornstarch can lead to digestive issues and should be avoided.

How to Store Cornstarch Effectively

Storing cornstarch doesn’t require any special conditions. A sealed container kept in a cool, dry place will suffice. If you live in a humid area, take extra precautions to ensure that the container is airtight to prevent moisture from entering.


Cornstarch is a reliable, versatile ingredient that, when stored correctly, has a long shelf life. By paying attention to storage methods and regularly checking for signs of spoilage, you can maximize the use of this kitchen staple. Whether you’re thickening a sauce or making a gluten-free dish, cornstarch is a go-to ingredient that deserves its spot in your pantry.


Editorial Staff

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