Cornstarch safety feat

How Long Does Cornstarch Last? Can It Go bad?

Being one of the most used and multipurpose products, cornstarch raises many questions. We usually leave the bag of cornstarch in a kitchen pantry for years.

But how long does cornstarch last? Cornstarch has an indefinite shelf life. So long as you store it properly, cornstarch will remain good to use for years until you use up the entire bag. Store cornstarch in an airtight container in a dark, dry, and cool area. The pantry, the cellar, or any kitchen cabinet away from heat will be a perfect storage room for cornstarch.

Keep reading to learn about the storage conditions and shelf life of cornstarch to make the most out of it even if you rarely use it.

Does Cornstarch Go Bad?

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Cornstarch is one of the most versatile ingredients in the kitchen. From baking lighter cakes to thickening sauces and making them glossy, you can use this corn-based product for a range of cooking tasks. It can also work as a substitute for many ingredients. Read our food substitutes section articles about cornstarch as an alternative to Brown Rice Flour, Arrowroot Powder and Tapioca Flour.

But the thing is, in many cases, you need only a small amount of cornstarch. This means that you are likely to buy a bag of it and leave it sitting in your kitchen cabinet for months. You may start wondering if cornstarch goes bad? And if it does, how do you know if it is time to discard it?

Should you take the expiration date on the packaging for granted? No, you shouldn’t. In fact, cornstarch is one of those ingredients the expiration date of which you can ignore.

If cornstarch is stored properly, there is a high chance that it will stay good until you finish it.

Does Cornstarch Lose Its Thickening Property Over Time?

As cornstarch is a thickening agent, you may wonder whether or not it loses its thickening properties with time. Luckily, cornstarch doesn’t lose its properties no matter how long you have been keeping it in your pantry. It is not like baking powder or baking soda that loses its potency if you leave it too long on the shelves.

Even if you use cornstarch that is months old, it will still make your gravies glossy and thick and baked goods tender as ever.

How to Store Cornstarch?

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Tyrone Kidney/


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In terms of storage conditions, cornstarch is similar to flour. What does this mean? It means that you have to store it somewhere dark, cool, and dry. If you manage to provide these conditions, your cornstarch will probably last indefinitely.

Cornstarch can be successfully stored in the pantry or in the cellar. If it is not too hot and humid in your kitchen, you can also store cornstarch in a kitchen cabinet along with other everyday items.

Cornstarch can come in a plastic container or paper packaging. If the original plastic container can be tightly sealed, you can use it to store the cornstarch. Paper or cardboard packaging is not as reliable as it can absorb moisture easily. Additionally, you can’t reseal this kind of packaging.

If your cornstarch comes in such packaging, transfer it into an airtight container with a tightly sealing lid. It is important to close the lid of the container well to not only avoid the contact of the starch with oxygen but also prevent it from getting bugs. Although cornstarch doesn’t typically attract bugs like flour and cereals do, a few of those creatures won’t slip the chance of getting into an open container of cornstarch.

When transferring cornstarch from its original packaging into a container, make sure it is clean and dry. Dryness is key as moisture is one of the few things that can cause this product to go bad.

Although a small amount of water that gets into the cornstarch won’t cause it to go bad as in the case of many other powder products, it is certainly recommended to prevent it.

If you want to store cornstarch long-term, avoid exposing it to humidity and moisture. Don’t let it sit under sunlight. Also, keep the cornstarch away from the oven and any other heat source.

Can You Refrigerate Cornstarch?

Cornstarch is not a product that benefits from being stored in the fridge.

If you have no other place to store it, you sure can. However, you need to make sure that the container of the cornstarch is truly airtight. Otherwise, it will absorb moisture from the air and get all clumpy and even moldy.

We recommend wrapping your cornstarch container with food wrap or putting it into a heavy-duty freezer bag as an extra layer of protection.

With this being said, it is easier to store cornstarch at room temperature. Considering that the shelf life of cornstarch stored in the pantry or kitchen is technically indefinite, there is no point in refrigerating it.

How Long Does Cornstarch Last?

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Africa Studio/


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As you have probably guessed, there isn’t much to tell about the shelf life of cornstarch. It can last forever if stored in an airtight container in a cool, dark, and dry place.

Cornstarch does come with a ‘Best by’ or ‘Use by’ date printed on its packaging. So, why does it have one if it can last indefinitely? The answer is simple. You are not allowed to sell food without an expiration date.

You can ignore the ‘Best by’ or the ‘Use by’ date on cornstarch. So long as it is good, you can keep using it way past the date indicated on the product.

How Can You Tell If Cornstarch Is Bad?


As we have mentioned earlier in this article, cornstarch doesn’t lose its potency over time. Thus, it doesn’t go bad in this respect.

There are two things that can make the cornstarch ‘go bad’ – bugs and moisture.

If you store the cornstarch in a plastic bag with a well-sealing lid, hardly will any insect find its way into it. Cleaning your pantry shelves and kitchen cabinets regularly will also help to prevent bug contamination.

To see if there are any bugs in cornstarch, pour some of it on a plate. Thanks to the white color of cornstarch, it will be easy to see the bugs if there are any.

cornstarch safety moth
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If your cornstarch is contaminated with bugs, discard it.

If there are no bugs in your cornstarch, inspect the texture. When the cornstarch appears too clumpy, it means that it has been exposed to moisture. Moisture and humidity will not only make your cornstarch clumpy but they can also cause it to get moldy. If this is the case with your cornstarch, don’t hesitate to discard it and buy a new bag for your future cooking needs.

A few clumps in the cornstarch are usually not a sign of spoilage. You can sift the cornstarch and get rid of the clumps within minutes. Additionally, clumpy cornstarch will mess up your measurements. A tablespoon of clumpy cornstarch is not the same as a tablespoon of sifted cornstarch.

It is also good to taste and smell cornstarch. Good cornstarch is a bland powder and doesn’t smell like anything. If you notice an off-taste or odor, it is best to discard the cornstarch.

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