Does Cornstarch Go Bad? Everything You Should Know

Cornstarch is a fine powder derived from corn kernels, and it is often used as a thickening agent in cooking and baking. People often wonder if cornstarch goes bad, so here goes:

Cornstarch does go bad when it gets wet or humid, and when this happens, molds will soon find their way. A pest infestation can also spoil cornstarch. You should properly store your cornstarch to prevent these external forces. 

Continue reading to learn more about cornstarch shelf-life, storage, and spoilage.

How long does cornstarch last?

Most starch products often come with a sell-by or best-by date, and cornstarch is no exception. However, you can ignore this date as long as you store your cornstarch properly. 

This is to say that cornstarch has an indefinite shelf life, making them the perfect starch product to purchase for long-term use. 

While this means that you can use cornstarch past its expiration date, you must ensure to store them correctly if they must serve you for years to come.

How to store cornstarch properly

Like every other starch, don’t expose cornstarch to moisture or any ambient humidity in the air. Once opened, keep them tightly closed or sealed when not in use.

If your cornstarch comes in plastic containers, leave them safely in their containers and place them in a pantry or an isolated cabinet. If you purchase cornstarch in a non-resealable bag, transfer the powder to an airtight container or ziplock bag upon opening.

Below are some tips to help you preserve your cornstarch properly.

Tips for storing cornstarch

  • Store cornstarch in cool dark areas. Keep them away from direct sunlight. You can store your cornstarch in the dark corners of your pantry.
  • Don’t expose your cornstarch for too long. By all means, keep moisture away from your cornstarch.
  • Keep cornstarch away from high temperatures or extreme heat. Do not place the containers or bags next to a stove or cooker.

How to tell if cornstarch has gone bad

Cornstarch has an indefinite shelf life and thus can always be used. However, they become unfit for consumption when infested by pests. When this happens, cornstarch will go bad.

Additionally, if water or any liquid gets into your cornstarch container, you may find mold or other nasty growths developing, making them unhealthy for the body.

If your cornstarch only has lumps with no signs of mold or bacteria, you can still use it. But note that the lumps are an indication that the powder is exposed to moisture. In this case, stir up the cornstarch or sift it before adding it to your sauce.

Find below some other ways to tell if your cornstarch is good or bad.

The appearance of bugs

Bugs are the commonest sign that your cornstarch is bad. When you spot these tiny insects in your starch, it has gone bad.

You may want to remove the bugs and use the powder, but remember that their larvae or eggs may still be left in your cornstarch as these are tiny and not easily detectable. Hence, it is best to trash your bug-infested cornstarch.

Bad smell

Cornstarch usually has a fragrant corn smell, but spoilt cornstarch will smell sour, with a strong and unpleasant smell.

Sour taste

The taste of raw cornstarch is another indication of spoilage. Bad cornstarch will taste sour.

Side note: It is best to always taste cornstarch before adding them to your soup or sauce. 

What can I do with bad cornstarch?

If you’re wondering what to do with spoilt cornstarch, here are some suggestions for maximizing your spoilt cornstarch.

  • Use as dry shampoo.
  • Use as a makeshift deodorant.
  • Use in a bleach pen.
  • Untangle knots.
  • Get rid of oil stains.
  • Clean stuffed animals.


How long does cornstarch last?

Cornstarch has an indefinite shelf life.

Does cornstarch spoil?

Cornstarch does not spoil and can be used past its expiration date. But, if you discover mold or any other growth inside it, dispose of it as your cornstarch has gone bad.

Does cornstarch lose its thickening power over time?

Unlike other baking agents, such as baking powder, cornstarch does not lose its thickening ability.

Does cornstarch get bugs?

All kinds of dry goods can attract bugs and weevils, and cornstarch is no exception. 

Discard your cornstarch if you notice any pests inside.

What happens if you eat bad cornstarch?

Nothing will likely happen if you eat cornstarch past its expiry date. They will only be harmful if there is mold or insects in the starch. In that case, you can get digestive disorders such as flatulence or diarrhea.

Can I store cornstarch in the refrigerator?

It is unnecessary to put cornstarch in the fridge as this will neither improve nor decrease its shelf life.

How do I store cornstarch long-term?

The best method for preserving cornstarch long-term is to repackage it into airtight containers or keep them in its original container. Also, store your cornstarch in a cool dark place, away from moisture.


As you have seen from this article, cornstarch does not expire or lose its potency, but this is subject to your storage technique. 

Never leave your cornstarch open for long to avoid moisture from getting into them. Additionally, ensure to keep them tightly sealed when not in use. 

Although you can consume cornstarch past its expiration date, discard them if you notice any foul smell or taste, as this is a sign of a bug or bacteria infestation. 

Precious Uka

Precious is a vast researcher and has a knack for writing. She is also passionate about learning and personal development. She is a graduate of Human Anatomy and is given to helping people live a healthier and happier life.

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