corn syrup shelf life

Corn Syrup Shelf Life: Can It Go Bad?

In the middle of cleaning, you find half-opened corn syrup in the back of your pantry shelf. It looks old and a little dusty. Perhaps, it’s been left untouched for months, which you don’t remember exactly.

You’re thinking of using the syrup for pancakes, or maybe pecan pie. However, you doubt if the syrup is still safe to use. Does corn syrup go bad? How long can you keep corn syrup? How do you know if corn syrup has gone bad?

It’s dilemmatic when we find back forgotten food items in the kitchen. You are strongly against creating food waste, but at the same time, you also don’t want to risk your health.

We’ve all been in such a difficult situation. Keep reading to find useful knowledge on corn syrup’s shelf life, its storage, and how to tell if corn syrup goes bad. If this is what you’re looking for, read on!

How To Store Corn Syrup

Corn syrup (also widely known as glucose syrup) is a type of sweetener made from corn starch. Corn syrup is available in both dark and light varieties.

This liquid sweetener performs well in preventing sugar crystallization. Therefore, corn syrup is widely used for baking and candies recipes.

Storing corn syrup is simple and straightforward, pretty much similar to other sweeteners such as maple syrup or golden syrup. Corn syrup is shelf-stable that keeps well at room temperature⁠—before and after opening.

Pick a dry, cool area, out of the heat and lights. Your pantry is preferable, but a kitchen cupboard is a great option too.

Refrigeration after opening is not necessary. In lower temperatures, the syrup tends to thicken and becomes less pourable. Either way, make sure to close the seal tightly after use, to keep contaminants at bay.

How Do You Tell If Corn Syrup Is Bad?

As you’ve probably guessed, corn syrup doesn’t necessarily go bad as fresh produce does. Sugar, as the main component of corn syrup, inhibits bacterial growth.

As long as corn syrup is stored under ideal conditions and you don’t leave the bottle open for days, the chance of going bad is very unlikely.

However, that doesn’t mean that the quality stays the best forever. That’s why the producer stamps a “best by” date on the packaging.

Corn syrup tends to get darker in color as time goes by. If you have a bottle of corn syrup opened for years, you may notice a change in color or flavor.

Although these changes are not indications of spoilage, it’s up to you to keep it or toss it. Give it a taste test to decide if it’s still worth keeping.

If you think that corn syrup smells off, or something peculiar is floating in the bottle, better to discard it. Perhaps you left it open for too long that bugs or other contaminants made their way into the container.

How Long Does Corn Syrup Last?

Corn syrup keeps well very long, if not indefinitely, as cited from Karo Syrup.  Given proper storage, corn syrup stays safe for years⁠—no matter opened or unopened.

Still, producers provide a “best by” or “use by” date on the label. Again, this is not a safety date. This date is to indicate a period when corn syrup retains its peak quality.

Although it keeps safe indefinitely, corn syrup may degrade in quality, such as in color or flavor. USDA recommends keeping it for 3 years in the pantry for its best freshness and quality. (*)

Corn syrup typePantry
Corn syrup (unopened or opened)Keeps safe indefinitely; for best quality keep for 3 years in the pantry

This table is for a rough estimate for the best quality. The actual shelf life mostly depends on storage conditions. It’s always worth checking before use, especially for old syrup.


What are healthier substitutes for corn syrup?

Some corn syrup alternatives that you can find from your pantry include golden syrup, honey, white sugar, or agave nectar.

What is the difference between corn syrup and High-Fructose Corn Syrup?

Corn syrup is often mistaken for High-Fructose Corn Syrup (HCFS). Both are indeed processed from cornstarch, but these two are different products. The latter undergoes further enzymatic reaction to convert glucose into fructose, which makes the syrup sweeter. (*)

What is the difference between dark corn syrup and light corn syrup?

Both are prepared with mostly similar ingredients. The dark one is added with refiner’s sugar (a type of molasses) that gives it a dark appearance and a more robust flavor. Light corn syrup is moderately sweet and typically added with vanilla extract.

Is it safe to use expired corn syrup?

Regardless of a slight change in quality, corn syrup is safe to use for an indefinite time when stored properly. Make sure you check it before use in case filthy contaminants get into the bottle.

Final Thoughts

Corn syrup is a liquid sweetener prepared from corn starch. With proper storage, it keeps for years, if not indefinitely. Although it remains safe to use, the quality may slightly change as it ages.

Corn syrup keeps well at room temperature at all times. Refrigeration is not required. On the contrary, refrigeration thickens the consistency and makes it difficult to pour. Close the seal tightly after each use.

If you have old syrup, it’s always worth spending extra minutes to check if it’s good to use. In case you find something strange floating in the bottle or off smell, better discard the syrup.

Don’t forget to check our article to find the right substitute for corn syrup that works great for your recipe.

corn syrup goes bad

*Photo by AllaMachutt/depositphotos

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