Does Maple Syrup Go Bad? Yes, Here’s How to Tell

Found an ancient bottle of maple syrup in the back of your pantry or fridge and not sure if you should drizzle it on your pancakes?

Let’s talk about the shelf life, storage practices, and spoilage signs of your favorite pancake syrup.

Maple syrup in hand
Maple syrup in hand

Please note that this article is about pure maple syrup, not imitation maple syrup or any other product that the syrup is only a part of. For such products, read the label carefully.

Does Maple Syrup Go Bad?

Yes, maple syrup goes bad if you store it improperly. Plus, it gradually degrades in quality, so if you store it long enough, eventually, you’ll get to a point where you notice the flavor is not as good as it used to be.

That’s when you should consider opening a fresh bottle of this pancake syrup and tossing the current one.

Let’s talk about the spoilage signs, then.

How to Tell If Maple Syrup Is Bad?

Your maple syrup is bad if:

  • It’s moldy. Your maple syrup can get moldy if any mold spores find their way into the bottle, e.g., if you leave it unsealed for an extended period. And you should discard the product if it has any visible mold on the surface, Vermont Maple Sugar Makers suggest. There’s also an alternative approach that Hillsboro Sugarworks recommends, and that is to skim the top, discard the mold, reheat the syrup to a boil, and then refrigerate it. So while that’s an option, I suggest you go with the former and toss the sauce.
  • It smells off. The smell can be sour (fermentation), yeasty, or simply “funny.” but no matter what it is, if the syrup doesn’t smell like maple syrup, it’s probably gone bad.
  • It tastes bad. If everything else seems okay, but the flavor is terrible, assume the sweetener has gone off and toss it.

That’s about it when it comes to maple syrup spoilage signs. Now, let’s talk about what might seem odd or even alarming but is normal for maple syrup.

Maple syrup mold on the surface

What’s Normal

Your maple syrup is okay if:

  • There’s sediment or crystals at the bottom of the glass bottle. These are maple sugar crystals, and they are harmless. They usually show up if you refrigerate maple syrup for a long time, and they also form if you boil it. You can filter them out using a sieve or strainer if they bother you.
  • It darkens. Darkening is normal, especially if the sweetener sits in storage for a long time.
  • There are white bubbles on top. These are just air bubbles that appear if the syrup has been shaken and are completely safe.
  • Its taste slightly alters. If you store maple syrup long enough, it might lose some of its flavor. That’s expected and nothing to worry about. But if it gets to a point it doesn’t taste all that well, open up a fresh bottle.
Maple syrup white bubbles on the surface

How Long Does Maple Syrup Last?

Maple syrup (Unopened)Best-by + 6+ months 
Maple syrup (Opened) 1+ year

Unopened maple syrup lasts for 6+ months beyond the printed date. Once you open the bottle, your maple syrup should keep for at least a year if you store it sealed tightly and refrigerate it.

(That means maple syrup is quite different from honey, as honey basically can last forever. And even corn syrup lasts longer than maple syrup.)

Of course, these are rough estimates, and different sources have different takes on the subject.

For instance, Hillsboro Sugarworks says that unopened maple syrup basically lasts forever, while according to the USDA, “all maple syrup can be stored in the pantry about a year.”

As usual, the truth is somewhere in the middle.

One thing is sure – unopened syrup lasts for quite some time beyond what’s printed on the label. The worst realistic scenario is that expired maple syrup will taste slightly worse than what you’re used to.

Maple syrup: best-by date highlighted

Do You Refrigerate Maple Syrup?

You can store unopened maple syrup in a cool and dry place. But once you open the maple syrup bottle, you should store the leftovers in the fridge, where they will keep for at least a year.

Yes, you should refrigerate maple syrup after you first open the bottle. That’s because, despite the high sugar content, there’s not enough sugar to preserve the syrup at room temperature.

(That’s unlike other sweeteners, say molasses, that don’t require refrigeration after opening.

Confession time: I used to store opened maple syrup in a kitchen cabinet. That is, until one time, I noticed a nice layer of mold on the surface (see the photo earlier in the article). I’ve refrigerated opened maple syrup ever since.

Maple syrup: refrigerate after opening


If you’ve opened a maple syrup bottle and need to store it for a super-long period, like a few years, you can place it in the freezer.

The liquid won’t freeze because of the high sugar content, so there’s no need to thaw it. In other words, you can use it directly from the freezer.

And if you want to start using it more often, you can simply transfer it back into the fridge and continue using it as usual.

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