Is It Time To Throw Out Your Maple Syrup? Here's How Long It Actually Lasts

I've always kept a bottle of maple syrup on hand for my baking needs. Whether I'm making maple walnut cake, maple pie, or waking up a boring boxed cake mix, I always feel relieved to find that I still have some syrup left. However, the opposite situation rarely occurs. Unless you frequently use it as a substitute for honey or add maple syrup to every meal, you may discover that your bottle lasts for months. In that case, you might find yourself more concerned about whether it's time to throw out that bottle.

The good news is that, under proper storage conditions, your months-old bottle of maple syrup is still fine and can last up to a year before it expires. To maximize its shelf life, store an open bottle in the refrigerator with the cap sealed tightly. Alternatively, you can achieve similar results by keeping it in a cool, dry place, such as a cabinet. If you haven't opened your bottle of maple syrup yet, it can last indefinitely. Just be sure to store it in a dark place, like a cupboard or pantry, away from direct sunlight. For even longer storage, consider placing the bottle in the freezer, where it can last for several years.

Even though maple syrup is guaranteed to last a long time and the label on the bottle indicates you have months before the best-before date, the kitchen critic in you may still want to ensure the syrup is still edible. The most telling sign to look out for is mold. Pure maple syrup is harvested from sap and contains no preservatives, making it prone to spoilage, which manifests as a slimy layer that develops on top of the product. This often occurs when an open bottle of maple syrup is left unrefrigerated; exposure to air and fluctuating temperatures can encourage the growth of yeast and mold spores.

The jury is still out on how to handle mold in your maple syrup. Conventional wisdom suggests scraping off the mold or passing the syrup through a fine sieve to remove the mold layer, then boiling the syrup to kill any harmful pathogens. However, if the syrup tastes bad after these steps, it's best to discard it.

However, a recent study shows that boiling moldy maple syrup does not eliminate microbial growth. This research indicates that some molds in syrup produce mycotoxins that are harmful to consume and cannot be destroyed by boiling. Therefore, if you find mold in your syrup, it's advisable not to simply scrape off the top layer; instead, discard the entire bottle. Additionally, if you notice a sour or fermented odor, an overly thick or slimy texture, or a murky appearance, these are further signs that it's time to throw out your maple syrup.