Can you keep maple syrup in the refrigerator? (5 Various kinds)

In this brief guide, we will answer the question, can you keep maple syrup in the refrigerator? We will discuss the handling and storage of pure maple syrup as well as discuss ways to store some other kinds of syrup.

Can you keep maple syrup in the refrigerator?

Pure maple syrup should be stored in the refrigerator to keep it fresh for a year. If you do not store pure maple syrup in the fridge, it will go bad soon enough if it does not come with added preservatives.

Maple syrup, when unopened, will stay shelf-stable for up to a year. Once the bottle is opened, it will need to be put in the refrigerator, otherwise, it will spoil within weeks.

Some food experts suggest refrigerating maple syrup even if the bottle is unopened. If the syrup comes in a plastic bottle, it is best to transfer the contents to a glass one. 

The main culprit that aids the spoilage of syrup is oxygen. Air brings oxygen to the syrup causing oxidation and speeding up the spoilage.

Once maple syrup spoils, it takes on a hazy texture and starts to grow mold. The low temperature of the refrigerator and the airtight glass bottle preserves maple syrup for a long time.

Maple syrup that is not pure varies greatly from its counterpart. Otherwise known as table syrup, this kind of maple syrup need not be put in the refrigerator. Table syrup is rich in starches and sweetness, hence it is not easy to spoil and stays stable at room temperature. (1,2)

Why does maple syrup spoil?

Maple syrup spoils when bacteria thrive inside the bottle, even when refrigerated. Mold growth and spoilage can occur despite refrigeration. Contamination can lead to various forms of defective sap, resulting in lower quality syrup. Fungi can contaminate syrup regardless of its sugar content.

To ensure proper storage, it is recommended to use a glass bottle with a tightly sealed lid. Air, time, and the environment are common adversaries for all food items, including maple syrup. 

Air introduces bacteria to the syrup, and over time, these bacteria multiply, form colonies, and produce toxins, rendering the syrup unfit for consumption.

Improper sterilization of containers can contribute to bacterial or fungal contamination, impacting the syrup’s chemistry and resulting in changes to color and flavor.

While some individuals suggest straining and reboiling maple syrup to salvage it, this is not a recommended practice. In certain cases, mycotoxins may be present, potentially causing toxicity. 

Therefore, it is crucial to prioritize container sterilization and adhere to good manufacturing practices to minimize the risk of contamination and maintain the quality and safety of maple syrup. (1, 3)

What are the signs of spoiled maple syrup?

The primary indicators of maple syrup spoilage include the presence of mold, off odors, and off tastes.

Mold growth on the surface of maple syrup serves as a clear sign of product defect. Although mold spores are heat-resistant, the extensive evaporation process during syrup production generally eliminates fungal contaminants effectively. 

Therefore, the presence of any mold in maple syrup is likely a result of improper sanitation, low bottle filling temperature, or inadequate adherence to good manufacturing practices.

An effective way to assess the freshness of maple syrup is to give it a sniff. If you detect an unpleasant aroma, such as a sour or yeasty smell, it is advisable to discard the syrup to maintain its quality.

If the taste of the maple syrup does not match its expected flavor, it is recommended to discard it due to quality reasons. Unpleasant or off flavors may indicate spoilage or degradation of the syrup. (3)

What other changes can occur during fridge storage?

When stored in the refrigerator, syrup can experience various changes. If maple syrup is kept in plastic containers, it becomes prone to darkening over time. The darkening process is caused by oxygen permeating through the plastic, which leads to the oxidation of the syrup.

Moreover, if the container is not adequately sterilized, it can become susceptible to bacterial or fungal contamination. Such contamination can affect the chemical makeup of the syrup, causing alterations in its color and/or flavor, even before reaching the point of spoilage.(1, 3)

What are the health effects of consuming spoiled maple syrup? 

Consuming spoiled maple syrup can result in food poisoning and pose various health risks. Symptoms of food poisoning commonly include headaches, vomiting, stomachaches, and diarrhea. 

Loss of appetite and feelings of nausea may also be experienced. Typically, these symptoms should subside within a day or two. However, if they persist beyond this timeframe, it is advisable to seek medical attention.(4, 5)


In this brief guide, we answered the question, can you keep maple syrup in the refrigerator? We discussed the handling and storage of pure maple syrup as well as discussed ways to store some other kinds of syrup.


  1. Mary Lynn Whalen and Maria Franca Morselli. Fungi Associated with Pure Maple Syrup Packed at the Minimum Recommended Reheating Temperature. Journal of Food Protection,47, 688-689, 1984.
  2. U.S. Department of Agriculture. Website. Washington, DC. How long can you keep maple syrup?.
  3. Perry Jennifer J. A Comprehensive Review of Maple Sap Microbiota and Its Effect on Maple Syrup Quality. Food Reviews International 38, 2022.
  4. BM Lund, SJ O’Brien, Public Health Measures: Food Safety in Hospitals and Other Healthcare Settings, Encyclopedia of Food Safety, Academic Press, 2014, 140-148.
  5. Food Safety