Does syrup go bad? (+3 Ways to tell)

In this article, we will answer the question “Does syrup go bad?”, and how to tell If Maple syrup is bad?

Does syrup go bad?

Yes, maple syrup can go bad. It may be caused by physical contaminants like minerals, wood chips, dust, or ash or due to microbes like yeast and fungi. Maple syrup doesn’t expire. If stored correctly, It can be kept for an indefinite period. 

How to store maple syrup?

An unopened bottle of maple syrup should be stored in a dry, dark, and cool area away from heat sources like sunlight and stovetop. The pantry and the kitchen cabinet works fine.

After opening the bottle, you need to make sure It is tightly sealed and refrigerated at all times. It is because natural maple syrup does not have added preservatives.

If you opened the bottle but you feel like you do not use it much and are looking for long-term storage, freezing is the way to go.

Grab a freezer-safe plastic or container and pour the maple syrup into it. Leave 1-inch headspace to allow the syrup to expand during freezing.

Alternatively, pour the syrup into an ice-cube tray. This allows you to thaw as much syrup as you want.

However, maple syrup is quite shelf-stable so It won’t require freezing. Because you would have finished the bottle before the syrup undergoes the quality deterioration process.

The shelf-life of syrup

The following table shows an estimated shelf-life of different types of syrups under varying storage conditions.

In the pantry In the fridge 
Maple syrup (Unopened)Indefinitely 
Maple syrup (Opened)More than a year 
Pancake syrupIndefinite —-
Corn syrup Indefinite —-

How to tell If maple syrup is bad?

Sediment at the bottom of the bottle of maple syrup is natural. It is not an indication of spoilage. It just means the syrup was not filtered properly after boiling. The sediments are the sap minerals. The same applies to If the syrup looks a bit hazy.

Other than that sugar crystallization is a common problem in maple syrup due to frequent heating. It could be fixed by adding a splash of water to the syrup and warming it in a hot bath. Do not boil. Because the sugars will become supersaturated if too much thickened leading to crystallization.

Mold growth 

The presence of mold is a clear indication of spoilage. While you can remove the moldy part and boil the rest and use the rest of the syrup with satisfaction, that’s not recommended and thats’ not how It’s done. 

The heating will kill the vegetative fungal cells but the spores and the toxins will survive making the syrup unsafe for consumption.


You can quickly judge the syrup for freshness by giving it a sniff. If there is something off about it, get rid of the maple syrup. It might give off a sour or yeasty smell.


If the syrup does not taste as It should, you can discard It for quality reasons.

Other FAQs about Syrup which you may be interested in.

Can syrup go bad?

Does corn syrup go bad?

Sugar as a preservative 

Maple syrup is shelf-stable and that stability comes from the high content of sugar. The sugar acts as a preservative and inhibits microbial growth.

Microbes need water to carry out enzymatic reactions important for their growth. When maple syrup is boiled, water evaporates. The water that is left behind is bound with the sugar. The high solubility of sugar in water takes up all the water molecules, leaving behind none for the microbes.

As long as the bottle of the maple syrup is unopened, the microbes can’t grow in it. Once the bottle is opened, it starts to pick up moisture from the surroundings. The moisture settles as free water in the syrup and is available for microbial growth.

Food safety in the syrup making process 

Maple syrup is the sap of the sugar maple tree. When It is inside the tree, the sap is sterile. The sap moves through the plastic pipes and into the holding tanks. The piping and holding tanks are sanitized after every sugaring season to avoid contamination.

The sap is then boiled until It thickens from a previously watery to a syrupy consistency. During the process, the water evaporates leaving behind the thick and sweet maple syrup.

During heating, maple syrup has to reach a safe temperature of 219℉. Then It is allowed to rest in the holding tanks. Then it is filtered. Before bottling, the syrup is again heated to a minimum temperature of 180 degrees to sanitize the bottle as the syrup is being poured.


In this article, we answered the question “Does syrup go bad?”, and how to tell If Maple syrup is bad?


Hello, I'm Sana Ameer. I'm a student of Food Science and Technology at UVAS. I like to bake and I aspire to become a Food blogger.