Is maple syrup mold harmful?

Asked March 10, 2019, 2:04 PM EDT

I’ve heard that the mold that sometimes grows on the surface of maple syrup isn’t harmful, and that one can simply pour the syrup through a coffee filter to remove it. Other people say that you should throw out the syrup and buy a fresh bottle. Which is right, and if filtering works are there any other steps one should take to slow the reappearance of mold? Would heating the syrup to a certain temperature help? Should we store our syrup in the refrigerator?

Baltimore County Maryland

1 Response

Thanks for your question. University of Vermont Extension Maple Specialist Mark Isselhardt writes:

Throw out the syrup. Open syrup should be refrigerated or frozen until used. The recommendations used to be to reheat and skim but we don’t say that anymore; there are just too many potential problems that reboiling and filtering just can’t fix. If the syrup was moldy when they first opened it they should contact the producer and get a replacement (this also helps the producer identify that something in their canning procedures might need to be changed). If the mold formed after they opened it, it’s probably due to not storing it in the fridge or freezer. BTW syrup won’t freeze solid given its high sugar content. We recommend freezing syrup in glass to maintain the flavor of larger quantities.

Hope this helps. Don't hesitate to reach out with any other questions.