I opened Adirondack pure maple syrup a few days ago. It didn't say to refrigerate, so I didn't. When I googled it, it said that it should be refrigerated. Can I still do that? If I may not use it for a while, should I freeze it?

2 Answers 2


Unless you left it open to the air it should be perfectly safe. Maple sap is thickened into syrup via boiling so any bacteria/etc. originating in it will be killed off.

Thick sugary syrups also make it very hard for bacteria and mold to grow. Despite the plentiful food source, the concentrated sugar is dessicative:

OK, maple syrup is wet, but it’s also extremely high in sugar. All that sugar has the effect of pulling water out of cells, and the vast majority of fungi can’t grow in maple syrup at all [...] maple syrup typically has a water activity of about 0.87 to 0.88, pretty hostile to most molds.

Syrup doesn't have the other nice properties honey that make it virtually immune to nasties, though, so I wouldn't continue to leave it out. If you are particularly concerned you can always boil it.

For anyone else wondering about "fake" table syrup:

fake maple syrup resists molds through the miracle of chemical preservatives (usually sodium benzoate and sorbic acid)

  • In Canada I heard they put that stuff on everything.
    – Chef_Code
    Apr 13, 2015 at 7:49
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    Speaking from experience, opened bottles of maple syrup will sometimes develop a little mold at the top after being kept at room temp for weeks. However, that mold can be skimmed off and the rest of the syrup is still safe to eat.
    – FuzzyChef
    Apr 14, 2015 at 4:42

Will be perfectly fine.

Maple syrup does not have enough sugar to prevent mold and no preservatives, so like bread or wine, it can develop mold after 7 days or so, pending the environment.

1 or 2 days, not an issue.

Typically it's what you add to syrup that causes the mold after opening.

Plastic containers shorten shelf life Conisderably to about 1 month, glass and tin can do 1 year in your cupboard as long as no organic material is ever introduced into the container.

  • Maple syrup tends to be about 2/3rds sugar, is that not enough? The sources I've see (one linked in my answer) say that the sugar does inhibit mold. Apr 12, 2015 at 20:35
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    I've made it a couple times when. I had maple tree's; Was possible to get mold on top surface if you didn't sterlize your containers. Good be some minor separation that allows it to grow on top. Old school Maple syrup guys would just skim the mold off, I throw out the batch.
    – zerobane
    Apr 12, 2015 at 20:38
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    @MatthewRead I've seen maple syrup go mouldy after being left in the fridge for a long time.
    – Ross Ridge
    Apr 12, 2015 at 20:55
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    I'm not questioning whether mold is possible. As far as liquids go maple syrup is quite good at hindering the growth of mold thanks to its sugar content so it seems quite odd to single it out as not having enough to make it impossible -- that's just a truism you could say about almost anything that isn't pure sugar kept perfectly dry. Apr 12, 2015 at 21:04
  • think the point is most maple companies will say to keep refrigerated to inhibit mold or bacteria growth. Does not stop, but will signicantly delay.
    – zerobane
    Apr 13, 2015 at 2:42

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