Our organic grade A maple syrup, bought in bulk, has gone slightly fermented in the fridge. If I were still in college, this would be great, but I am a bit older. What do I do with this stuff? Can I assume it is fine in baked goods? How can I accelerate my usage of it?

  • 2
    Mmm, Dendarii Mountain Maple Mead...
    – Marti
    Commented Dec 20, 2010 at 18:06
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    can you describe the fermented syrup? How does it smell / taste / look? Commented Dec 21, 2010 at 5:56
  • just like regular maple syrup, but a little bit like wine. We keep it in an airtight bottle with one of those ceramic stoppers. When we open the bottle, there is some pressure released: it pops. So I believe there is some fermentation going on. This is in the fridge, so it cannot be going wild.
    – shabbychef
    Commented Dec 23, 2010 at 1:17
  • "airtight" bottles and gas production indicate anaerobic bacteria, which are not Good Eats. Of course, "airtight" may not actually exclude much oxygen, particularly if you open the bottle frequently.
    – kdgregory
    Commented Apr 12, 2011 at 13:16
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    /@kdgregory: the point behind airtight storage of syrup makes sense when it is bottled: namely finished syrup is at 219 F at sea level, so the hot syrup helps to keep the bottle sterile. (w/ home bottling you're supposed to put the bottle on its side for a few minutes after sealing so that the top of the bottle gets heated up) After it's been opened, the bacteria can get a start, if the sugar content is low enough. If you buy in bulk (are you talking 1 gallon qtys?), I'd seriously consider rebottling in smaller canning jars: minimize the amount of syrup you have "open" at a time. Commented Apr 12, 2011 at 23:43

5 Answers 5


Yeah, syrup can ferment + convert sugar to alcohol. It has more of a tendency to do so if the sugar content is lower -- I tend to err on the side of overconcentrating my syrup.

You can try boiling it for a while to see if the alcohol boils off + if the flavor is OK then use it... but I'd boil down a bit more first, to make sure the sugar content is back up to standards. Either boil until the boiling point is 7 degrees F higher than the boiling point of water at your altitude, or boil until the syrup "aprons" (e.g. starts to drip in a sheet rather than discrete drops; a flat edge of a metal spatula works well), with the former being more accurate if you have a good thermometer.

If the flavor remains after boiling, then try using in recipes -- perhaps in brownies/blondies or with ice cream.

  • +1 for the idea to reboil. Based on what I learned while helping a friend with his annual boil, it sounds like the producer did not take the syrup to the correct gravity.
    – kdgregory
    Commented Apr 12, 2011 at 13:18

That sounds like it would work well for glazing pork or maybe smoked chicken/turkey.


There is just one thing I can think of. Maple Sugar Candy :-) The alcohol ferment will cook off some and leave behind the sugar.


It is hard to correctly answer your question, without knowing all the facts. Was/Is this Canadian Maple Syrup? Vermont Maple Syrup? Or Maple syrup from another part of the US? Vermont's regulations for the production & labelling of Maple syrup, are similar to those you find in Canada. Canada has some of the most stringent laws concerning the collection, processing, bottled and labelling for Maple Syrup in the world. If your Maple Syrup is from Vermont or Canada, I would throw it away, as it has become contaminated with something that most definitely would be toxic if consumed, and no amount of boiling it will help, it would actually concentrate the toxin even more. If your Maple Syrup is from another part of the US, (or another country all together) then you might not have 100% maple syrup &/or the concentration of the maple syrup could lean itself to fermentation, which would make a lovely mead like liqueur. In Canada they actually use Maple syrup to make liqueurs, wine, etc. However to do this they have to adjust the maple syrups sugar concentration to allow for the fermentation to take place. I would say better to be safe then sorry, and ditch it. If you do in the future decide to buy the larger container & try re-bottling it, be careful that you get your bottles extremely hot & boil the maple syrup to get it extremely hot as well, prior to pouring the maple syrup into the jars to seal. Good luck!

  • Hello, and welcome to Stack Exchange. This doesn't make much sense; you say the Vermont and Canadian standards are the most stringent, but only keep the syrup if it's not from them? Commented Jan 23, 2017 at 3:46
  • I believe the implication is that because it is made to such stringent standards, regular alcoholic fermentation should not be possible due to the low water activity. If it's not from those places, it might be sloppiness in production, and therefore it might be alcoholic fermentation and A-OK. I'd like to know what other kinds of fermentation can occur in maple syrup though.
    – J K
    Commented Jan 23, 2017 at 9:46

I think there is WAY too little water and oxygen in maple syrup for a yeast fermentation, so anything that grew in this syrup is probably bacteria or worse. Don't drink it.

  • There is evidence of there being alcohol. Based on that, the OP could research whether there is anything that could have happened that left toxins in there while alcohol was produced. Commented Nov 8, 2016 at 10:09

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