Moldy maple syrup - safe to eat? And cook down so it won't mold again?

I don't use maple syrup very often, and have two open bottles of it that have mold on the surface.  I've read on the internet that it's safe to skim the mold off and eat the syrup.  In my case there are two kinds of mold, one has a thin white mold right on the surface of the syrup.  The other has what looks like a light brown yeast on the surface - it looks like bread yeast actually.

I don't have a fridge so there's no way to keep this from happening other than eating the syrup quickly after opening.

I have two questions:

1.  Anyone agree or disagree on the safety of eating moldy maple syrup?  (after skimming the mold.)  I won't sue.

2.  Has anyone cooked their syrup down to a lower moisture content so that it won't spoil?  i.e. a thick syrup in between maple sugar and syrup?  I don't see why this wouldn't work, I suppose the reason syrup is sold with so much water is tradition, so it is thin enough to pour, and perhaps originally to save on the effort of cooking it down.

When I left the US I brought a half gallon of maple syrup with me, in hopes that it would do for a while. It went moldy in the fridge over a few months.... green mold, it smelled, and it still hurts to think about how I had to pour it down the drain!! (last year I bought another jug, and so far it's still good, living in my fridge. No longer having children who swig from the jug may have helped it stay this time....)

that said, I am cool with paring mold off my fancy cheese and eating it. I think the appearance and smell of your mold may lead you to decide what to do with it. I do think concentrating it will help it last longer- here we do that with sugar cane juice to make molasses, and if you boil it enough it becomes sugar (piloncillo, rapadura, jaggery). If it's still liquid to some extent it will eventually ferment (I've had molasses decide it wants to become rum in my closet). I think if it were me and I had a non-nasty-smelling mold I could scrape off I would consider boiling down what is left. As always, use your best judgment!

if it’s real maple syrup and it was stopped at the right time (66.9% sugar), any further and you start getting crystallization (and if you keep adding heat once you’ve got crystals you start running the risk of caramelization/scorching)…maybe a dehydrator or another lower-heat option?

Ours did this. My mother cooked to kill the mold, then refrigerated it again.

Honestly, though no one has died or gotten ill, IMO it tastes bad and I don't use it much. So it's lingering in the fridge.  My mother claims it tastes fine.

 It hasn't molded again, making me wonder if the original makers (it's home made) didn't sterilize the jars, or didn't reduce it to the correct sugar content.

I don't see why it COULDN'T be canned in some way, but have no experience to back this up.

As much as I hate waste, if your gut instinct (based on weird smell, off taste, appearance) tells you it's dodgy, chuck it out. Don't worry, the trees will be pumping fresh sap very soon.

I've rolled/gathered the mold scum off the top before and used the syrup.
It kind of stuck together in a lump.

Further thinking about canning - since maple syrup was traditionally a storage product.

I found an interesting suggested method. They recommend freezing, first, as the recommended method of storage. They warn canning isn't technically approved, but give suggestions for how to imitate the commercial process, which occurs at 85C. They warn heat can darken the maple syrup, changing it to a lower grade (I love darker maple syrup, so this didn't bug me).

See here:

https://www.healthycanning.com/maple-syrup-canning-or-freezing

I wonder if one could take those little 125mL canning jars/jam jars, and make individual maple syrup serving containers. Sterilize well, repack, heat treat for 5 min, etc... all the suggested steps in the article, which would get you about as good of a seal as the storebought stuff.

Anyway - possibly an option for future maple syrup purchases.

I grew up scooping white mold off preserve and then enjoying the preserves.

If the mold can be successfully scooped off and the syrup smells good, then I would enjoy it.

I hate throwing away food but I am miles from the nearest medical facility so I don't want to take a chance on food poisoning.  Anything questionable gets thrown out.

Someone mentioned dehydrating the maple syrup.  I really like this idea so if I didn't have refrigeration or freezing available that is what I would do.

Another option would be canning the maple syrup into smaller container so it would be used up before it molds.

I've had properly boiled down syrup mold in the fridge after a very long time (my syrup in someone else's house).  We drink it too fast to have that happen around here.

Outside a refrigerator, once opened, the mold is destined to occur eventually.  I'm not really sure I'd eat it.  I've heard it's fine but I've heard a lot of things are fine that I don't think are really fine.

Boiling it down further should make it more shelf stable.  It's just tricky to do so without ending up with some weird crystal science experiment.  If you're lucky and the "invert sugar" level is in the correct range, you can turn syrup into granulated brown sugar.  It's not easy but it's doable.  And then if you want to turn it back to syrup you can just add the right amount of water.  The issue is that if the invert sugar level is not correct, you'll make a hard caramel or other sugary lump instead of nice sugar.

My sister makes syrup for the family. One year, a batch went moldy - she hadn’t canned it. We skimmed the mold off, tasted each jar for off flavors, brought it all to a boil, and waterbath canned it
It was the best I have ever eaten. It came out of the jar the consistency of dark honey. Ince the jar was opened and dipped into, it crystallized, kind of like honey does. A bit harder to scoop out, but melts into pancakes just fine. She used some of the crystalized stuff to make ice cream.
Not telling anyone else to skim the mold, but nobody in our family died…

We have been making our own maple syrup for the past 8 years. Over that time I would say a few jars each year get a white or yellow scum mold. How ever it just covers the top of the jar but does not really grow much, even over the year it takes us to eat the syrup.

We do not can the syrup or anything. We just boil it down and when still hot do the final strain and into jars that have a canning lid. Syrup done like this and kept in the pantry has kept for 2 years before we ate it.

I don't know about moldy, but I can speak to canning the syrup.  We started making syrup maybe 15 years ago.  We figured the best way to keep it, since one year we got 36 pints of syrup from two massive silver maples, was to can it.  We "sterilized" jars by pouring boiling water over clean jars and the seals, and just poured the boiling hot syrup into the jars as soon as we determined it was done, closed up the jars, and left them on the counter to cool.  None of the jars grew mold until after they were opened, and some of them stayed in the pantry, unrefrigerated, for a decade.

It occurs to me that, I think this is the first time I've actually posted on here, despite lurking around for years, so, cheers!

I sure ain't no expert on maple surple, nor physics but my intuition says mold is light, hence it forms on the top and I'll venture, NOT GUARANTEE, that mold can't mix downward without agitation. But remember, I was wrong once in my life so take this under advisement.

I'm not sure why would one need take this past the temperature that kills mold, okay some few extra degrees [but not necessarily to boiling point]  to be on the safe side?

And there is the argument, elucidated here at least once, that it just ain't worth food poisoning. I know that animals and I think that some people can simply upchuck and be okay whereas other people [or just the particular situation] do get food poisoning, which when you think about it, is a misnomer.

Yes you can safely skim or pour a jar of maple syrup through a strainer to get mold out of a jar. The next step is to heat the syrup to boiling to kill any remaining mold. If syrup is made from spoiled sap the syrup will have a sour smell and taste that won't go away if you boil it. The sap can sour at the end of the season if the temperature outside is very warm. When this happens the sap will thicken, get milky looking and smell and taste sour. If any of this sour sap is added in to a batch it will ruin the flavor.
 Also if you reboil a jar of syrup after removing mold one way to keep it from getting too thick is to add some water before boiling. Otherwise if you boil it you may turn it into maple cream which is a thick spread next maple candy which is sometimes molded and next step is maple sugar. To turn syrup into any of these alternate forms you must keep stirring and be careful not to have the heat too high as it can burn. But in those other forms it won't mold and can be turned back into syrup by adding water. But the other forms are as useful as is maple syrup. Traditionally they have all been made and continue to be made to this day. I have made syrup for my own use for about 40 years so I have a bit of experience with sharing on a small scale.