After opening, all maple syrup should be stored in the refrigerator. If your syrup is properly sealed and has not been opened, you can store it indefinitely at room temperature.
Do not despair. For generations, syrup has been restored to a consumable state by probably tens of thousands or even hundreds of thousands of people using the following steps.
Maple syrup typically hosts a wallemia mold. “Wallemia is a distinctly weird mold. It’s so weird, and so distantly related to most other molds, the authors erected a whole new class of fungi just for it, class Wallemiomycetes. Within this entire class there are only three species, Wallemia sebi, W. muriae, and W. ichthyophaga. Just for reference, you and I and my dog and almost every furry creature in the world are Mammals–that’s a class too.”1 For a thorough discussion of Wallemia mold, a bunch of interesting personal stories and contributions to science through individual experimentation with consumption of syrup mold and a constant reminder from the mold expert that you should not consume maple syrup check out this site:
Serious mold science/No testing done on animals; testing done on self!
If your syrup appears stringy or has a foul odor in addition to the mold, it probably was not produced correctly and the mold is not the only issue here. The mold is not the issue. Something else is amiss and you should probably toss the mess out. If the mold is a light greyish color and seems powdery on the surface, this is the typical maple syrup mold (wallemia) that has traditionally been removed as follows:
1. Gently skim off as much mold as reasonably possible off the top of the syrup. You don’t need to nor, in case of agitation, may it be possible to get all the mold out of your syrup.
2. Put your syrup in a stove-top ready container and bring it to a boil for less than a minute. Boiling for too long will eventually change the consistency of the syrup.
3. If you want to return the syrup to the original container, wash (then rinse) this container thoroughly with soap. Otherwise chose a clean container and pour the hot syrup into it.
4. Put the syrup into the fridge
Side note, sometimes in the case of long term transportation or shaking, bubbles may form in the syrup that take a considerable time to break down and may appear to be a mold or some confusing surface layer on your syrup. If such transport has happened, put the syrup in the fridge for a spell, say 24 hours and reassess at that point.
Single source maple syrup is simply that: Maple Syrup that comes from one farm and has not been blended with syrup from multiple producers. This is how all the big distributors do it in order to maximize volumes of certain grades as well as their resulting profits. If you ever see a label that mentions “syrup from the U.S. and Canada” or some similar all encompassing phrase beware as the flavor will likely be more bland and compromised.
Having helped my parents sugar (the local verb used to describe the act of making syrup) for my entire life has taught me a lot about the subtleties of producing and recognizing quality maple syrup. As an independent contractor conducting inspections for Vermont Organic Farmers, the primary organic certifier in the state, I have had the opportunity to view many different production and processing methods.
I can only guess an answer to this question. Perhaps my large diameter, reusable glass packaging allows for a greater volume of syrup to be moved around and viewed so that the true nature of the syrup – distinctly liquid at room temperatures- is more visible.
All pure maple syrup is essentially the same density. 11 lbs/gallon (Water is 8 lb./gallon, whole milk 8.6, honey 13) Pure Vermont maple syrup is 66.9% sugar some other locales deem syrup finished at 66% sugar. When the syrup is removed from the heat source the density is tested using a hydrometer. This is very important as syrup that is too dense will eventually crystallize at the bottom of the container and syrup that is too light will ferment.
We boil our syrup over a raging fire of well-dried hardwood, not nozzles of oil or gas. We run our reverse osmosis machine at 7% sugar, not 10%, 15%, or even higher as some producers do.
Reverse osmosis is simply a process that filters water out of the sap. Maple sap usually ranges between 1 and 3 percent sugar. A reverse osmosis machine can increase the sugar content to over 20 percent. A sugar molecule (C6 H12 O6) is much larger than a water (H2O) molecule. Water is filtered out by placing the sap under pressure against a very fine membrane that only allows water to pass through. The remaining water in this concentrate can then be evaporated to produce syrup much faster. Finished Vermont maple syrup is a minimum 66.9 percent sugar.
Most importantly, be assertive both in starting to pour and stopping the pour. Secondly, find the place where the raised glass thread at the top of the jar comes closest to the opening of the jar. Pour so that the syrup exits the jar right at this point minimizing the amount that can run down the side of the jar before it is forced to drip out away from the jar. I hope you are surprised at the effectiveness of these methods.
Periodically rinse the entire lid/ring combo and put it back on the jar. If the stickiness is mostly on the jar itself, you can easily transfer the syrup to a new container. Don’t forget to let your original container sit on the counter to come to room temperature and pour those last few drops into your new container. This step can be repeated if necessary. I recommend pouring the last few drops directly into your mouth!
Tighten the lid on your jar and while holding it upright run it under some warm water. Attempt to tighten the ring and lid a bit more. Run under water again. If you feel your lid won’t leak, turn the jar sideways while running it under the warm water rotating the container so that the water can penetrate under the lip of the ring that holds the lid in place.
Finally if you really want a clean ring and lid, remove them from the jar, rinse well under warm water, shake off excess water, replace on jar, and put the container back in the fridge.
Don’t worry, this happens. Simply hold the jar slightly off the vertical axis and rotate running it briefly under some warm water. Try to loosen. If still stuck run under water for a bit longer. Savor the sweetness after opening!
Vermont maple syrup is graded on both flavor and color. There is an annual grading kit with sample jars full of solution to define each grade by color; FANCY, GRADE A MEDIUM AMBER, GRADE A DARK AMBER, and GRADE B. We fill a sample jar with syrup and compare its color to those in the kit. Additionally syrup may be graded COMMERCIAL based on extra dark or off flavor characteristics.
In general the lighter syrup grades have a lighter flavor. As such, which ever grade tastes best for your particular palate or application is the best grade for you! A wise man once said, “If you’re going to bring one, bring two.”