Once opened, maple syrup will eventually begin to form mold on the surface. At average room temperature this may take anywhere from several days to a few weeks. I normally figure a couple weeks before any is observed. Refrigeration is recommended to insure that molding does not occur. If syrup does mold, remove as much as possible and carefully boil for several minutes. Use extreme caution because the syrup can easily boil over.

I have kept syrup that has been opened for over a year refrigerated. The container should be kept closed to avoid absorbing other flavors. It can also be placed in the freezer which will provably keep it as long as the freezer lasts. It's said that some of the flavor may be lost when unopened syrup is kept for several years. During the 90's most of our sugar bush was destroyed by a sheer wind, and we had to resort to using up our supply for the next 6 years. Maybe we just have bad taste buds, but none of us could detect any change.

Here by thick or thin we are actually referring to the viscosity of the syrup. First, it should probably be noted that most Maple Syrup will not be as viscous as commercial brands that may contain some form of corn syrup. So, don't expect pure Maple to have that type of thickness (or viscosity). There are a couple reasons why I believe individual syrups will differ in viscosity. Syrups made later in the season are usually darker in color, contains more glucose than earlier in the season, and seem to have higher viscosity. A second reason they can differ is the percent of sugar in the syrup. For Maple Syrup to be considered as legitimate, it needs to be 66% sugar. More than this percent will increase the viscosity. This happens by removing more water from the syrup during the normal boiling process. There is a noticeable difference by just a few percentage points. Many producers shoot for the 66 or 67 percent to maximize their production and profits. Producers can expect a 3-5 percent decrease in production by going from say 66 to 69 percent. Besides from losing profit, when syrup is at say 69-70 percent, it has a tendency to form crystals of pure sugar in the container, especially when refrigerated. Instead of a problem, it's actually a sign that the syrup contains less water and more sugar, which is what the customers are paying for. It will also tend to stay (on top) of the pancake or French toast, rather than sinking into it.

Short answer is no. Maple Syrups that are identical in color will not necessarily taste the same. They can of course it they were made or bottled from the same batch of syrup. Flavor of Maple Syrup is complex, and can vary depending on many factors, one being the location of the Sugar Bush it comes from. Even Syrup coming from that same bush can vary slightly from year to year, so that say Dark (or Medium) grade can taste slightly different. In that way, Maple Syrup is more like the production of wine, and many other agricultural products. I compare it to getting oranges. Sometimes they are super, and sometimes not quite; but good, nevertheless.

Some producers chose to have their syrup certified as organic. The idea I believe is that it will increase sales or encourage the sale of their products. It can also give the consumer an added feeling of protection. There is usually a fee for this that is paid to whoever, or whatever has the authority to grant this title. The producer also will be inspected by the entity before being certified. Some of the things that are most often checked for are location of the sugar bush, what (if anything) is added during the processing, and chemicals used (if any) during cleaning of equipment. For more details, customers can check online. Most (if not all) of these things have been checked by State Inspection before the producer is given a license to sell to the public.

My opinion is that most, if not all, of the produces that have passed State Inspections would quite easily be able to be certified as organic. I believe many producers hold that this is an unnecessary addon, designed to satisfy those customers that desire this guarantee, and are willing to pay extra because the producer will probably need to pass on the additional cost.