Every once and awhile it is good to go back and revisit an old post with a good message – here is one from 2013 with a few additions.
Maple syrup is often referred to as “liquid gold.” Increased demand for maple syrup and the escalating value of this year’s crop has added new meaning to this term of endearment. Once the season is over, you need to use a little TLC when it comes to storing maple syrup so it will maintain its quality and value. If you have not sold all of this year’s maple syrup and have some left in the sugarhouse, you need to pay careful attention to the inside temperatures of those buildings. With all of the recent hot weather, syrup stored in non-insulated structures can quickly reach high temperatures and spoilage can occur. You may think you safeguarded your product by packing the syrup hot in a sealed container. Maybe not!
Most syrup is stored in stainless steel barrels that were packed in February and March. Syrup should go into barrels hot and sealed with as little air as possible. The drums then cool to the ambient temperature with the syrup soon reaching the same temperature inside. Steel as a general fact transfers heat and cold well. The syrup on the inside of a steel barrel will remain cold for a long period of time due to its viscosity and mass. However, this also means that if the steel on the drum’s exterior warms quickly to 80 degrees Fahrenheit or above and stays warm, the result is condensation that will develop between the warm steel and the cool syrup on the inside. If this moisture develops in the interior air space, molds can form. This is the same thing that happens to jugs when they are not heated properly to 185 degrees. If the product is not above 66 Brix, syrup can even ferment. The worst culprit for spoiled syrup is a partially-filled drum that is then topped off with hot syrup. This scenario can be avoided by repacking the entire drum between 150 and 180 degrees Fahrenheit. It is always best to completely fill a drum with hot syrup right off the filter press, seal it, and store it.
The best solution for long term storage is to build a cool room. You notice I did said cool, not cold. A walk in cooler would be the best case scenario but most producers cannot afford such a luxury. Take a small space big enough to hold several drums of syrup. This could be a closet or small room in a building. Insulate the room and stick a window air conditioning unit through the wall. When temperature exceeds 80 degrees Fahrenheit for any length of time, kick on the air conditioner and cool the room to just below 70 degrees. At that temperature, the syrup will stay relatively cool in the barrels. Your biggest struggle is to get the syrup through the hottest months of the year. Another trick is to rotate the drum occasionally, this moves the syrup inside the drum and should dissipate any moisture that forms on the interior metal wall of the drum within the residual air space, thus reducing the chance of spoilage if the drum was packed correctly to begin with.