UVM Proctor Page


Off-flavor syrup reference available

Kit intended for anyone who works with pure maple syrup


A new product to help producers identify off-flavors in maple syrup is available for the 2017 production season.  

The product, officially known as the Off-flavor syrup reference set, was developed by the University of Vermont Extension Maple Program.  The kits are intended for anyone who works with pure maple syrup, especially those who are responsible for grading pure syrup and are using flavor terminology common to U.S. producers.  

The Canadian based Centre Acer, developed the first kit of this kind and utilizes flavor terminology common to Canadian producers.  Both sets share the same goal, to serve as a reference for producers and help prevent off-flavored syrup from reaching the consumer.   

The Off-flavor syrup reference set includes three, 1.7oz bottles of naturally off-flavored maple syrup.  Given that off-flavors can occur along a range of intensities the samples in this kit were chosen to represent a ‘middle of the road’ example of each off-flavor and not the most extreme.  The ‘Mother nature off-flavor’ set includes the three most common off-flavors that occur as a result of the tree or environment; Metabolism, Buddy and Sour Sap.  Metabolism off-flavor does not show up every season or at a particular time during the season.  Some have observed this flavor appears and disappears following rapid shifts in temperature.  This off-flavor has been described as woody, popcorn or cardboard.   Buddy off-flavor is almost always produced as the very end of the season.  Although not definitively tied to a particular stage of spring bud development, it is commonly understood to be related to the trees exit from dormancy.  Buddy syrup is often described as having a chocolate or Tootsie Roll flavor. The third off-flavor is Sour Sap. This off-flavor is the result of sap being held too long in temperatures (typically found at the end of the season) that are warm enough to promote growth and development of microorganisms.  Syrup made with this sap can have a slightly ropy appearance or texture and possess a sour taste.  The syrup in the bottles have been carefully selected in cooperation with a large packer of maple syrup, officials with Vermont Agency of Agriculture, Food and Markets and UVM Extension.  

Another benefit of these sets is to help develop some level of consistent knowledge within sugaring operations around the issue of off-flavored syrup.  Sometimes those operating evaporators can become so saturated with the smells of the sugarhouse that when off-flavors begin to develop it can be challenging to detect.  Also not everyone has the same level of experience tasting maple syrup and in fact not everyone has the same concentration of taste buds.  This can lead to confusion when it comes to flavor grading syrup.  By having everyone in a particular operation taste the same samples in the same conditions and discuss a given sample at the same time inconsistencies in flavor grading syrup may be avoided.  

The samples must be refrigerated or frozen after opening to ensure the syrup doesn’t spoil or otherwise loose its particular flavor characteristics.  

In addition to the syrup samples and small tasting spoons, the set also includes a reprint of ‘The Maple of Maple:  Off-flavors’.  This document represents several years of collaboration between UVM Nutrition and Food Sciences, Vermont Agency of Agriculture, Food and Markets and maple producers.  It includes carefully selected language to help define the most common off-flavors that sometimes arise in the production of maple syrup.  The document is printed on special ‘waterproof’ (Rite-in-Rain) paper, suitable for moist sugarhouse conditions.   

“Flavor is what sets maple apart from all other sweeteners.  Occasionally, undesirable flavors are present in finished maple syrup.  Syrup flavor can be impacted both before and after the syrup has been produced.  Sometimes there are more than one off-flavor present.  It is the producers job to recognize if any off-flavors are present and prevent off-flavored syrup reaching a retail container.” 

— Excerpt from off-flavor set insert   



Off-flavor syrup reference set

The kit can be purchased through the Vermont Maple Sugar Makers Association.  

The cost is $10, plus shipping and handling.  

Contact Amanda Voyer at for ordering.