•  Color grading was the biggest problem, as part of a quality study by the University of Vermont. (Mark Isselhardt)

  •  Nearly one in four samples of dark robust were off flavor, according to a study of syrup bought online, conducted by the University of Vermont Extension Service.

  •  UVM Ext. researchers bought syrup samples online and found many quality issues, especially in color grading and off-flavor. (Mark Isselhardt)

Many quality defects found in online syrup, say researchers

UVM Ext. study found zero of golden samples met grade


MORRISVILLE, Vt.—Many quality defects were found in syrup bought online, Vermont researchers found.

Nearly in one in four samples of dark syrup bought online was off-flavor, according to a study conducted by University of Vermont Extension.

“Everything flows from quality,” said Mark Isselhardt, maple specialist with UVM Extension who conducted the study with colleague Mark Cannella, also of UVM Extension.  “You can’t expect consumers to pay a premium and not give them what they are expecting.” 

Isselhardt and Cannella bought syrup samples off the internet from various maple states including Vermont, New York, Maine, Ohio and Massachusetts and tested for clarity, density, color and off-flavor. 

There were a total of 116 samples of Golden Delicate and 129 samples of Dark Robust.  Three samples each were ordered from each producer. 

A striking result was that zero of the samples that were graded as Golden Delicate met the standard for color, Isselhardt said.  The syrup was instead graded either as Amber Rich or even Dark Robust.

“The number one issue was color,” Isselhardt said during a presentation for the International Maple Syrup Institute last week.

Other big stand-out problems came from the testing for density, which can be tricky for some sugarmakers. 

Of the samples, Golden Delicate was the biggest problem, with 38 percent of the samples testing below the density standard for the state of Vermont, which is 36 degrees Baume or 66.9 degrees Brix at 60 degrees Fahrenheit.

For the dark samples, 18 percent were below density for the Vermont standard, Isselhardt said.

Isselhardt and Cannella also found many of the samples were off-flavor, running a gamut of problems.

“We had samples that had mold. Buddy. Metabolism. Fermentation. A little bit of sour. Clarity defects were the result of mold which caused that defect,” Isselhardt said.

Of the off-flavor samples, it was the darker grades that had the most problems.

“Five times as much of dark was off flavor compared to the golden,” Isselhardt said.

Isselhardt and Cannella will present a detailed report on their findings later this year.

Meanwhile, the Vermont agency of agriculture is aggressively inspecting maple at retail.  

Between January and May of 2021 the agency reported there were 411 maple syrup products inspected, all bought in retail settings.

Fifteen citations were issued. A similar inspection campaign is expected this year.

The agency reported the following trends in their inspections:

  • Color darkening in plastic containers was the #1 issue

  • Missing batch codes was reported as the #2 issue

  • Mislabeling was the #3 issue, including inappropriate use of the term “Vermont maple”

  • Moldy syrup was #4.