Sap & Syrup

  •  Deirdre Schirmer of Treehugger Maple in Laurel, Ind. inspects one of her hydrometers at the Indiana Maple Syrup Association annual meeting in Greencastle, Ind. on Dec. 3, as IMSA Vice President Vince Milnes looks on.

  •  Marc Paquette, chief metrologist for the Vermont agriculture agency, says the failure rate of new hydrometers has doubled over the past three years.

  •  A big batch of hydrometers direct for the maple equipment companies are stacked, waiting to be tested at the Vermont Agency of Agriculture weights and measures testing lab in Randolph, Vt. on Dec. 10.

Many syrup hydrometers out of whack, officials say

Sugarmakers are encouraged to get hydrometers tested


RANDOLPH, Vt.—Producers and state officials are checking syrup hydrometers and finding they’re off.
At the state laboratory in Randolph, Vt., weights and measures officials for the Vermont agriculture department so far this year tossed out 6.6 percent of the 11,4126 hydrometers checked. A total of 749 hydrometers were rejected for sale.
“The failure rate has doubled since 2019,” said Marc Paquette, chief metrologist for the Vermont agriculture agency, who oversees the lab testing.
Vermont is the only state in the nation that offers official testing of hydrometers, and all of the big equipment manufacturers send huge batches of hydrometers to be tested there before they are sold back to sugarmakers.
Before the year is over, Paquette and his team in the official Hydrometer Volumetric Room at the state office campus in Randolph are expected to test and verify upwards of 15,000 hydrometers, a record.
Hydrometer checking was also a highlight at the Indiana Maple Syrup Association annual meeting in Greencastle, Ind. last month.
There, Mary Fogle Douglass of Sugar Bush Supplies brought in an official hydrometer testing kit where a weighted test hydrometer is floated in a solution of potassium iodide and compared against the sugarmaker’s hydrometer. 
Sugarmakers at the Indiana show brought their hydrometers from the field and found many were out of calibration. 
An “off” hydrometer means that the sugarmaker is making syrup that is either too thin or too thick and will lose money on their syrup either way.
Douglass told sugarmakers that the most common way hydrometers go bad is the paper inside can slip out of position. Other times the glass can break, most often by the sugarmaker “dropping” the hydrometer too hard in the testing cup.
Douglass suggested that sugarmakers keep their hydrometers clean during a boil, rinsing them often with distilled water, permeate or vingegar to make sure sugar sand doesn’t build up on them and weigh them down.
“You want it to be a nice clear glass,” she told the Indiana audience.
Douglass said she likes hydrometers to have more markings on the paper.
Hydrometers are sold in different lengths and the longer ones are recommended since they have more detailed and precise marks on the paper.
“The more marks, the more accurate you will be,” she said.
Overall, hydrometers are very reliable, she said.
“Hydrometers for their costs are very accurate and can last for decades,” she said. “It’s the go-to way to check your density.”
Most maple states have hydrometer testing services, a lot of times through state maple associations. 
When buying a new hydrometer, it is recommended to buy one that has been officially tested in the Vermont lab. 
Those hydrometers are marked as such with an official stamp from the Vermont agency of agriculture.