by Elizabeth A. Tomlin
“Has your syrup ever been disqualified?” asked Les Ober, CCA, maple syrup production specialist at Ohio State University Extension.
Ober was speaking to a standing room-only crowd during one of his presentations at the 2019 NYS Maple Conference/Mid-Winter Maple Classic, where numerous educational sessions ran concurrently at the NYS Fairgrounds in Syracuse, NY.
Ober said grading maple syrup continues to be a challenge for many maple producers. Being able to identify a quality product for density, clarity, color and flavor is paramount for maple syrup producers.
“Flavor is the defining thing,” said Ober. “If we don’t have good flavor, customers don’t come back.”
Each of the four classifications of syrup has a unique flavor and Ober explained that flavor varies from one geographical location to another based on minerals in the soil. This concept is known as “regional flavors.”
By law, three ingredients are allowed in packaged maple syrup: salt, a chemical preservative and a defoaming agent. “The addition of any other additive is adulteration,” he said.
Density is where Ober said people constantly make mistakes. By law, maple syrup cannot be less than 66 brix. Mold can occur when density is not correct.
“Density affects syrup quality in several ways,” Ober explained. “First, syrup must be 66 brix to meet USDA standards and if it is below 66 brix it can ferment and cause an off-flavor. Syrup above 67 brix normally does not have an off-flavor, but the higher density can cause crystallization in the bottom of the container and loss of revenue to the producer.”
Density and color will change rapidly with the removal of water and increase of sugar concentration.
Ober said improper density management may lead to two off-flavors common in syrup: fermented and scorched.
Three tools are used to determine density: a hydrometer, a thermometer and a refractometer. These tools must be maintained and kept clean to assure accuracy.
“Hydrometers should be inspected or checked for possible problems and replaced if suspect. Often the paper with the scale printed on it can slip, resulting in the wrong brix reading. The hydrometer can become coated with film resulting in an inaccurate reading. A good hydrometer will give you an accurate reading only if it is used at the right temperature,” Ober said. “Temperatures below that require consulting a chart to get the right brix reading for a specific temperature. Maple syrup boils at seven degrees above the boiling point of water, or 219 degrees. Many producers use a thermometer to determine the draw off point. The only problem is that that the 219 reading is only accurate if the barometer is at 29.9 hg barometric pressure. A thermometer needs to be recalibrated every time the barometric pressure rises or falls.”
Clarity of your syrup is obtained through good filtration. Ober remarked that gravity filters can be just as effective for small producers as a more elaborate system.
Color determines classification. “Each grade has a light transmission,” Ober explained. “Color changes occur as the sugar molecules change due to the introduction of heat. These changes happen very quickly and need to be monitored closely. Anything that interferes with flow of sap through the evaporator can cause the syrup to get darker and possibly cause an off-flavor.”
Minimize risk by monitoring your pans closely. Condensation will impact quality.
“Managing the level of sap in your pans is critical to avoid problems with density, color and flavor,” he said.
Foam management is also critical.
“Excessive foam in the back pan can cause problems with your float and may interfere with your ability to control the level of the sap in the evaporator. If this happens you will need to use a defoamer to control the problem. When using defoamer, the only place the defoamer should be added is at the point where sap enters the rear pan and occasionally a couple of drops, if needed, at the draw-off if foam builds up as you are drawing off,” he said.
Ober emphasized that defoamer should never be sprayed across the front pan to control foam. “Using defoamer in this manner will impede the boil and break down the gradient. This can lead to the dreaded big batch,” he said. “If the front pan is foaming excessively, then the foam is not being properly controlled in the back pan. Correct the problem back there. Use only small amounts of defoamer. Excessive use can result in an off flavor.”
Bacteria introduced through contamination will also negatively impact color and flavor.
“An overabundance of bacterial growth in the sap results in the formation of acids that can cause a sour smell and taste known as ‘sour sap.’ If boiled into syrup, the syrup often becomes thick and stringy, forming ‘ropey syrup,’” Ober explained.
Although this generally happens at the end of the season, Ober cautioned that it may occur at any time of the season, as it is influenced by environmental conditions and uncontrolled bacterial growth.
The four classifications are Golden (very light in color and generally collected at the season’s beginning); Amber (collected mid-season); Dark (generally collected as the season advances, and has a more robust flavor); and Very Dark (very strong taste and collected during the late-end of season).
Ober said folks are moving more and more toward using a spectrophotometer for determining the true color assessment for precise classification, and noted that new International Maple Syrup Institute grading standards continue to require a 66 brix.
Ober reminded producers that promptly and properly cleaning tubing and equipment and storing it at the season’s end is mandatory for production of quality syrup.
“When you start out the season you need to be aware of several problem areas that can lead to off-flavors. Most stem from equipment maintenance after the previous season and going into the new season.
“It continues with constant sanitation of equipment throughout the maple production process. A good example is replacing plastic sap storage tanks with easy to clean stainless steel tanks. Plastic tanks are one of the worst harbingers of bacteria because the plastic is porous and cannot be easily cleaned or sanitized. Many of the larger operations have now adopted new evaporator cleaning systems that clean not only the front pans but also the flue pan. This involves draining the back pan between runs and recirculating RO permeate water to remove niter and slow bacterial growth in the evaporator,” he said.
Ober mentioned he uses “a lot of water and elbow grease” to clean his systems and warns producers to be vigilant for mold growth in stored filters. If mold is observed, discard and replace the filters.
“Processing your syrup as quickly as possible is essential if you want to make a quality product throughout the season,” Ober said. “Making the highest quality product possible should be your goal. Your reputation as a maple producer depends on it.”
The 2019 NYS Maple Conference/Mid-Winter Maple Classic, coordinated by Keith Schiebel, was hosted by the New York Maple Producers Association, the New York FFA Alumni Association and Cornell University’s Maple Team.