Maple Grades, Quality & Flavour

Understanding Maple Syrup Grades

When you pick up a bottle of maple syrup off the shelf, the only information that will give you any idea of what that syrup will taste like is the grade. The grading of maple syrup has changed significantly over the past decades, and while experts have established internationally agreed-upon grades, the old grading system persists on bottles and in the minds of some consumers. 

Unfortunately, the grading system makes no effort to enlighten people on the array of flavours and faults that can be found in maple syrup. Independent grading agencies will test syrup and reprimand producers for syrup that contains a fault, but nothing stops the packers who bottle the majority of the world's maple syrup from using a percentage of faulted syrup in their generic blends. 

The following is an attempt to describe the grades, flavours and faults found in maple syrup.  We hope it helps you to understand the range of maple syrup's qualities and characteristics, and encourages you to appreciate its many subtleties. 

Determining Light Transmission in Maple Syrup

To measure light transmission in maple syrup, we use a spectrophotometer with matched square optical cells that have a 10mm light path at a wavelength of 560nm – the wavelength of yellows. It expresses colour values in percentage of light transmission. Using a wavelength visible to the human eye, we determine what percent of light being shone at a vial of maple syrup is able to pass through it. The darker the syrup, the lower the percentage of light transmitted. The lighter the syrup, the higher the percentage.

The old grading system uses light transmission to characterize syrups according to the following categories. The grades, listed below, account for class, colour, and percentage.

1. AA, Extra Light: 75% or more
2. A, Light: 60.5% or more but less than 75%
3. B, Medium: 44% or more but less than 60.5%
4. C, Amber: 27% or more but less than 44%
5. D, Dark: less than 27%

The new grading system also uses light transmission to categorize syrups, but within wider ranges. This makes sense, considering syrup can naturally darken over time. The grades, listed below, account for colour, taste, and percentage.

1. Golden, Delicate Taste (Doré, goût délicat) no less than 75.0%
2. Amber, Rich Taste (Ambré, goût riche) less than 75.0 but no less than 50.0%
3. Dark, Robust Taste (Foncé, goût robuste) less than 50.0 but no less than 25.0%
4. Very Dark, Strong Taste (Très foncé, goût prononcé) less than 25.0%

In addition to measuring light transmission, producers must bottle maple syrup at a specific density of 66 degrees brix or greater (if the syrup is concentrated too much, however, it can crystallize).

Learn more about light transmission in maple syrup in our blog post here.

Maple Syrup Flavours

There's a science to tasting maple syrup. Specially trained practitioners (known as sensory evaluators) from Agriculture & Agri-Food Canada (AAFC) and maple product scientists from Centre ACER have developed tools to explore the range of maple flavours and characterize the taste and smell sensations that maple syrup produces.

Their Flavour Wheel of Maple Products (below) was developed from a list of approximately 250 reference characteristics provided by several tasting panels. It provides a scientific basis for objective, reliable descriptions of the many tastes of maple syrup. Like a dictionary, it establishes a common language for producers to discuss and describe complex flavours in detail and with a high degree of accuracy.




Maple Syrup Faults

As previously mentioned, colour and grade only tell part of any maple syrup's story. Yet, unless one or more serious faults is identified prior to bottling, additional factors of taste and quality are not communicated to those who are buying the syrup. Understanding potential faults in maple syrup and why they occur is critical for maple syrup producers, but we think it's also important for discerning consumers! 

The following determinable faults were published by the Cornell University Maple Program.

Musty: this off-flavour can become present when hot syrup is run through filters that contain mold, or when syrup is stored in poorly sealed containers. It tastes yeasty or moldy, and usually has a moldy odour.
Ferment: fermented syrup will have a sickeningly sweet flavour that, depending on the type of ferment, may be honey-like, alcoholic or fruity to the taste. Severe ferment may create a foamy appearance. Ferment usually develops from one of two problems: 1) if syrup has not been concentrated to the correct amount of sugar, yeast can begin fermenting sugars into alcohol; or 2) if syrup is stored in improperly cleaned barrels, fermentation can occur even in syrup with the correct density. Even steam-cleaned barrels can retain enough moisture to foster yeast, mold, and bacteria in great numbers.
Sour sap: as the weather warms near the end of the sugaring season, any sap left in a tank begins to warm and spoil. Syrup made from this sap has a stringy appearance when poured, and the flavour is very sour.
Burnt niter: when sap is boiled, minerals precipitate out to form niter. This niter collects in the compartment in the front pan where the syrup is drawn off and, if left to build up, can rise up and burn the syrup. This creates a combination off-flavour: a burned taste and a niter taste with a slightly fizzy effect. This can be prevented by switching draw-off sides frequently, or changing front pans. 
Scorch: this off-flavour creates a burned taste, caused when low levels of syrup in the front pans are burned in the evaporators. 
Earthy flavour: tapping into punky wood, cracked wood, or dark-coloured/stained areas in a tree produces syrup with this off-flavour, which tastes and smells like garden soil. Careful tapping can prevent this fault. 
Metabolism: this off-flavour is attributed to changes in the metabolism of trees when temperatures warm, which can occur at any time in the sugaring season. A metabolism off-flavour robs the syrup of most of its maple flavour, leaving a taste likened to wood, peanut butter, or popcorn. A cardboard-like flavour or chocolatey smell may also be present.
Buddy: buddy syrup is usually produced during the late season, depending on weather conditions. When trees begins to produce buds, their sap takes on a distinctive quality that is then transferred into the syrup. Buddy syrup usually tastes chocolatey, almost like a tootsie roll. If very strong, it may taste slightly bitter.