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Understanding Maple Syrup Grades

Updated: Mar 10, 2023

maple grades, quality & flavor

Stack of small glass bottles of maple syrup in different shades of yellow, orange, and red
Vermont maple syrup samples

Whether you get your Vermont maple syrup direct from a farm, at the grocery store, or at your local foods co-op, you've probably noticed that maple syrup comes in different flavors and colors. The jug will have a sticker on it that says Golden Delicate, Amber Rich, Dark Robust, or Very Dark Strong. These labels give you an idea of the flavor of syrup inside that jug. This means that all Vermont sugarmakers can make similarly flavored maple syrup - and you get the flavor you want everytime, no matter who you buy the syrup from. But it's not quite that simple- because every batch of maple will have a slightly different flavor from every other batch.

Just like in wine, different sugarbushes will produce slightly different flavors of maple syrup. And from day to day, we notice flavor changes in our syrup. Some days the syrup tastes buttery. Some days there are notes of toasted marshmallow. We'll get into flavor variations more below. But as a general guide, the grading system is a useful for choosing maple flavor. Lighter maple syrup has a lighter flavor. Darker syrup has a much richer taste.

In this post we'll describe the grades, flavors and defects that can be found in maple syrup. We hope it helps you understand the diversity of maple syrup, and helps you to appreciate the terroir of individual sugarbushes.

part 1: color & maple syrup grades

What does light transmission have to with maple syrup?

Maple is graded using a two-part system. The first step is color, measured by light transmission through syrup. The scientific process uses a spectrometer, a tool that measures light wavelength. Maple syrup has legally defined density requirements, so these light transmission requirements are taken at a specific density of 66 degrees brix. The percentage of light able to pass through a maple sample correlates to maple grade. Darker syrup allows less light to pass through. Lighter syrup allows a higher percentage to pass through.

1. Golden, Delicate Taste: at least 75% light transmission

2. Amber, Rich Taste: 50% - 75% light transmission

3. Dark, Robust Taste: 25% - 50% light transmission

4. Very Dark, Strong Taste: less than 25% light transmission

Hand holding a wooden box with four small glass jars. Window in background shows green grass and a tree..

Most sugarers buy a color-matching grade kit instead of using a spectrometer. The kits have small sample jars filled with dye and glycerin. That day's maple syrup is placed in a fourth jar, then put into the grading kit so the samples run from darkest to lightest. The dyed glycerin samples correlate to very dark, dark, and amber. Syrup must be lighter than the jar to the left of it to be that grade. There is no golden sample because there is no limit to how light maple syrup can be.

But why does the color of maple syrup vary so much?

Most of the sugar in sap is sucrose. When sap touches air- such as in a maple bucket - naturally occuring yeast and bacteria break sucrose down into the smaller molecules fructose and glucose. The warmer the temperature, or the longer sap waits to get collected, the more sucrose gets converted. Fructose and glucose go through a Maillard reaction, or browning, when exposed to heat. Sucrose doesn't. The more fructose and glucose in the sap and the longer the sap boils, the darker the syrup.

Sap with lower sugar content and/or lower pH will also result in darker syrup. Lower pH facilitates sucrose conversion. Lower sugar content in sap means the syrup has to be boiled longer to achieve proper density, allowing more time for the Maillard, or browning, reaction.

This is why many sugarmakers think Golden is the ultimate syrup. It takes more effort and luck to make light syrup than to make dark. You need the perfect alignment of conditions: high sugar sap has to be cold, stored in sanitary containers, and collected quickly. A beautiful light batch of syrup is always exciting to draw off the pan.

eight glass jars with different colors of maple syrup in them.

part 2: flavor & maple syrup grades

There's a lot of science behind color grades of syrup. Flavor grading is more of an art.

A sugarmaker can decide the flavor of syrup is darker than the color, and move the syrup down a grade. For example, a very strong flavored syrup that is the color of amber rich can be sold as dark robust. The opposite is not true: a delicate flavor cannot move an amber colored syrup into golden.

There is a lot of scientific research into flavor compounds of maple, and this has produced a lot of useful tools for sugarmakers who want to describe the flavor of their syrup in more detail. But it all comes down to the complexity of conditions in a specific sugarbush on a specific day. Science helps us understand how it happens. Art comes into play when we describe it.

We use a chart from University of Vermont to help us describe the flavors from each batch. We've mostly noticed toasted, confectionary, and milky flavors. Higher intensity show up in darker syrup. Try using this chart next time you have syrup. It may help you describe flavors you didn't notice before.

maple syrup off-flavors

It's unlikely you'll come across any of the following flavors unless you're making your own maple syrup. Cornell University Maple Program published this list to help sugarmakers avoid selling low quality maple syrup. The presence of any of these flavors means that batch of maple shouldn't be sold.

Musty: syrup tastes yeasty or moldy, and has a moldy odor. Usually this happens when syrup is stored in an unsealed container or run through moldy filters.

Ferment: fermented may be honey-like, alcoholic or fruity to the taste, and often will have a foam at the top. This is usually caused by syrup that is boiled too thin or stored in dirty containers. Severe ferment may create a foamy appearance. Fermentation is caused by yeast, mold, and bacteria.

Sour sap: Syrup will have a ropey appearance and taste sour. This is caused by sap that overheats and starts to spoil before boiling. This is more common during hot days at the end of sugaring season.

Burnt or Scorched: Burnt syrup will have a defined burnt flavor. When sap is boiled, minerals precipitate out to form niter. If the front pan isn't regularly cleaned during sugaring season, niter collects in the at the bottom of the pan and can burn syrup. Burnt flavors also happen when low levels of syrup in the front burn off before fresh sap can come into the pan.

Earthy: Earthy syrup will smell and taste like soil. This happens when a tree has a tap placed in damaged wood, such as punky or dark-stained parts of the tree.

Buddy: Buddy syrup has bitter chocolate notes. Buddy syrup is produced at the end of sugaring season, and often signals it's time to stop collecting sap for the year. When trees begins to produce buds, their sap takes on a distinctive quality that is then transferred into the syrup.

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