Why maple syrup colour changes through the season

There aren’t too many natural products with four distinct colours.

Maple syrup changes from a light golden colour to a deep dark brown through the season because rising spring temperatures increase microbial activity in the sap. That is why maple syrup is graded by colour, with each grade reflecting the point in the season at which its sap was collected.

The trees themselves do not change; it is the sap and what happens to it that makes the difference.

How exactly this happens is worthy of an article. So, let’s discuss the wonderful variety of maple syrup.

The science behind the colour change

Here we get into the specifics of how and why maple syrup is found in various colours.

Bacterial and yeast action

As winter turns to spring and weather warms up, bacteria and yeast multiply in the sap collection lines and taps. These microorganisms are a natural part of the sugaring process and are removed when the sap is boiled.

Invert sugars

These microbes break down sucrose (complex sugar) into simple sugars called invert sugars, specifically glucose and fructose. The longer the season runs and the warmer it becomes, the higher the proportion of invert sugars in the sap.

The Maillard reaction

When the sap is boiled down, these simple sugars caramelise and react with amino acids much more easily than sucrose. This creates a darker colour and richer flavour through the Maillard reaction (the same browning process that happens when toasting bread).

Seasonal progression and grades

Now we’ll run through the maple season – also known as the sugaring season – stage by stage, tracking how the colour of the product changes.

Early season (Golden / Delicate)

Tapped during freezing nights and cold days; yields a light colour and subtle flavour. Our Golden Delicate syrup is ideal for drizzling over pancakes, yoghurt and desserts.

Mid-season (Amber / Rich)

Tapped as conditions moderate; yields a classic rich taste and medium amber colour. Amber Rich is a versatile, everyday syrup.

Late season (Dark and Very Dark / Robust)

Tapped when weather turns warm and trees begin to bud. The late season yields a dark, robust syrup. Dark Robust holds its flavour well in baking, glazes and marinades.