I love maple syrup, so was delighted to attend the Sweetwater Harvest Festival last weekend at Wye Marsh Wildlife Centre and Sainte-Marie Among the Hurons. While touring the Wye Marsh sugar shack, I learned (part of) the answer to a question I had never thought to ask, but should have: why does maple syrup come in different colours?

---

Here is a view of the Wye Marsh sugar shack, in the off season, to set the scene.

In Ontario, maple syrup comes in four classes, determined by the amount of light which passes through: golden (delicate taste), amber (rich taste, my favourite), dark (robust taste, good for baking), and very dark (strong taste, a class I’ve rarely seen for sale).

I’d presumed that the colour had to do with the concentration (more boiling = darker syrup?), or perhaps where the sap was obtained, or having come from different varieties of maple tree. But no!

The Wye Marsh guide explained that the colour has to do with the time in the season at which the sap is harvested. Sap from early in the season produces golden maple syrup, and the colour gets darker as the season (usually 4-6 weeks long) progresses.

Great… but why?

The answer is microbes (bacteria). Per The Art of Doing Stuff, “As the season progresses and temperatures rise, bacteria in the sap increase. This bacteria converts sucrose into fructose and glucose, which caramelize more easily during boiling, resulting in a darker syrup” (source).

Of course, there’s a lot more to it. See The Science of Syrup by Audrey Clark.

Now that I know, I’m hoping to do more testing at a few more maple festivals this year, just to be sure. 🍁

 

Top photo credit: Dvortygirl under CC BY-SA 3.0 licence