What makes syrup light or dark

[Oxford]

I am curious as to what makes syrup light or dark. I’ve read that early season sap often yields lighter syrup while later sap gives darker syrup. I’ve noticed, myself, that when I store my sap for several days before boiling a batch on the weekend that it is usually much darker than when I boil sap harvested that same day. Is this because the microbes are at work converting the sucrose to glucose and fructose? Does storing my sap before boiling give the microbes more time to work? What has been your experience? I’m just a hobbyist producing a few gallons of syrup, but I’d like to learn more.

[DrTimPerkins]

Short answer, yes, it is the microbial inversion of sucrose to glucose and fructose, which are more active in Maillard and caramelization reactions, that is the largest factor in color and flavor development in maple syrup.

[Sugarmaker]

Welcome,
Cleanliness, boiling techniques/ speed of boil. temps of the stored sap, boiling same day gathered, type of pans/ evaporator, all of these can and will have an effect on final color. I always say that anyone can make dark syrup. Making the lightest syrup possible is a good goal.
Your statement is also correct. Most of the time lighter grades are made early, just not always! Have fun!
Regards,
Chris

[Russell Lampron]

Oxford in your case you are correct that the microbes are at work changing your sap as you let it sit. If making light syrup is your goal boil your sap as soon as you collect it and as fast as possible. If you can only boil on weekends keep your sap as cool as possible. There's nothing wrong with dark syrup either, most people prefer it now.

Sometimes it depends on the trees and the season too. I've seen dark syrup early and the lightest syrup at the very end and I've also seen it start out light, go to dark and go back to light again.

Cleanliness and processing techniques have a lot to do with it too. I used to blame my dark syrup on my red maples. I have since found that it was nitre burning in the flues of my flue pan. The excessive nitre in the flue pan was caused because of the high percentage that I concentrate my sap to with my RO. I solved that problem by building and installing an air injector. Now all of my syrup is Golden or Amber. It was the process and not the trees.

[billschi]

I solved that problem by building and installing an air injector. Now all of my syrup is Golden or Amber.
What do you use for a pump to inject the air?

[Russell Lampron]

What do you use for a pump to inject the air?

I use a small shop vac that I bought just for the air injector. I use it to blow instead of suck.

[slammer3364]

I have a small evaporator, I was under the impression that batching would give you darker syrup. I had a little sap and boiled it,I did not want to keep a heat lamp on it for 2 weeks so I drained it and finished it off,got 3 quarts of light amber.I always had to boil on weekends also but am now retired and can boil everyday we will see if it gets lighter. p.s. dark syrup taste great also!