RO effect on grade?

[NW Ohio]

I've been thinking about for a couple of days and did not find an answer in a quick scan of the forum (seems like this may have been discussed before though).

Does using an RO make a better grade of syrup? I have been reading about the fact that a longer boil leads to darker syrup (true?), so it seems like taking out even half of the water might have a significant effect on grade. Any thoughts?

Thanks for any input.

[Snowy Pass Maple]

Yes, I think it's pretty well accepted that running a RO correctly, and cleanly, will increase the likelihood that you can make light syrup.

Using recirculation could in theory negate this somewhat as you'll be holding the sap longer before boiling, and it can get a bit warmer. But even recirculating, we find it's very easy to make light syrup with a RO that we only run up to about 6% typically. An upshot is that we don't have to worry about losing too much grade if we reheat for bottling later - lots of ways for syrup to get dark, but not many ways for it to get light.

[NW Ohio]

Please excuse my ignorance... ...but by recirculating do you mean running sap through RO more than once?

If this is the case, is the risk of recirculating and your concern for the sap getting "a bit warmer" due to the fact it would encourage bacterial growth? If so would passing the sap through a UV lamp prevent the bacterial growth and therefore also help the "grade"?