Could well be as the sap I collected towards the end of the season was cloudy and a little green but did not have a bad taste to it,,in the past I have tasted sap that just tasted awful,,but this stuff really did not,,,,,BUT my pans were empty and washed befor I started boiling the last of the sap,,and no sap sat in the tanks for more than 12 hours?,,,,I did notice that my flue pan would have a bunch of stuff floating in it thru the sight glasses,,,(suspended solids),,and I would like to figure out how to avoid this in the fucther,,only happend 3 times this year,,but when I see that I know I have to clean the pans,(or no matter what kind of sap I put into the evap. I will be making commercial syrup),,just hate to dump all that sap (200-300 gallons) to wash them,,a fellow told me that not skimming the flue pan is the cause of the floaters,,I have a flat hood on the fluepan so no skiming,,I do have 2 felt filters that the sap goes thru befor it enters the evap,,,and we washed the tanks after every boil???