Too many variables. The biggest being temperature, followed closely by the sanitation practices. If in bucket collection, with good clean buckets 1 day is safe at 50F but barely. The best way to judge it is clarity, if the sap is still clear it's good,
However cloudy sap will still make good syrup, just not as much as when it was clear. Once it gets cloudy , that is caused by micro-organisms which are feeding on the sugar in the sap.
To keep sap fresh the longest you need to keep it cool.
I will not even attempt to make a chart for the progression of sap degradation, but Proctor may have one.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.