A couple of things, pack the jugs at 185, 190 is even safer, get the right wrench to tighten the caps, make sure the seal in the cap is not damaged before you use it and then tip the container on it's side for at least a minute as soon as the jugs is filled. Then you should be fine. The problem is not likely the jug but rather those other factors. If the syrup was at the correct density it will store without spoilage. Even 2-3 or 4 years should not be a problem.
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.