Once again I’ve come across this issue. This time I actually have syrup going moldy in the bottles. Different supplier this time but I’m assuming they all get their bottles from the same manufacturer.
I’ve been bottling them same way.

-Syrup at 185 even double and triple checked with different thermometers
- Fill bottle to just under the threads. Leaves about 1/2” to top of bottle open
- place cap on and tighten.
- turn bottle on side for 10 minutes then stand up.

Had no problem at all in 2020 and 2021. But now it’s back.

Called the supplier and they asked me if I was placing bottle on its side after installing cap. I said yes of course.
They said that I should not do that. And that’s why I’m getting leaks and not getting a proper seal. The temperature of the syrup is overheating the cap material. Was told to fill bottle to within 1/4” of top and place cap on and done.

#1. Ontario regulations for hotpacking syrup states that I have to turn bottle on its side and recommends preheating the bottles.
#2. Why is a maple equipment company selling a maple bottle and cap that is not suitable for temperatures to be able to hot pack syrup.