Like Haynes said as long as you don't expose the solder you will be ok. To do so don't use acid cleaners and when srubbing with scotch pads don't spend alot of time on the solder. Another thing to keep the lead down in the syrup is to reduce the contact time, so when you are not boiling drain the pans. Or maybe drain them if you aren't going to boil the next day.
Keith