A: Sugar syrups can be thermally processed without the need for a pressure process only if the water activity (Aw) is ≤ 0.85.  Water activity is measured using a water activity meter that typically costs $1500 to $4000.  A testing lab can provide this information for a fee.   Never reduce or remove the sugar in these types of products or the safety factor inhibiting botulism will also be removed.  You can get a process letter based on safe formulation achieving a water activity ≤ 0.85.