title_body: Has anyone tried infusing Torani sugar free syrup?
upvoted_answer: I have never personally tried but my advice would be not to heat it.
  
  In the same way that you wouldn't heat a shop bought sugar syrup - you will boil off the water and be left with a thicker syrup and possibly one which would crystallise. 
  
  You can either add the ingredients to your Torani's Syrup and leave for X days to see what happens, or follow a recipe to make your own! 
  
  Here is one I found for a sugar-free lavender syrup which you should be able to amend for a Ginger Cardamon version.