We are brewing a vanilla maple oatmeal stout, and its still in the boil phase, but I was curious about adding pure maple syrup to either a cold crashed secondary, or carbonating with it. How much maple syrup should I use for a 5 gallon batch to carb? If I cold crash, is there a way to do so without completely killing our yeast colony so we could still carb at bottling (we haven't yet upgraded to a keg setup)?