Not so sure about the sugar experiment now to be honest. In the comments here someone has pointed out that I can in fact just boil it down a bit and create a syrup which will last. In the end making it last is the goal, so I'm cool with syrup. Less effort!
Also, I didn't realise I could just grow sugar beets! Beets seem very happy in our soil so this could also be a solution to my sugar question.