The ideal temperature for sugars and pectin to bind together is 220°F. While slow cookers may vary, my batches never reached this temperature even after testing one for 6-8 hours. After so much time, the sugars start to caramelize and the slow cooker jam starts to turn brown. Not only is it unpleasant to look at, but it doesn’t taste very good either! For best results, cook for 2-3 hours while stirring regularly — this helps distribute the sugar and ensures that it dissolves completely.