And now for the tough part: the waiting! While the cherries can be enjoyed as soon as the chocolate is hard, to get liquid centers you will have to wait anywhere from a few days to a few weeks. (The exact time depends on the strength of your invertase.) Store the cherries at warm room temperature during this time—cold temperatures will slow the working of the invertase. You can start testing the cherries after 2-3 days, and continue to monitor their progress via the occasional taste test until the centers are completely liquid.