Rarely, the spread can develop a grainy texture over time. This happens if the sugar has not been completely melted and dissolved during the heating step. Even just a few stray sugar crystals can make it so that the rest of the sugar slowly crystallizes, leading it to have a grainy texture. You might not notice it when it is freshly made, but over time you’ll see and taste the spread becoming more granulated. It’s still perfectly safe to eat, but most people don’t enjoy the crunchy texture. Fortunately, it’s easy to fix the grainy texture. Transfer the chocolate spread to a bowl and heat it in the microwave in 30-second increments, whisking well and checking it for sugar crystals after each interval. To check, rub a bit of the chocolate spread between your fingers to see if you feel any sugar crystals. When the spread is warm and you can find no trace of sugar crystals, pour it back into a container, place plastic wrap on top, and let it cool completely.