When chocolate overheats, it can lose its smooth texture and become thick or grainy. I experienced this when melting chocolate for a dessert. If you heat it too much or too quickly, the cocoa butter in the chocolate can separate, causing a lumpy or grainy texture. It’s important to use gentle heat and stir frequently while melting chocolate. Also, avoid getting any water in the chocolate as it can cause it to seize, becoming stiff and unusable. Patience and low heat are key to smoothly melting chocolate for a delightful result in your recipes.