Why does frosting crystallize?

Frosting crystallizes primarily due to the formation of sugar crystals when the sugar syrup cools too quickly or when there's not enough moisture. This can happen if the frosting is overcooked, or if it’s stirred too vigorously, which can introduce air and create a grainy texture. Additionally, using granulated sugar instead of powdered sugar can increase the likelihood of crystallization. To prevent this, it's important to maintain the right temperature and technique when preparing the frosting.