Why does marmalade crystallize?

Marmalade crystallizes primarily due to the presence of sugar, which can form crystals when the concentration exceeds its solubility in the solution. This often occurs during the cooling process if the marmalade is not stirred adequately or if it's stored improperly. Additionally, factors like the type of fruit used, the cooking time, and the ratio of sugar to fruit can influence crystallization. To minimize this, proper cooking techniques and storage conditions are essential.