What is the purpose of cream of tartar when making boiled syrups?

Cream of tartar plays a crucial role in preventing crystallization when making boiled syrups. When sugar is dissolved in water and then boiled, the syrup reaches a supersaturated state, which can lead to sugar crystals forming as the syrup cools. The presence of cream of tartar, which is a form of tartaric acid, helps to stabilize the sugar molecules in solution, reducing the likelihood of crystallization. This is particularly important in recipes where a smooth, syrupy texture is desired, as unwanted crystals can lead to a grainy texture that is generally not appealing in syrups.

The other options don't align with the primary function of cream of tartar in syrup-making. Enhancing flavor, coloring, or increasing sweetness can involve other ingredients or processes, but they are not the reasons for using cream of tartar in this specific context.