What type of agent is added to control crystal size in candy making?

In candy making, controlling crystal size is crucial for achieving the desired texture and mouthfeel of the final product. Cream of tartar is an acid that plays a significant role in this process. When added to sugar solutions, it helps invert some of the sugar, which reduces the chances of large sugar crystals forming. This inversion creates a mixture that contains both sugar molecules and syrup, leading to a smoother texture in candies.

Using cream of tartar assists in stabilizing the sugar syrup and encourages the formation of smaller, more uniform crystals, resulting in a desirable consistent texture. This essential function is why cream of tartar is often used in recipes for candies like fudge or fondant.