What is the great problem that besets even the best fudge makers? Yes, the crystallization of their fudge. If you've ever made fudge (or anything based on a sugar syrup), you know that stirring when the sugar is held in suspension at high temperature can cause a massive crystallization, and result in grainy fudge.

All the Hershey's folks are asking for is a little patience. Yes, take the syrup from the heat. Add the butter and vanilla, but do not stir them into fudge until the mixture cools to around 100°F (38°C). Then, as you see from the recipe, they want you to actively beat all the ingredients together until it thickens, before cooling it further to room temperature.