We want to try making marshmallows and the recipe says to cook the syrup to the "hard ball" stage. What does that mean?
When you cook the sugar syrup, it will hold it's ball shape, but is still sticky. The traditional way to measure this was to drop a small spoonful into a bowl of ice water and, while staying in the water, use your fingertips to form a ball. A more precise way to measure that is to use a candy thermometer, and cook the syrup to 250-260F degrees.
Recipe: Toasted Coconut Marshmallows