HOW TO CARAMELIZE SUGAR

Sugar is caramelized when it is melted into a clear golden to dark brown syrup, reaching a temperature from 320 to 350 degrees F. The example here is a medium amber.
 

To start, add some water to dry sugar in a pot, stirring, until it reaches the consistency of wet sand. The acid from added lemon juice will help prevent recrystallization. Instead of using lemon juice, you could add acidity with vinegar, cream of tartar or corn syrup. Always start with a very clean pan and utensils. Any dirt or debris can cause crystals to form around it.
 

Heat the pan over a medium flame. As the sugar melts, you can wash down the sides of a pan with a wet brush, which also prevents crystallization by removing any dried drops of syrup that might start crystals.
 

As the caramel heats, it colors in amber shades from light to deep brown.