If chocolate comes into contact with even the tiniest amount of water while melting, it will suddenly "seize," or turn hard and grainy. A single drop of water or a whiff of steam can trigger particles in cocoa butter to solidify into a dull mass. Ironically, adding more liquid will help smooth the chocolate back to its former satiny texture.
Remove the pan from the heat.
For every ounce (30 g) of chocolate, add 1 tbsp. of one of the following ingredients, depending on the recipe you are making: warm water, melted butter, vegetable oil, or hot milk or cream.
Stir or whisk until smooth. Slowly add more liquid if needed.
Chocolate recovered from seizing should be incorporated with other ingredients to make sauces, frostings or batters. It is not suitable for using alone, such as for coating candy or creating decorative curls (it won't have the same shine or delicate texture).
Before you start melting chocolate, add 2 tsp. liquid for every ounce (30 g) of chocolate to prevent seizing. For best results, use one of the liquids in the recipe.