Milk chocolate is a form of chocolate that is blended with milk for a more mild, creamy flavor than dark chocolate, which is composed primarily of cocoa liquor. Many candy companies use it for their products, which are designed to be eaten out of hand, and this type of chocolate can also be used in some baking applications. If you want to use it in baking, make sure to use a recipe which has been designed for milk chocolate, as it behaves very uniquely during baking, and it is also extremely heat sensitive.
Before delving into milk chocolate, it may help to become familiar with basic chocolate terminology. Chocolate is derived from the seeds of the cacao plant, Theobroma cacao. The seeds or “nibs” are formed in large pods, which are harvested when ripe. Harvesters split the pods to access the seeds and then ferment them for around a week before roasting and grinding them to release their chocolate liquor. Chocolate liquor is composed of cocoa solids and cocoa butter, the fatty part of chocolate.
Pure chocolate liquor is turned into baker's chocolate. If you have ever bitten into a piece of baker's chocolate, you also know that it is extremely bitter, due to the alkaloids in chocolate. Therefore, chocolate liquor is often mixed with sugar and other ingredients to make candy bars and other sweet chocolate products.
Typical milk chocolate includes 10% chocolate liquor, along with an additional percentage of pure cocoa solids; in Europe, it must contain at least 25% cocoa solids. Around 12% contains milk solids, and another 3.7% is composed of milkfat. Sugar and vanilla are also added to make this chocolate creamy and to enhance the flavor. Either condensed or powdered milk may be used, depending on the manufacturer.
The quality of milk chocolate varies widely, just as the quality of other forms of chocolate does. Well handled nibs and high quality milk and sugar will create a product with a superb mouthfeel and flavor, while poor ingredients will yield a grainy, bitter, slightly sour chocolate. Different regions of the world have their own formulation preferences, depending on the techniques used by major candy producers to create their products. You may have discovered this when traveling. If you feel like having an interesting blind taste test, assemble different regional incarnations of the same candy bar and try identifying the differences in the chocolate formulations used.