The art of substitution in cuisine is fickle. Sometimes it's easy to leave out an ingredient if the taste is undesirable, while other omissions can ruin an entire recipe. Most of the time, substituting coffee creamer for milk in a recipe won't present a problem, though some instances make it necessary to stick with the real thing.
The Role of Milk
Milk is used in recipes for various reasons. In baking, it is used as a liquid to bind ingredients. It can be a base liquid in a meal to create a creamy, rich dish or added sparingly at the end to lighten a dish. To determine if coffee creamer can be a substitute for milk in your meal, figure out the purpose of the milk in your particular recipe.
In the majority of recipes, replacing milk with coffee creamer won't have much of an effect on the end product. For example, if you are making a white gravy and want to try a nondairy version, go ahead and use coffee creamer. If the milk is a baking liquid, substitution is not an issue. Coffee creamer can even be used as a milk substitute in custards and other creamy desserts. This is done commonly for different reasons, such as creating a kosher Thanksgiving spread. Note that it can have an effect on taste and texture, so avoid flavored or sweetened creamers in savory dishes.
If you are trying your hand at making yogurt, this is one of the few times coffee creamer can't be substituted, though it is possible to make yogurt with other types of milk such as coconut milk. Coffee creamer won't work for cheeses either. These recipes need lactose and whey proteins to work properly, so adding in something different won't do the trick. Instant pudding is another instance in which milk substitution doesn't work.
Different Types of Milk
While nondairy and dairy-based creamers make acceptable milk substitutes, other great substitutes are also out there. Soy milk, rice milk, different kinds of nut milks, oat milk, coconut milk, evaporated milk, powdered milk and goat milk all have something to offer, each contributing its own distinctive texture and flavor to a recipe. Rice milk, for example, will create an icy and hard frozen dessert in an ice cream recipe, whereas coffee creamer will be perfectly rich and creamy. When substituting, determine the qualities that are most important and make the best decision based on the desired outcome.