Old-fashioned white gravy starts with meat drippings. For biscuits and gravy, the meats of choice include browned sausage or bacon. At the dinner table, white gravy usually accompanies fried chicken or chicken-fried steak. In all its incarnations, white gravy could hardly be called a health food, but it is a satisfying addition to hearty, stick-to-your-ribs food. Don't use water to make white gravy, which will ruin its rich taste. Stick with milk, cream or other dairy substitutes.
You can thicken any gravy with a flour and butter roux, or a slurry made from cornstarch mixed with water, but the liquids you use distinguish a white gravy from a brown gravy. White gravy always contains some type of dairy product, while brown gravy is made from meat drippings and juice combined with water or broth. You can make a gravy using water, but it won't be white and it will lack the thickness, flavor and body of gravy made with milk. Chances are, you'll be sorely disappointed.
Exceptions to the Rule
There's an exception to every rule in the kitchen, including making white gravy. If you use a packaged white gravy mix, the directions will likely instruct you to combine the packet with cold water. Most mixes contain powdered milk and buttermilk solids so you can get away with using water. But even in this case, the gravy will be creamier if you add some milk.
Substitutes for Milk
If you're out of milk, you can substitute reconstituted powdered milk, evaporated milk or cream diluted with a bit of water to make white gravy. If you're trying to avoid milk and other dairy products, use a nondairy substitute, such as soy milk, almond milk or rice milk. Use the same amount of a substitute as you would milk -- typically 2 cups.
Making Homestyle Gravy
Making white gravy is no different than making brown gravy, except in your choice of liquid. Brown the sausage or bacon, reserving the drippings. You can also use the drippings from oven-fried chicken or chicken-fried steak. Heat the drippings in a large skillet over medium heat and whisk in some flour. Continue whisking until the flour turns light brown. Stir in most of the milk and whisk until smooth. Stir in the remaining milk and bring the gravy almost to a low simmer. Don't boil the gravy, which can cause the milk to separate.