Write an article based on this summary:

Substitute powdered buttermilk for liquid buttermilk. Bake your recipe as usual. Mix your buttermilk into the dry ingredients if a recipe calls for it.
If you're substituting powdered buttermilk for actual buttermilk, the amount you need will vary by brand. Check the label of your powdered buttermilk. However, as a general rule of thumb, you usually substitute 1/4 cup of buttermilk (60 mL) mixed with 1 cup of water (240 mL) for every cup (240 mL) of buttermilk in a recipe. When substituting powdered buttermilk for liquid buttermilk, follow the recipe as you normally would. Simply add your mixture of powdered buttermilk and water when you would normally add the buttermilk. The recipe should turn out more or less the same. Liquid buttermilk, or powdered buttermilk mixed with water, is usually added while you're mixing ingredients like eggs or butter. However, if a recipe calls for powdered buttermilk, it is added to the dry ingredients. For baked goods, you mix the buttermilk in with flour, baking soda, salt, dried spices, and any other dry ingredients used.