Recently, I was making buttermilk pancakes and could not find buttermilk in the store. For those who have not used buttermilk, it has a different outcome, when cooking and baking, from regular milk. Buttermilk is the sour liquid that remains after the butterfat has been removed from whole milk or cream by churning to make butter. Next time, if you are in a jam and cannot find buttermilk, a substitute can be made: add 1-3/4 tablespoons of cream of tartar to a cup of milk, or add a tablespoon of lemon juice or white vinegar to a cup of milk and let it stand for 5 to 10 minutes. This substitute should only be used as a last resort. Since, buttermilk is usually not used on a daily basis it is okay to freeze it and then use for baking and cooking when needed. It has been recommended only to keep frozen for three months.