|A type of milk that is most often used as an ingredient to enhance baked goods with a rich tangy flavor. Buttermilk produced on dairy farms is the liquid that remains after the butter has been separated from whole milk. However, commercially produced buttermilk is cultured Buttermilk manufactured by adding lactic acid bacteria to a non-fat or low-fat milk after the milk is fermented with heat. Buttermilk is often thought of as "sour milk" and is a common ingredient in many recipes. It can be created in a substitute form by adding 2 tablespoons of lemon juice or vinegar with 3/4 to 1 cup of whole or soy milk. Another substitution option includes adding 2 teaspoons of cream of tartar to 1 cup of milk.|
Buttermilk can also be purchased in a powder form to which water is added to liquidify it. Instead of water, low-fat milk can be substituted to fortify the powdered form with added calcium. Since the bacteria that may be harmful has been removed during the heating and fermentation process and since lactic acid has been added which helps to prevent bacteria from growing, the Buttermilk can be kept for longer periods of time in the refrigerator. As the Buttermilk ages, the lactic acid increases and begins to eventually sour the milk which may cause it to curdle. As it sours, it becomes inedible and indicates it is time to discard any remaining Buttermilk.