Buttermilk-Originally, buttermilk was the liquid left behind during the process of churning butter out of cream. The term buttermilk also refers to a range of fermented milk drinks. This fermented dairy product known as cultured buttermilk is produced from cow’s milk and has a characteristically sour taste caused by lactic acid bacteria. Commercially available cultured buttermilk is milk that has been pasteurized and homogenized and then inoculated with a culture of Streptococcus lactis plus Leuconostoc citrovorum to simulate the naturally occurring bacteria in the old-fashioned product. The tartness of buttermilk is due to acid in the milk.
To make a close resemblance of buttermilk for use in a baking recipe, simply add 1 tablespoon lemon juice or vinegar (white or cider) plus enough milk to make 1 cup. (let stand 5-10 minutes) Or substitute 1 cup plain or low fat yogurt or sour cream as a straight up substitute in the recipe. If you buy powdered buttermilk found in most supermarkets, you will add 1 cup water to 1/4 cup buttermilk powder. And lastly if you happen to have Cream of Tartar you can add 1 3/4 teaspoons to 1 cup milk.
1 Cup Buttermilk = 8fl oz