Buttermilk

Buttermilk: Nutrition, History and Cooking Guide

Traditional buttermilk is the liquid remaining after churning cream into butter — low in fat but carrying the flavour compounds, phospholipids, and lactic acid from the churning process. In modern commercial practice, what is sold as buttermilk is almost entirely cultured buttermilk — low-fat or skimmed milk that has been inoculated with lactic acid bacteria (Lactococcus lactis and related cultures) and allowed to ferment, producing a tangy, thickened product that mimics the flavour of traditional buttermilk. Buttermilk has deep roots in baking traditions across Ireland, Scotland, and the American South, where the acidity of buttermilk reacts with bicarbonate of soda (baking soda) to produce carbon dioxide, giving rise to soda bread, Irish brown bread, American biscuits, and Southern buttermilk pancakes. The buttermilk tradition in Irish cooking is particularly ancient — sour milk and buttermilk were staple foods in the Irish diet for centuries, used in breads, drinks, and as a everyday beverage on farms.

Nutritional Value of Buttermilk

Cultured buttermilk provides 56 kcal and 4.1 g of protein per 100 ml, with 2 g of fat — a nutritious, low-fat cultured dairy product. It provides calcium (around 116 mg per 100 ml), iodine, phosphorus, potassium, B12, riboflavin, and the beneficial lactic acid bacteria of fermented milk. The lactic acid gives it its characteristic tang and may contribute to gut health benefits typical of fermented dairy products.

Health Benefits of Buttermilk

Buttermilk provides the core nutritional benefits of milk — calcium, iodine, protein, and B12 — in a low-fat, tangy form. As a cultured product, it contains lactic acid bacteria that may support gut microbiome health, though most of these bacteria do not survive stomach acid to reach the large intestine in the quantities found in dedicated probiotic products. Its low fat content and protein content make it more satiating per calorie than many beverages. The acidity also makes it a tenderising marinade ingredient — it denatures muscle proteins and penetrates meat or poultry, producing tender results in fried chicken, buttermilk-marinated grilled meats, and similar preparations.

How to Use Buttermilk

For baking: replace regular milk with buttermilk and add bicarbonate of soda (half a teaspoon per 240 ml buttermilk) for a leavening reaction. Essential for soda bread, scones, and American biscuits. For marinades: soak chicken in buttermilk overnight before frying — the result is dramatically more tender. For dressings: buttermilk is the base of ranch dressing and blue cheese dressing. Substitute: mix 240 ml of milk with a tablespoon of lemon juice or white vinegar, stir, and leave for five minutes — an effective emergency substitute.