The buttermilk used in modern baking recipes is usually cultured acidic milk rather than simply the liquid left from making butter. Traditional buttermilk was the thin liquid remaining after cream was churned, but King Arthur explains that today’s commercial product is generally milk inoculated with bacteria that produce lactic acid.
That acidity matters because it affects flavor, leavening chemistry, and the texture of batters and doughs.
Why does buttermilk often appear with baking soda?
Baking soda is alkaline. When it meets an acidic ingredient such as buttermilk, yogurt, or lemon juice, it reacts and releases carbon dioxide.
Those gas bubbles help pancakes, biscuits, and cakes rise. Replace buttermilk with plain milk in a recipe that depends on soda and you remove some expected acidity, potentially changing rise, browning, and flavor.
Acidity also changes texture
Buttermilk supplies water, milk proteins, sugars, and acid. In wheat-based batters, its acidity and dairy solids can contribute to a tender crumb and a less dry eating texture.
King Arthur also reports that dried buttermilk supports tenderness and moisture retention in baked goods while adding richer dairy flavor.
Buttermilk does not taste exactly like randomly soured milk
Bacterial culturing produces lactic acid plus other fermentation compounds. The result is tangy but also milky and relatively rounded.
Milk mixed with vinegar can reproduce part of the functional acidity, but it does not fully reproduce the flavor or viscosity of cultured buttermilk.
Thinned yogurt is one of the strongest baking substitutes
King Arthur tested several options and found Greek yogurt thinned with milk performed especially well in pancakes and biscuits. Add enough milk or water to reach roughly the consistency of light cream.
Plain unsweetened kefir also works well because it is already a fluid, acidic fermented dairy product.
Milk plus lemon juice or vinegar works, but it is not identical
A common emergency substitute is roughly one tablespoon vinegar or lemon juice added to one cup milk and left for 10–15 minutes. The milk acidifies and may thicken slightly.
This is useful when the main job is reacting with baking soda, although flavor is usually less complex than cultured buttermilk or yogurt.
Do not ignore acid-base balance in a soda-leavened recipe
A baking-soda recipe is formulated with a certain amount of acid in mind. Replacing buttermilk with neutral plant milk or regular milk without adjusting leavening can change both pH and lift.
If a recipe relies mostly on baking powder and includes only a small amount of buttermilk, the substitution may be less dramatic.
Can buttermilk be used in savory cooking?
Yes. It appears in marinades, dressings, fried chicken, biscuits, and savory batters. Its acid adds flavor and can modify proteins on the surface of meat during marination.
It can also replace some milk or yogurt in cold sauces, although strong direct heating may cause separation if temperature is poorly controlled.
Dried buttermilk is another option
Shelf-stable buttermilk powder preserves the acidic dairy component for longer storage. King Arthur uses roughly 30 g powder plus one cup water or milk for each cup liquid buttermilk, following product directions.
The practical rule: when a recipe calls for buttermilk, think acid plus liquid plus dairy solids. Thinned yogurt or kefir reproduce those functions well; acidified milk handles the chemical part when nothing else is available.
The exact product can vary across brands and countries, especially in acidity, fat, salt, and moisture. When a recipe depends heavily on one of those properties, the label and actual texture are better guides than assuming every version behaves identically.
The exact product can vary across brands and countries, especially in acidity, fat, salt, and moisture. When a recipe depends heavily on one of those properties, the label and actual texture are better guides than assuming every version behaves identically.
The exact product can vary across brands and countries, especially in acidity, fat, salt, and moisture. When a recipe depends heavily on one of those properties, the label and actual texture are better guides than assuming every version behaves identically.
Sources
- King Arthur Baking — Buttermilk Substitute: What to Use — Explains traditional versus cultured buttermilk, its acidity in baking, and tested substitutes including yogurt, kefir, and acidified milk.
- King Arthur Baking — Baking Soda vs. Baking Powder — Explains that baking soda requires acid such as buttermilk to produce carbon dioxide for leavening.
- King Arthur Baking — Dried Buttermilk — Describes dried buttermilk as a shelf-stable baking substitute and discusses tenderness, browning, moisture, and flavor.