What does buttermilk mean?
Buttermilk is a tangy, slightly thick dairy product used extensively in cooking and baking. Traditionally, it was the thin liquid left over after cream was churned into butter — a mildly sour by-product that farm households valued rather than wasted. Today, most commercial buttermilk is made quite differently: low-fat milk is inoculated with lactic acid bacteria and allowed to ferment, producing the same characteristic tartness and viscosity. Its acidity reacts with leavening agents such as baking soda, which makes buttermilk prized in recipes for pancakes, biscuits, cakes, and fried-chicken marinades, where it lends tenderness and a subtle tang. The name is something of a misnomer, since buttermilk contains little fat and no actual butter. In American cuisine, especially Southern cooking, it carries warm associations of home-style comfort food, while its clean, sour flavor has also earned it a place in dressings, smoothies, and cold summer soups across many culinary traditions.
nounThe slightly sour, thin liquid left after churning cream into butter; in modern commercial production, a cultured milk made by fermenting low-fat milk with lactic acid bacteria.
- The tangy, fermented low-fat milk widely used in baking and cooking, produced commercially by adding lactic acid bacteria to milk.
- The thin, slightly sour liquid remaining after cream has been churned into butter (traditional buttermilk).
"The pancakes turned out exceptionally tender thanks to a generous splash of buttermilk in the batter."
"She whisked the buttermilk into the dry ingredients until a soft batter formed."
"Old-fashioned farmers drank fresh buttermilk straight from the churn on hot summer afternoons."
Rarely used; the plural appears mainly in technical contexts distinguishing different varieties of cultured buttermilk. In everyday usage buttermilk is an uncountable mass noun.
"The dairy offers several buttermilks, each cultured with a different bacterial strain."
Despite its name, traditional buttermilk contains little or no butter — it's literally the liquid left behind when butter is churned out of cream.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of buttermilk
The word buttermilk is a straightforward English compound of 'butter' and 'milk', attested from at least the fifteenth century. 'Butter' itself derives from Latin butyrum, borrowed from Greek boutyron, meaning roughly 'cow cheese', while 'milk' comes from Old English meolc. The compound thus names exactly what the word describes in its original sense: the milky liquid produced during butter-making. Related English terms drawing on the same Latin/Greek butter root include 'butyric' and 'butyraceous', used chiefly in chemistry.
How buttermilk is actually used
An uncountable mass noun in everyday use. Modern store-bought buttermilk is almost always the cultured variety rather than true churn leftover. In American Southern cooking it carries strong connotations of comfort food and tradition.
Easily confused with buttermilk
Whole milk is fresh, sweet, and full-fat, whereas buttermilk is tangy, thicker, and fermented (or traditionally the by-product of churning).
Sour milk is ordinary milk that has spoiled unpredictably, while buttermilk is deliberately cultured under controlled conditions and is safe for cooking.