Clabbers

Clabbers is a colloquial term for milk that has soured and thickened, typically due to bacterial action. This natural process causes the milk proteins, primarily casein, to coagulate and form a gel-like substance. The souring is a result of lactic acid bacteria converting lactose, the sugar in milk, into lactic acid. This increase in acidity lowers the pH of the milk, causing the proteins to denature and clump together.

The term "clabbered milk" is often used interchangeably with "soured milk," though clabbered milk specifically refers to the thickened state. Historically, clabber was a common way to preserve milk before refrigeration was widely available, as the acidic environment inhibits the growth of spoilage bacteria. It was also a versatile ingredient in cooking and baking, particularly in traditional recipes for bread, cakes, and pastries, where its acidity could react with baking soda to provide leavening. While less common in modern Western diets, clabbered milk or similar fermented dairy products are still consumed in various cultures around the world. The texture can range from a soft, custard-like consistency to a firmer curd, depending on the extent of fermentation and the type of milk used.