soured

Soured is the past participle of sour and an adjective used to describe foods, beverages, or conditions that have developed acidity or tang, typically through fermentation or spoilage. The term is common in culinary contexts as well as in everyday language to indicate a change from a previously neutral or pleasant state to one characterized by acidity.

In food and drink, soured quality often results from lactic acid bacteria converting sugars into lactic acid. Soured milk, for example, refers to milk that has undergone fermentation or spoilage, producing a tangy flavor and thicker texture. Some dairy products, such as yogurt or cultured buttermilk, intentionally harness this fermentation to create desirable sour notes and textures. Fermentation is also central to sourdough, where dough is leavened by wild yeasts and lactic acid bacteria, giving a characteristic tang as part of the flavor profile.

Souring is also a deliberate technique in beverages. Sour beers, including styles like Lambic and Gueuze, rely on lactic acid bacteria to generate acidity and complexity. In wine and other fermented drinks, unwanted souring can indicate spoilage or infection, altering flavor and quality in undesirable ways.

In non-culinary usage, soured can describe a change in mood, relations, or circumstances from favorable to unfavorable. For example, a partnership or agreement can soured if trust or cooperation deteriorates.

Overall, soured denotes a shift toward acidity or tang, whether through natural fermentation, intentional production, spoilage, or metaphorical decline.