jäsa

Jäsa is a Swedish verb meaning to ferment or to cause a mixture, such as dough or liquid, to ferment and rise. It is commonly used in baking and brewing to describe the fermentation process driven by yeast or lactic acid bacteria. In everyday baking, jäsa refers to the dough’s expansion as bubbles form and the dough becomes lighter.

In baking contexts, jäsa typically follows kneading and precedes baking. Phrases like låt degen jäsa (let the dough rise) are common. The related noun jäst refers to yeast, while jäsning denotes fermentation or the rising process. The dough’s temperature and the presence of yeast or other leavening agents influence how quickly jäse occurs and how much the dough rises.

Grammatically, jäsa is conjugated as follows in the present tense: jag jäser, du jäser, han/hon/den jäser, vi ni de jäser. The past tense is jäste, and the supine (used with have/had) is jäst. Note that jäst also exists as the noun for yeast, which can be a source of ambiguity in text.

Outside baking, jäsa is also used for fermentation processes in brewing, winemaking, and other culinary applications, where yeasts metabolize sugars to produce alcohol and carbon dioxide. Proper jäst handling, temperature control, and cleanliness are important factors affecting the rate and outcome of fermentation.

See also: fermentation, yeast (jäst), bread making.