sachet levure chimique

Levure chimique (chemical yeast) is a leavening agent composed primarily of baking soda (sodium bicarbonate) combined with one or more acids and a neutral filler, typically cornstarch or potato starch. The term "sachet" refers to the pre-measured envelope or packet containing a standardized dose of the leavening mixture, commonly used in French home baking. When mixed with moist ingredients, the acid and base react to produce carbon dioxide gas, which creates lift and volume in baked goods without requiring fermentation or proofing time.

The typical composition consists of approximately 50% baking soda and 50% acid salts (such as cream of tartar or sodium aluminum sulfate) plus starch as an anti-caking agent. This formulation mimics single-acting baking powder, producing gas during mixing and initial baking, resulting in immediate leavening action.

Levure chimique is used extensively in French and European baking to leaven cakes, pastries, quick breads, and crêpes. The pre-portioned sachets simplify home baking by eliminating the need to measure individual leavening components; one sachet typically leavens 250g of flour. It is particularly valued in cake batters, pancake preparations (pâte à crêpes), and applications requiring fast, reliable rise without fermentation. The ingredient performs similarly to commercial baking powder and is often directly substituted for it in recipes.