Brussels waffles are traditionally leavened with what type of yeast?

Brussels waffles were traditionally leavened with ale yeast.

Ale yeast refers to the brewer’s yeast traditionally used in the yeast-raised batter associated with Brussels waffles. The yeast gives the batter time to ferment and rise, helping produce the style’s characteristic light texture, crisp exterior, and large open pockets. Some Brussels waffle recipes instead use whipped egg whites, and some combine egg-white and yeast leavening.

Brussels waffles are rectangular and generally lighter and airier than Liège waffles. They are traditionally served warm, often dusted with confectioners’ sugar. In tourist settings, whipped cream, fruit, chocolate spread, or other toppings may be added, but these do not define the original leavening method.

The named Brussels style was formalized in the nineteenth century. Florian Dacher is associated with a Brussels waffle recipe recorded in 1842–43, while later vendors helped popularize related Belgian waffles internationally. A common confusion is “Belgian waffle,” an English-language category that often uses baking powder today; that modern usage does not erase the older ale-yeast tradition of Brussels waffles.