f: 1 3/4 tsp potash. edit: research tells me you can substitute potash for baking powder

Potash is a form of potassium carbonate (K₂CO₃), a white crystalline salt historically derived from wood ash through leaching and evaporation. In culinary contexts, potash refers specifically to potassium carbonate or sometimes potassium bicarbonate used as a leavening and pH-altering agent. It appears in various food traditions, particularly in Middle Eastern, North African, and Asian cuisines, where it was among the earliest chemical leavening agents available before the widespread adoption of baking powder and baking soda in modern times. Potash produces carbon dioxide gas when combined with acidic ingredients or moisture, creating lift in baked goods and doughs.

Potash has a distinctly bitter, soapy taste and should be used judiciously. Its alkaline nature not only promotes browning through the Maillard reaction but also affects gluten development and can enhance certain flavors in traditional preparations like pretzels and some flatbreads.

Potash functions as a leavening agent in traditional baking, particularly in recipes predating commercial baking powder. It is essential in the preparation of certain regional breads and pastries, such as Middle Eastern maamoul (filled cookies) and some rustic flatbreads. When combined with an acid (vinegar, lemon juice, or acidic spices), potash releases carbon dioxide, creating airiness and lift. It is also used in small quantities to adjust pH in fermented foods and to enhance browning in baked goods. In modern baking, potash has largely been superseded by baking soda and baking powder, though some traditional recipes and artisanal bakers continue to use it for authentic flavor and texture development.