Ammonium bicarbonate was used in the food industry as a raising agent (e.g., for gingerbreador Chinese youtiao before the introduction of baking soda Ammonium bicarbonate is still used in many food products, in addition to baking soda. Many baking cookbooks (especially from Scandinavian countries) may still refer to it as hartshorn or hornsalt ^. It is fine to replace it with baking soda.