Lemon Juice (Best Option)
1 tablespoon lemon juice per 1 tablespoon white vinegarLemon juice contains citric acid, which reacts with baking soda in brownies to produce carbon dioxide, helping the batter rise and develop a tender crumb. This acid-base reaction is critical for texture and lift. When substituting, use an equal volume to maintain the proper acidity balance.
To ensure success, use fresh lemon juice for the best acidity and flavor. Avoid excessive amounts as it can impart a noticeable citrus tang. Incorporate it evenly into the wet ingredients to promote uniform leavening.
Compared to white vinegar, lemon juice offers a slightly brighter flavor but does not detract from the chocolate richness. The texture remains moist and tender, making it an excellent alternative in brownies.