Baking Powder (Best Option)
3 teaspoons per 1 teaspoon of baking sodaBaking powder contains both an acid and a base, allowing it to release carbon dioxide gas upon hydration and heat, which mimics the leavening action of baking soda in focaccia dough. It compensates for the lack of acidic ingredients in the dough by providing its own acid-base reaction.
To ensure success, use slightly more baking powder than baking soda (about three times the amount) because baking powder is less concentrated. Be careful not to overdo it, as too much can cause a bitter taste and excessive rise leading to collapse.
The final focaccia will have a similar rise and texture, though the crumb may be a bit lighter and less chewy. The flavor remains close to the original, making it the best chemical leavening substitute.