If you're attempting to make home-baked bread but don't have any yeast (and don't want to run to the store), don't worry, you have options! The way yeast works is this: it's a fungus that reacts with water and then eats the sugar in the flour [1] of your dough to create carbon dioxide bubbles. Those bubbles create air pockets in the dough, which makes it rise. There are other easy kitchen ingredients that will have much the same effect as yeast if you don't have any actual yeast on hand, though. So don't worry, bread-lovers [2], we've spelled it all out for you in the gallery ahead.
Bicarbonate Of Soda + Lemon Juice
You can substitute bicarbonate of soda for yeast, but you also need to include an acidic substance with it. A common pairing is lemon juice, but you can also use buttermilk. The bicarbonate of soda and acid combination is a 1:1 substitute for the yeast. This means if the recipe calls for 2 teaspoons of yeast [4], you'll substitute 1 teaspoon of bicarbonate of soda and 1 teaspoon of acid. You also don't need to let the dough rise or rest like you would with a typical yeast dough.
Milk + Vinegar
If adding lemon juice to your bread dough doesn't sound appealing, you can use a mixture of milk and vinegar instead. Just combine equal parts milk, vinegar, and bicarbonate of soda to equal the amount of yeast the recipe calls for. For this one, you won't have to wait for the dough to rise before baking.
Baking Powder
Baking powder is already bicarbonate of soda and an acid, so it functions much the same way. Baking powder is the combination of bicarbonate of soda and cream of tarter, so you'll substitute it in the same 1:1 ratio as the bicarbonate of soda and acid. This means if your recipe calls for 2 teaspoons of yeast [5], you'd substitute 2 teaspoons of baking powder. This method also doesn't require resting and rising like a yeast dough.
Sourdough Starter
If you don't have yeast, making your own sourdough starter is a great option. A sourdough starter contains naturally occurring yeast, and forms bubbles in the dough to make it rise. It's made by combining flour and water, and while that sounds simple, this method actually requires a bit more patience as it takes at least five days to form. You can use one cup of sourdough starter to replace a two teaspoon yeast requirement.
Here's a breakdown of all the steps to making your own sourdough starter [6].