Sourdough bread is a type of bread that is made with natural yeast that is cultivated from flour and water. This natural yeast is called a sourdough starter, and it gives sourdough bread its distinctive tangy flavor and chewy texture. To make sourdough bread from scratch without using commercial yeast, you need to make your own sourdough starter and feed it regularly until it is active and bubbly. This can take anywhere from a few days to a few weeks, depending on the temperature, humidity, and type of flour you use. To make your own sourdough starter, follow these steps: - In a large glass jar or bowl, mix one cup of all-purpose flour and one cup of water until well combined. Cover loosely with a lid or a cloth and let it sit at room temperature for 24 hours. - The next day, discard half of the mixture and add another half cup of flour and half cup of water. - Stir well and cover loosely again. - Repeat this process every day until you see bubbles forming on the surface of the mixture and smell a sour or fruity aroma. This means your starter is ready to use or store in the refrigerator until needed. To make sourdough bread from scratch, follow these steps: - In a large bowl, mix one cup of active sourdough starter with one and a half cups of warm water. - Add four cups of bread flour, two teaspoons of salt, and any other ingredients you like, such as seeds, nuts, dried fruits, herbs, etc. Mix well with a wooden spoon or your hands until a shaggy dough forms. - Turn the dough out onto a lightly floured surface and knead it for about 15 minutes, adding more flour as needed to prevent sticking. The dough should be smooth and elastic. - Place the dough in a lightly greased bowl and cover with plastic wrap or a damp cloth. Let it rise at room temperature for about 4 hours, or until doubled in size. - Punch down the dough and shape it into a round loaf. - Place it on a parchment-lined baking sheet or in a lightly greased cast-iron skillet or Dutch oven. Cover with plastic wrap or a damp cloth and let it rise again for about 2 hours, or until puffy. - Preheat your oven to 450°F and place an empty metal pan on the bottom rack. Slash the top of your loaf with a sharp knife or razor blade to create steam vents. - Carefully transfer your loaf to the oven and pour one cup of hot water into the metal pan to create steam. - Bake your loaf for about 30 minutes, or until golden brown and hollow sounding when tapped. Let it cool completely on a wire rack before slicing and enjoying.