Step 1

Measure 100 grams flour and 100 grams water into a jar with a tight-fitting lid, and then whisk them together using a fork. If using an established sourdough starter, whisk it into the flour and water now. Set the jar on the countertop away from direct light and heat.

Step 2

Set a bowl on your kitchen scale, and then tare the scale. Measure 100 grams sourdough starter into the bowl, and then discard it.

Step 3

Set the jar containing your starter onto the scale, tare it again, and then measure in 50 grams water. Whisk the water into the starter in your jar, and then whisk in 50 grams flour. Clamp the jar tightly, and then set it on your countertop away from direct light and heat.

Step 4

You should begin seeing bubbles appear on the surface of your starter, or the surface may appear slightly foamy. These are signs of microbial activity.

Step 5

Measure 100 grams sourdough starter into the bowl, and then discard it.

Step 6

After discarding the starter, whisk in 50 grams warm water and 50 grams flour. Seal the jar and store it away from direct light and heat.

Step 7

The surface of your starter should appear slightly bubbly, and you may see evidence that your starter is beginning to expand in the jar. You should start feeding your starter twice a day today.

Step 8

In the morning, measure 100 grams sourdough starter and discard it.

Step 9

After discarding the starter, whisk in 50 grams water and 50 grams flour. Seal the jar and store it away from direct light and heat.

Step 10

In the evening about 12 hours after your first feeding, discard 100 grams starter, and then whisk in 50 grams water and 50 grams flour. Seal the jar tightly, and store it away from light and heat.

Step 11

The surface of your starter should be very bubbly, and it may expel gas when you open the jar. You should also see evidence that your starter is expanding in its jar.

Step 12

In the morning, measure 100 grams sourdough starter and discard it. Whisk in 50 grams water and 50 grams flour, and store the jar away from direct light and heat.

Step 13

In the evening about 12 hours after your first feeding, feed the starter again by discarding 100 grams starter and replacing it with 50 grams water and 50 grams flour.

Step 14

Your starter should be bubbly, and it should smell of yeast and bread with faint sour notes. It should also double within 12 hours of each feeding.

Step 15

Discard 100 grams of starter, and then whisk in 50 grams water and 50 grams flour.

Step 16

If you're planning to bake with the starter today, wait until it doubles in volume and then follow your recipe's instructions. If you're planning to bake with the starter later, transfer it to the fridge.

Step 17

To maintain the starter, remove it from the fridge at least once per week. Discard 100 grams starter, and then whisk in 50 grams water and 50 grams flour. Let it rise at room temperature up to 12 hours if you're planning to bake that day. If you're planning to bake later, transfer it to the fridge.

Step 18

Remove the starter from the fridge approximately 8 to 12 hours before you plan to begin your recipe.

Step 19

Feed the starter by discarding 100 grams spent starter, and replacing it by whisking 50 grams flour and 50 grams into the jar. Seal the jar, and let it sit on the countertop until it doubles in volume.

Step 20

Remove the amount of starter that your recipe calls for, and then replace it with equal amounts of flour and water. Transfer the jar of starter to the fridge.