How to Build a Sourdough Starter from Scratch

Steps

1. 1Day 1: Ideally, you are using a straight-sided vessel for this project; otherwise, a large bowl is fine. (Note: A straight-sided vessel allows you to truly see how much your starter is growing. I’m using this Cambro.) Stir together the flour and water (or juice) until the flour is absorbed. Cover the vessel. Record the date, time, and measurements — you will forget which day you started if you don’t. Let it sit in a cozy environment — 75ºF to 80ºF is ideal (see ideas above) — for 24 hours. If you remember, stir the starter once or twice over these 24 hours.
2. 2Day 2: Uncover the vessel. Stir the mixture. Re-cover the vessel, and record your work. Let it sit in a cozy environment for another 24 hours. If you remember, stir the starter once or twice over these 24 hours.
3. 3Day 3: Uncover the vessel. Add 128 grams (1 cup) of flour and 128 grams (about 1/2 cup) of water. Stir to combine. Cover the vessel, mark the height of your mixture with tape, and record your work again. Place it in a cozy spot. If possible, monitor your starter over the next 8 to 10 hours and if… …your starter doubles or begins to double, feed it with 128 grams each flour and water. If it doubles again before it’s time for you to go to bed, skip to Day 5 and proceed with making the offshoot. If it doesn’t, let it in a cozy environment overnight. Then proceed with making the offshoot (step 5) in the morning.
4. 4… you are not seeing much action, continue to let it sit in a cozy environment till the following day, stirring it once or twice. Proceed with Day 4 in the morning.
5. 5Day 4: Uncover the vessel. You should see some action (bubbles), and your starter should smell pleasant, not unlike a fruity yogurt. Stir it, then feed it with 128 grams each flour and water. Stir to combine. Cover the vessel, mark the height of your mixture with tape, and record your work again. Place it in a cozy spot. If possible, monitor your starter over the next 8 to 10 hours and if… …your starter doubles or begins to double, drop a spoonful of it in water. If it floats, you’re in business. Skip to Day 5 and proceed with making the offshoot.
6. 6… your starter is not quite doubling, continue to let it sit in a cozy environment till the following day, stirring it once or twice. Proceed with Day 5 in the morning.
7. 7Day 5: At this point, you should be observing some activity in your starter, meaning the starter should have risen slightly (perhaps doubled but perhaps not) and fallen with bubbles transforming from big to small. You’ll now take a small portion of this mixture and build a new starter: Transfer 100 grams of the starter to a new jar or vessel, and add 100 grams of flour and 100 grams of water. Stir well to combine, then cover the jar. Mark the height with a rubber band. Let it sit in a cozy spot. Transfer the remaining starter to the fridge — this original mixture is now your sourdough discard and can be used in all sorts of recipes, see notes above. When your new starter doubles in volume, you can do one of three things: Repeat this process: spoon 100 grams of starter into a new vessel and add 100 grams each of flour and water. (Transfer the remaining starter to your bucket of discard.) Let the new starter rise in a cozy spot until it doubles. Your starter will get stronger with every feeding.
8. 8Transfer it to the fridge if you need to take a break from the process. You can pick up where you left off when you are ready.
9. 9Test it out in a sourdough bread recipe.
10. 10"instruction-step-10">
11. 11Maintaining your starter: Once you have a strong, active starter on your hands, follow the steps in this post: How to Feed, Store, and Maintain a Sourdough Starter.