How to Make a Sourdough Starter From Scratch: A 7 Day Guide for Beginners
Learning how to make a sourdough starter takes two ingredients, a jar, and about seven days of feeds that each take a minute or two. This easy sourdough starter from scratch uses only bread flour and water. The wild yeast already living in the flour does the work, with no commercial yeast involved.
Disclosure: This post may contain affiliate links. This means I get a small commission if you decide to make a purchase through my links at no extra cost to you.
You mix equal weights of flour and water on day one, then discard part of it and feed it every day, moving to twice a day from day four. Two things decide how fast it gets there: a warm spot around 75°F, and bread flour, whose higher protein gives the culture more to work with. You will have discard from day two, and that early discard is perfect for long-fermented sourdough granola, where the starter binds and flavors rather than lifts.
Jump to:
Why This Method Works
- A wild yeast sourdough starter needs nothing but flour, water, and time. It lives on the flour and in the air of your kitchen. You are not adding yeast; you are giving what already exists something to eat and somewhere warm to sit. Most of what makes this sound complicated is folklore, and a fair amount of it is covered in these sourdough myths worth ignoring.
- Two ingredients, nothing to buy. Flour, water, a jar, a kitchen scale, and a rubber band. The rest of the usual bread baking tools can wait until you are baking loaves.
- The discard is the engine, not the waste. Each feed adds a fixed amount of food. Discarding before every feed keeps the ratio of fresh flour to culture high, which builds a strong starter instead of a large, weak one, and keeps the jar from overflowing.
- Weights, not cups. Flour compacts in a measuring cup, and a starter built on inconsistent ratios behaves inconsistently.
- It fits around a family schedule. Days one to three need thirty seconds of attention. The twice-daily stretch from day four is two minutes, morning and evening, which is what makes this an easy sourdough starter to keep up with.
Sourdough Starter Ingredients and the Best Flour to Use
- Bread flour. Bread flour is the best flour for sourdough starter. A sourdough starter with bread flour has more gluten structure to hold gas as it rises, so it doubles sooner and more reliably. Use unbleached. Bleached flour slows fermentation, and self-rising flour already contains leavening you do not want. Whole wheat flour works too and ferments a little faster, with a darker, slightly thicker starter.
- Filtered water. Chlorinated tap water can slow a homemade sourdough starter down. Filtered or bottled water is safest. If neither is available, boil tap water and let it cool completely first.
How to Make a Sourdough Starter: The 7-Day Timeline
These simple sourdough starter instructions go step by step through each stage of a sourdough starter, with what the jar should look like at every point.
Day 1: Mix. To start a sourdough starter, weigh 100 grams of bread flour and 100 grams of filtered water into a clear, wide-mouth glass jar with room for the starter to double. Stir until no dry flour remains, rest the lid on top without sealing it, and leave the jar somewhere warm for 24 hours. Nothing happens on day one or day two. Thick, flat, and still is exactly right at this stage.
Days 2 and 3: discard, feed, and watch for bubbles. Each day, remove and throw away 100 grams, then feed 50 grams of flour and 50 grams of water and stir well. Save that discard in a jar in the fridge; these 3 ingredient sourdough discard crackers use it with no added flour. By day 3, bubbles show through the lower part of the jar and the starter lifts a little after each feed. From this feed on, slide a rubber band around the jar at the level of the starter right after feeding, so you can see the rise instead of guessing at it.
By about day 3, my starter had a surprisingly strong smell. It wasn't the pleasant sourdough aroma I expected yet. It was sharper and a little funky. That stage can be completely normal, and after a few more feedings, the smell became much cleaner, pleasantly tangy, and slightly yeasty.
Days 4 and 5: feed twice a day. Same feed, morning and evening, 10-12 hours apart. The starter now rises clearly above the band after every feed, taller and faster each time. By the evening of day 4, you may find a layer of dark liquid on top. That sourdough starter hooch means the culture is active and hungry, not spoiled. Stir it back in for a tangier starter or pour it off for a milder one, then feed as usual.
Days 6 and 7: keep going until it doubles. Keep feeding twice a day. By day 7, most starters are domed and well past double a few hours after a feed, with bubbles all the way through the jar. If yours is close but not there, keep feeding. Ten days is normal in a cool kitchen, and fourteen is not unusual.
My kitchen temperature made a noticeable difference to how quickly my starter developed. On warmer days it became active much sooner, while cooler weather slowed everything down by a day or two. After making several starters, I stopped watching the calendar and started watching the bubbles and rise instead.
How to Tell Your Sourdough Starter Is Ready
This sourdough starter recipe is done when it passes three checks, in order of reliability:
- It doubles on a schedule. With the rubber band marking the level after each feed, a ready sourdough starter reaches double within 6-8 hours, consistently, not just once.
- It is bubbly all the way through. Not just foam on top. Look through the side of the jar for holes running through the whole body of the starter.
- It floats. Drop a teaspoon of starter into a glass of water. If it floats, an active sourdough starter holds enough gas to raise dough. The float test is a useful confirmation but a poor sole judge, since a starter can fail it and still bake well. Trust the doubling first.
The first thing I baked with my starter was a simple sourdough sandwich loaf rather than an artisan boule. It gave me a chance to learn how my starter behaved without worrying about perfect oven spring or an open crumb. The loaf turned out soft and flavorful and gave me the confidence to keep baking with the same starter. If you would rather skip the overnight cold proof for your first bake, this same-day sourdough bread is mixed in the morning and sliced the same evening.
Sourdough Starter FAQs
Yes, and it will work. All-purpose flour has less protein than bread flour, so expect a slightly looser starter and often an extra day or two before it doubles reliably. A sourdough starter with bread flour gets there sooner. The day-by-day timings in this sourdough starter recipe are for bread flour.
Sourdough starter mold shows up as fuzzy growth, black spots, or a pink or orange tinge, and it means throw it out and start again. Wash the jar thoroughly and consider a different bag of flour. Sourdough starter hooch and a gray liquid layer are not mold. Sealing the jar airtight is one of the common mistakes beginners make with sourdough, and it makes mold more likely, so keep the lid resting loosely.
For most people learning how to make a sourdough starter, seven days is typical with bread flour in a warm kitchen, and 10-14 days is common in cooler homes. The calendar matters less than the behavior: when the starter doubles reliably within 6-8 hours of a feed, it is ready, whatever day that lands on.
Before day seven, a slow starter is usually normal, and the answer is warmth plus time. Past day ten, move it somewhere warmer and keep the feeds consistent, and if it is still flat, the fix is a feeding change rather than more waiting. The sourdough starter feeding and maintenance guide covers how to strengthen a weak starter.
What to Do Next
Once you know how to make a sourdough starter from scratch, the next job is a routine that keeps your homemade bread starter alive through a normal week, and the guide to feeding and maintaining a sourdough starter covers ratios, fridge storage, and fixes. When your starter is doubling reliably, put it to work in a lemon blueberry sourdough bread with fresh berries folded straight into the dough, then work through these sourdough bread variations.
Made this sourdough starter? Leave a comment and tell me what day yours started doubling!
Equipment
- Wide-mouth glass jar 32 oz
Ingredients
- 500 g bread flour unbleached
- 500 g filtered water
Instructions
Day 1
- Weigh 100 g of bread flour and 100 g of filtered water into a clean, wide-mouth glass jar. Stir until no dry flour remains.
- Rest the lid loosely on top without sealing it. Leave the jar somewhere warm (about 75°F) for 24 hours.
Days 2 and 3
- Remove and discard 100 g of starter. Add 50 g of flour and 50 g of water, and stir well.
- Leave in the warm spot for 24 hours. On day 3, slide a rubber band around the jar at the level of the starter right after feeding.
Days 4 to 7
- Feed twice a day, 10-12 hours apart: discard 100 g, then add 50 g flour and 50 g water and stir. Move the rubber band to the new level after each feed.
Check readiness
- The starter is ready when it is bubbly throughout and doubles within 6-8 hours of a feed. If it is not there by day 7, keep feeding twice a day for up to 7 more days.
Notes
- The flour and water totals cover all seven days. Most of it is discarded along the way.
- Keep the starter around 75°F. An oven with the light on, the top of the fridge, or a spot near a heating vent all work.
- Use filtered or bottled water. If neither is available, boil tap water and cool it completely.
- Ready means doubling within 6-8 hours of a feed, not a date on the calendar. A cool kitchen can add a week.
- Dark liquid on top (hooch) means the starter is hungry. Fuzzy growth or a pink or orange color means start over.
- Store discard in a separate jar in the fridge for crackers, pancakes, or granola.