The Complete Guide
The Sourdough FAQ
Everything you need to know about sourdough bread — from building your first starter to baking a perfect loaf and beyond.
4–12hFermentation time
5–14 daysStarter to maturity
450–500°FBaking temperature
Contents
Getting Started
What is sourdough bread?
Sourdough is a naturally leavened bread made using wild yeast and lactic acid bacteria (LAB) that live in a fermented flour-and-water mixture called a starter (or levain). Unlike commercial yeast breads, sourdough uses no packaged yeast — the slow fermentation gives it that characteristic tangy flavor, chewy crumb, and thick crust.
What is a sourdough starter?
A starter is a live culture of wild yeast and beneficial bacteria kept alive by regularly feeding it fresh flour and water. When active, it produces carbon dioxide (which leavens the bread) and lactic/acetic acids (which create flavor). Think of it as a living ingredient you cultivate at home.
How do I create a sourdough starter from scratch?
Mix equal parts (by weight) flour and water in a clean jar — 50g whole wheat or rye flour + 50g room-temperature water is a great start. Each day, discard about half and feed with fresh flour and water. After 5–10 days you should see consistent bubbling and doubling.
Tip: Whole wheat or rye flour speeds things up because they carry more wild yeast than white flour.
How long does it take to build an active starter?
Typically 5–14 days at room temperature (70–75°F / 21–24°C). Cooler kitchens slow things down; warmer rooms speed them up. Don't get discouraged if it's slow the first few days — it usually stalls around day 2–4 before picking up steam.
What type of flour should I use?
For the starter: Whole wheat or rye flour works best initially due to higher wild yeast content. Once established, all-purpose works fine for maintenance.
For the dough: Bread flour (higher protein, 12–14%) gives better gluten structure and rise. All-purpose works too but yields a slightly denser loaf. Experiment with adding 10–20% whole wheat for extra flavor.
For the dough: Bread flour (higher protein, 12–14%) gives better gluten structure and rise. All-purpose works too but yields a slightly denser loaf. Experiment with adding 10–20% whole wheat for extra flavor.
Do I need any special equipment?
The essentials are minimal:
- Kitchen scale — sourdough is measured by weight, not volume
- Large mixing bowl — for dough development
- Dutch oven (or combo cooker) — traps steam for crust formation
- Banneton / proofing basket — shapes and supports dough during final proof
- Bench scraper — useful for shaping
- Lame or sharp razor — for scoring the dough before baking
Can I use tap water?
Yes, in most cases. If your tap water is heavily chlorinated, let it sit uncovered for 30 minutes or use filtered water — chlorine can inhibit wild yeast. Hard water (high mineral content) is actually beneficial and can improve fermentation.
Starter Care & Maintenance
How often should I feed my starter?
Room temperature: Once or twice daily. Refrigerator: Once a week is sufficient. The frequency depends on temperature and how active your starter is — a very active starter at warm temps may need feeding twice a day to avoid over-fermenting.
What is the ideal feeding ratio?
A common ratio is 1:1:1 (1 part starter : 1 part flour : 1 part water by weight). For longer fermentation between feedings, try 1:2:2 or 1:5:5 — more food means the starter takes longer to peak.
What is the "float test"? Is it reliable?
The float test involves dropping a small spoonful of starter into water — if it floats, it's ready. It works because a buoyant starter is full of CO2 gas. However, it's not perfectly reliable. Some starters that pass the float test are actually past peak. The better indicator is that your starter has doubled, is domed at the top, and smells pleasantly yeasty.
What is the liquid on top of my starter?
That gray or dark liquid is called hooch — a byproduct of alcohol fermentation that forms when the starter is hungry. It's not harmful; just stir it back in or pour it off. It means your starter needs feeding soon.
Can I store my starter in the fridge?
Absolutely — this is ideal if you bake 1–2 times a week. Cold temperatures slow fermentation dramatically so you only need to feed it once a week. To use it, take it out, feed it, let it peak at room temperature, then bake. Put leftovers back in the fridge.
My starter has pink or orange streaks — is it safe?
Discard it. Pink, orange, or red streaks indicate contamination by harmful bacteria (specifically Serratia marcescens). Start a fresh starter. This is rare but happens when utensils aren't clean or when the environment is contaminated.
Can I freeze or dry my starter for long-term storage?
Yes! Drying is the most reliable long-term method — spread a thin layer of ripe starter on parchment, let it dry completely at room temperature, then crumble into flakes and store in an airtight container for years. Freezing also works but some yeast may die off — it's better than nothing but drying is preferred.
The Dough & Fermentation
What is bulk fermentation?
Bulk fermentation (or bulk rise) is the first fermentation period after mixing your dough — before shaping. The dough ferments as one mass, developing flavor and structure. It typically lasts 4–12 hours depending on temperature and starter strength. During this time you perform stretch-and-folds to build gluten.
What is autolyse?
Autolyse is a 30–60 minute rest period after mixing just flour and water (before adding starter and salt). It allows the flour to fully hydrate and gluten to begin forming on its own — resulting in more extensible dough that's easier to work with and a better final texture.
What are stretch and folds? How do I do them?
Stretch and folds replace traditional kneading in sourdough. With wet hands, grab one side of the dough, stretch it up as high as it will go without tearing, then fold it over to the other side. Rotate the bowl 90° and repeat — that's one set (4 folds = 1 set).
Tip: Perform 3–6 sets, 20–45 minutes apart, during the first half of bulk fermentation for best gluten development.
What does hydration percentage mean?
Hydration is the ratio of water to flour by weight. 75% hydration = 750g water per 1000g flour. Higher hydration (80%+) creates a more open, chewy crumb but makes the dough much harder to handle. Beginners often do best at 70–75% before going higher.
How do I know when bulk fermentation is done?
Look for these signs:
- Dough has increased in volume by 50–75% (not necessarily doubled)
- Surface is domed and bubbly
- Jiggle the bowl — it should wobble like jello, not slosh like liquid
- Dough feels lighter and airy compared to when you started
What is cold proofing (retarding)?
After shaping, you can place your loaf in the refrigerator (covered) for 8–16 hours — sometimes up to 36 hours. This cold retard slows fermentation dramatically, developing more complex flavors and making the dough easier to score. You bake it directly from the fridge.
What is the difference between levain and starter?
Technically, your starter is the ongoing culture you maintain. A levain (or pre-ferment) is a portion of starter that you build fresh specifically for baking — often with a specific flour ratio to tune flavor. Many bakers use the terms interchangeably. A levain lets you use different flours or hydrations without altering your main starter.
Shaping & Baking
Why do I need a Dutch oven?
A Dutch oven traps steam released from the dough during the first half of baking. This steam keeps the crust soft and extensible, allowing the loaf to spring up fully before the crust sets. Without steam you get a thick, rigid crust that restricts oven spring. The lid comes off halfway through to crisp and color the crust.
What temperature should I bake sourdough at?
450–500°F (230–260°C) is ideal. Preheat the Dutch oven inside for at least 45–60 minutes. High heat creates oven spring and a deeply caramelized crust. Some bakers start at 500°F with the lid on, then drop to 450°F when removing the lid.
What is scoring and why is it important?
Scoring is making intentional cuts on the surface of the shaped dough just before baking. It controls where the bread expands — without scoring, the loaf can burst unevenly. A single curved slash at 30–45° creates the classic "ear." Use a sharp lame or razor blade for clean cuts.
How long should I bake sourdough?
A standard 900g loaf bakes for approximately 20 minutes with the lid on, then 20–25 minutes with the lid off for crust coloring. Total: ~40–45 minutes. Your loaf is done when it sounds hollow when tapped on the bottom, and the internal temperature reaches 205–210°F (96–99°C).
Can I bake sourdough without a Dutch oven?
Yes! Options include: baking on a preheated baking stone with a separate pan of boiling water on the rack below; using a covered roasting pan; or baking in a cast iron skillet topped with a large metal bowl. Results can be very good with these methods, though a Dutch oven remains the most reliable.
Why must I let sourdough cool completely before slicing?
The crumb continues to set as the loaf cools — steam and starches finish their work in the first 1–2 hours after the oven. Cutting too early releases steam prematurely, resulting in a gummy, dense crumb. Wait at least 1 hour; 2 hours is better.
Troubleshooting
Why is my bread too dense with no rise?
Most common causes:
- Starter wasn't active enough — was it at peak when you used it?
- Overproofing or underproofing — bulk went too long or not long enough
- Water too hot — killed the yeast (stay under 80°F/27°C when mixing)
- Too much salt added directly to starter — salt inhibits yeast; add it after the starter
- Weak gluten structure — not enough stretch and folds
Why is my sourdough too sour — or not sour enough?
Too sour: Longer, cooler fermentation and more whole wheat flour increases acetic acid. Reduce fermentation time or use more white flour.
Not sour enough: Shorten fermentation, use a warmer environment, bake the same day rather than cold-proofing. Acetic acid (sharp tang) develops in cool, long ferments; lactic acid (mild tang) in warm, fast ones.
Not sour enough: Shorten fermentation, use a warmer environment, bake the same day rather than cold-proofing. Acetic acid (sharp tang) develops in cool, long ferments; lactic acid (mild tang) in warm, fast ones.
Why is my crumb gummy or wet?
Gummy crumb is almost always caused by cutting the bread too soon before it's cooled. It can also result from underfermentation (dough wasn't ready) or the loaf being underbaked. Make sure internal temp hits 205–210°F and wait at least 90 minutes before slicing.
Why did my loaf spread flat instead of rising up?
This usually indicates overproofing (gluten structure has broken down) or weak shaping (insufficient surface tension). Make sure to build good tension during final shaping, and don't let the dough ferment too long at room temperature before cold proofing.
Why did my bread get a huge hole at the top?
A large tunnel or hole near the top of the crumb is typically caused by gas being trapped during shaping (poor degassing or folding technique), or from overfermentation. Make sure to gently degas during preshaping and build even tension without creating air pockets.
Why does my starter smell like nail polish remover or acetone?
This sharp, solvent-like smell means your starter is very hungry and has over-fermented. The acetic acid content is very high. It's not ruined — just feed it 2–3 times in a row with regular feedings (1:2:2 or 1:3:3) and it will come back to a pleasant, tangy-yeasty smell.
My starter isn't rising at all after 10 days — what do I do?
Try these steps:
- Move it somewhere warmer (75–80°F / 24–27°C is ideal)
- Switch to whole wheat or rye flour for a few feedings
- Add a small amount of unfiltered apple cider vinegar or pineapple juice to lower the pH and favor the right bacteria
- Make sure your container isn't too airtight
Note: Some starters take 2–3 weeks in challenging environments. Patience wins.
Storage & Shelf Life
How should I store a sourdough loaf?
For the first day, store cut-side down on a cutting board — the crust protects the crumb. After day 1, wrap in a beeswax wrap or store in a paper bag (not plastic — it softens the crust). For long-term: slice and freeze in an airtight bag. Frozen sourdough toasts beautifully directly from frozen.
How long does sourdough bread last?
Because of its natural acidity, sourdough lasts 4–5 days at room temperature — longer than commercial yeast bread. The acetic acid acts as a natural preservative. A whole, uncut loaf lasts longer than a cut one. After 5 days, it's best toasted or used for croutons.
Can I freeze sourdough bread?
Yes — sourdough freezes excellently. Slice the entire loaf before freezing and store in a zip-lock or airtight bag with the air squeezed out. Individual slices can be toasted directly from frozen. A whole loaf can be wrapped tightly in foil and frozen for up to 3 months, then reheated in a 350°F oven for 15–20 minutes.
Should I refrigerate sourdough bread?
No. Refrigerating bread actually speeds up staling — a process called retrogradation. The cold causes starch molecules to recrystallize faster, making bread dry and crumbly quicker than room temperature storage. Stick to room temp or the freezer.
Nutrition & Health
Is sourdough healthier than regular bread?
There are some genuine nutritional advantages. The long fermentation process partially breaks down phytic acid (an anti-nutrient in grains), increasing mineral bioavailability. The lower pH (from lactic acid) lowers the glycemic index compared to commercial bread. Some people with gluten sensitivity (not celiac) find sourdough easier to digest.
Can people with gluten intolerance eat sourdough?
People with celiac disease should not eat wheat sourdough — it still contains gluten.
However, people with non-celiac gluten sensitivity may find that long-fermented sourdough is more tolerable. This is because some gluten proteins are partially broken down during fermentation. Always consult a doctor or dietitian if you have a diagnosed condition.
Does sourdough contain probiotics?
The bacteria that ferment sourdough are killed during baking, so the finished bread does not contain live probiotic cultures. However, sourdough does contain prebiotic fibers and organic acids that support gut health — and the fermentation makes nutrients more accessible than in unfermented bread.
Is sourdough lower in calories than regular bread?
Not significantly. The calorie content per gram of flour is roughly the same. However, sourdough's lower glycemic index means blood sugar rises more slowly after eating it, which can have benefits for energy stability and satiety. The density of artisan sourdough also means you may naturally eat smaller quantities than supermarket sandwich bread.
Can I make sourdough with gluten-free flour?
Yes, though the process is quite different. Gluten-free sourdough uses flours like brown rice, buckwheat, sorghum, or teff. Without gluten, the dough behaves more like a thick batter and won't develop the same chewy structure. Xanthan gum or psyllium husk is often added as a binder. Results can be very good but require separate recipes designed for GF flours.