Gear guide
Best flour for sourdough
The flour is the dough the math is written for. Get the protein right and a slack 75% dough holds together and springs; get it wrong and the prettiest formula still bakes flat. One number decides most of it.
The short answer: The best flour for sourdough is an unbleached white bread flour around 12–13% protein — enough gluten to hold the hydration and trap the gas. Want more open crumb? Go 13–14% artisan. Want flavor? Blend in 10–30% whole wheat. Protein is the number that matters; the brand just needs to be consistent.
Compare the workhorse bread-flour pick on Amazon →As an Amazon Associate, SourdoughHydration earns from qualifying purchases at no extra cost to you.
What actually matters
- 1. Protein (the one number)
Bread flour ~12–14% vs all-purpose ~10–11%. Protein builds the gluten that holds high hydration and traps gas. This decides more than the brand on the bag.
- 2. Bread vs all-purpose
Use bread flour. All-purpose bakes a denser, flatter loaf — especially as hydration climbs. The whole site's math assumes real bread flour.
- 3. White vs whole grain
Mostly white for structure; blend 10–30% whole wheat or rye for flavor + a livelier ferment. 100% whole grain is denser and thirstier — great later, hard as a first loaf.
- 4. Consistency over prestige
A consistent brand = repeatable loaves. Unbleached beats bleached for dough. Organic/specialty is about sourcing, not a better crumb at the same protein.
What to skip: bleached flour (it can weaken dough), self-rising flour (it has added leavening + salt — wrong for sourdough), and chasing exotic specialty flours before a plain bread flour bakes you a consistent loaf. Nail the protein first; experiment with the fancy stuff later.
Protein by bag, as the mill states it
| Flour | Protein |
|---|
| King Arthur Unbleached Bread Flour | 12.7% |
| King Arthur Unbleached All-Purpose Flour | 11.7% |
| King Arthur High-Gluten Flour | 14.2% |
| King Arthur Whole Wheat Flour | 13.2% |
| Bob's Red Mill Artisan Bread Flour | 12–14% |
Sources: King Arthur Baking, “Protein percentage in flour”; Bob's Red Mill, Artisan Bread Flour. Whole wheat reads high on protein but its bran cuts gluten, so it still needs the extra water this site's math adds.
The picks, by what you want
- Best overall · the defaultWorkhorse white bread flour (~12–13% protein)
A consistent, unbleached white bread flour in the ~12–13% protein range is the dough every recipe on this site is written for. It absorbs the hydration you calculate and builds the gluten that traps the gas — King Arthur Bread Flour (~12.7%) is the widely-available US benchmark, and brand consistency means a loaf you can repeat, not one you got lucky with.
Watch out: Check it says 'bread flour', not 'all-purpose' — and unbleached. All-purpose (~10–11%) can't hold a high-hydration dough.
Compare on Amazon → - Best for open crumb & high hydrationHigh-protein artisan / professional bread flour
Step up to a professional-grade high-protein artisan flour (the kind small bakeries use) when you push hydration higher or want a more open, chewy crumb. The extra gluten strength holds more water and a longer fermentation without the dough going slack.
Watch out: Higher protein wants more water and more dough strength — adjust hydration up gradually rather than all at once.
Compare on Amazon → - Best for flavor & a faster, livelier fermentWhole-wheat / whole-grain bread flour
Whole grain brings flavor, more nutrition, and wild-yeast food that wakes up a starter — most bakers blend 10–30% into white flour rather than going 100%. Stone-ground whole wheat is the classic choice for that nutty, tangy country loaf.
Watch out: Whole grain drinks more water and ferments faster — raise hydration and shorten the bulk a touch, or the loaf turns dense and gummy.
Compare on Amazon → - Best if you care about sourcingOrganic / regeneratively-milled flour
If sourcing matters to you, certified-organic unbleached bread flour bakes identically to conventional at the same protein level — you're paying for the farming and milling story, not a different loaf. A fine choice; just match the protein tier above.
Compare on Amazon →
As an Amazon Associate, SourdoughHydration earns from qualifying purchases at no extra cost to you. More on how this is funded.
Compare flour types in depth — protein, absorption & hydration by flour →
🎧 The flour is half the storyKnowing how a flour behaves — why protein, why whole grain ferments faster — is what turns a bag of flour into a great loaf. Maurizio Leo’s The Perfect Loaf and Ken Forkish’s Flour Water Salt Yeast are on Audible, and a free trial gets you one to listen to while your dough proofs.
Start a free Audible trial →
Common questions
What flour is best for sourdough?
An unbleached white bread flour in roughly the 12–13% protein range is the best all-round choice — it has the gluten strength to hold the high hydration sourdough needs and to trap the gas for a good rise. Many bakers then blend in 10–30% whole wheat or rye for flavor. All-purpose flour can work for a simpler loaf but bakes flatter; the protein is the number that matters most.
Bread flour or all-purpose for sourdough?
Bread flour. The difference is protein: bread flour sits around 12–14%, all-purpose around 10–11%. That extra protein builds the gluten network that holds a slack, high-hydration sourdough together and traps the carbon dioxide for oven spring. You can bake sourdough with all-purpose, but you'll get a denser, flatter loaf — especially at higher hydration.
What protein percentage should sourdough flour have?
Aim for about 12–14% for white bread flour. Around 12–13% (e.g. King Arthur Bread Flour at ~12.7%) is a forgiving, versatile target; higher-protein artisan flours (13–14%) hold even more water and give a more open, chewy crumb but want a stronger hand. Below ~11% (all-purpose) the dough struggles to hold hydration.
Should I use whole wheat or white flour for sourdough?
Most bakers use mostly white bread flour with a whole-grain blend — typically 10–30% whole wheat or rye — for the best of both: structure from the white, plus flavor, nutrition, and a livelier ferment from the whole grain. A 100% whole-wheat loaf is denser and needs more water and a shorter bulk; great once you've got the technique, harder as a first loaf.
Is organic or expensive flour worth it for sourdough?
For the loaf itself, no — what matters is protein and freshness, and a good conventional bread flour at the right protein bakes just as well. Organic or specialty-milled flours are worth it if you value the sourcing and farming, not because they produce a better crumb at the same protein level. Spend on consistency and the right protein first.
The rest of the bake-day kit
Got the flour? Weigh it, shape it, bake it.