Bread Flour vs All-Purpose Flour for Sourdough (Plus UK & Australian Names)
The same flours go by different names in the US, UK and Australia. Here's what to buy for sourdough, how to read the protein figure on the label, and how to adjust hydration.
Why protein matters
When flour is mixed with water, its proteins form gluten, the stretchy network that traps gas. Higher-protein flour generally makes a stronger dough that holds more water and keeps its shape better. That's why many sourdough recipes call for bread flour, especially at higher hydrations.
Flour names by country
| Type | US | UK | Australia | Typical protein |
|---|---|---|---|---|
| High-protein white | Bread flour | Strong white bread flour | Baker's flour / bread flour | ~12–14% |
| Extra high-protein | High-gluten flour | Very strong / extra strong white | Some "strong" baker's flours | ~14%+ |
| General purpose | All-purpose flour | Plain flour | Plain flour | ~9–12% |
| Whole grain | Whole wheat flour | Wholemeal flour | Wholemeal flour | varies |
| With raising agent | Self-rising flour | Self-raising flour | Self-raising flour | n/a |
Ranges are approximate and brands differ, sometimes a lot. The label on your bag is the best guide. Self-rising and self-raising flours contain baking powder (US self-rising also contains salt), so they aren't used for sourdough bread.
How to read the protein on the label
- UK and Australia: nutrition panels list protein per 100 g, so the number is the percentage. "Protein 12.5 g per 100 g" means 12.5%.
- US: the Nutrition Facts panel lists protein per serving (often 30 g, about ¼ cup), rounded to the nearest gram. "4 g per 30 g" works out to roughly 13%, but because of rounding the true figure could be anywhere from about 11.7% to 15%. Many US mills publish an exact protein percentage on their websites.
Can you make sourdough with all-purpose or plain flour?
Yes. Plenty of good loaves are made with all-purpose or plain flour. Expect a few differences:
- It absorbs less water. If a recipe was written for bread flour, try lowering the hydration by roughly 2–5 percentage points (for example, 75% down to 70–72%) and add more only if the dough feels stiff.
- The dough is weaker. It spreads more, so extra folds and a well-tensioned shape help.
- The crumb is often softer and less chewy, which many people like for sandwich loaves.
Going the other way (an all-purpose recipe made with bread flour), the dough may feel tighter, and you can usually add a little more water.
Mixing flours
Blending is common: for example 80% bread flour with 20% whole wheat. In baker's percentages, all flours together make 100%, so an 80/20 blend with 500 g total is 400 g white plus 100 g whole wheat. Whole grain flour drinks more water; see whole wheat sourdough hydration for starting ranges.
Quick buying guide
- US: bread flour for open, chewy loaves; all-purpose for softer loaves or a lower-hydration starting point.
- UK: "strong white bread flour" for most sourdough. Plain flour is the all-purpose equivalent.
- Australia: look for "baker's flour" or "bread flour" and check the protein per 100 g. Plain flour is the all-purpose equivalent.
Whichever you use, weigh it. Our grams to ounces chart covers conversions, and the 80% hydration guide explains why strong flour helps with wetter doughs.
Whatever flour you use, the calculator works out exact weights from your chosen hydration and starter percentage.
Open the free calculatorFAQ
Is strong white flour the same as bread flour?
Broadly, yes. Strong white bread flour is the usual UK name for high-protein white flour, the equivalent of US bread flour. Exact protein varies by brand.
What is baker's flour in Australia?
It's the common Australian name for higher-protein white bread flour. Check the nutrition panel: the protein figure per 100 g is the protein percentage.
Can I use all-purpose or plain flour for sourdough?
Yes. It usually absorbs less water than bread flour, so start a few percentage points lower on hydration and build strength with folds.
Can I use self-raising flour for sourdough?
It isn't recommended. Self-raising (self-rising) flour contains baking powder, and in the US also salt, which changes the dough and the salt maths.