All Purpose vs Bread Flour in Sourdough

Can You Switch and Still Get a Great Loaf?

I’ve always fed my starter with AP flour but baked my loaves with bread flour. Recently I seriously considered switching everything to organic AP. Why?

• Cost
• Availability at Costco
• Organic preference
• Concerns about glyphosate in conventional wheat

So I tested it. Here’s the straight answer breakdown.

Quick Comparison

What’s the Real Difference?

Protein Content

• All Purpose flour: usually 10 to 11.7 percent
• Bread flour: usually 12 to 14 percent

That extra protein in bread flour means more gluten potential. More gluten means stronger dough structure.

That’s it. That’s the main difference.

FAQ

1. If I feed my starter AP, does it matter what I bake with?

No.

Your starter adapts to what you feed it. If it’s strong and active, it does not care whether your final dough uses AP or bread flour.

You can feed AP and bake with bread flour.
You can feed AP and bake with AP.
You can feed bread flour and bake with AP.

The starter will adjust.

2. Will my loaf collapse if I switch to AP?

Not if your technique is solid.

Here’s what changes:

With bread flour:
• Stronger dough
• Easier to build tension
• Higher oven spring
• More open crumb potential

With AP flour:
• Slightly softer dough
• Slightly less elasticity
• May spread more
• Crumb often a little more even and tender

If your shaping is good and fermentation is dialed in, AP works beautifully.

3. Will hydration need to change?

Usually yes, slightly.

Bread flour absorbs more water.
AP flour absorbs a little less.

If your bread flour dough was 72 percent hydration, your AP version may feel looser at that same percentage.

You may need to:
• Drop hydration 1 to 3 percent
or
• Add folds to strengthen structure

Small tweak. Not dramatic.

4. What about sandwich bread?

Honestly, AP shines here.

Sandwich loaves benefit from:
• Softer crumb
• Slightly less chew
• More tender bite

Bread flour can sometimes make sandwich loaves a little tougher if you are not careful.

If you’re after soft, everyday slicing bread, AP is more than fine.

5. What about artisan loaves with big open crumb?

Bread flour gives you a wider margin for error.

AP can absolutely produce open crumb. But:
• You need proper fermentation
• You need good shaping
• You cannot overproof

If you are pushing very high hydration, bread flour is more forgiving.

6. Is organic AP weaker?

Not necessarily.

Organic has nothing to do with protein strength. It only speaks to how the wheat was grown and treated.

If you are leaning organic because of glyphosate concerns, that is a reasonable choice. Organic certification prohibits synthetic herbicides like glyphosate.

From a baking standpoint, check the protein on the bag. That’s what matters structurally.

7. Why I’m Switching

Here’s my reasoning:

• Costco organic AP is cheaper per pound
• I already feed my starter AP
• I prefer organic whenever possible
• I want to reduce exposure to herbicides where I can
• For sandwich loaves and daily bread, I do not need extreme gluten strength

If I were running a bakery pushing 80 percent hydration show loaves daily, I might rethink it. But for home baking? It works.

Practical Advice If You Switch

Do not overthink it.

  1. Keep everything the same for the first bake.

  2. Watch dough strength during bulk.

  3. Add one extra fold if needed.

  4. Tighten your shaping slightly.

If it spreads a bit more the first time, adjust hydration next round by 1 to 2 percent.

That is how you dial it in. Small moves, one at a time.

Bottom Line

Bread flour gives you strength.
AP flour gives you softness.

Both make excellent sourdough.

If cost and organic sourcing matter to you, AP is a completely valid choice. You are not ruining your bread. You are just slightly changing the character of it.

And honestly, if your process is strong, your flour choice becomes less dramatic than people think.