Why flour type matters: the protein content that determines everything
All wheat flours share the same basic structure: starch, protein, fat, and a small amount of moisture. What separates cake flour from bread flour isn't the wheat variety alone — it's the protein content, and specifically the two proteins that form gluten (gliadin and glutenin) when hydrated and worked. Gluten is the network that makes bread chewy and elastic, that makes pasta hold its shape, that makes croissants flaky (when layered with fat), and that makes cake tender (when minimized). Understanding protein percentage as the governing variable in flour behavior gives you a predictive framework for baking decisions, not just a list of rules to memorize.
High protein = more gluten = more structure = chewier, stronger, more elastic. Low protein = less gluten = less structure = more tender, crumbly, delicate. A bread recipe needs the former; a wedding cake needs the latter. The flour types below are organized by protein content, which is the most useful organizing principle for a baker.
The complete flour comparison table
Cake flour: 7-9% protein
The most tender flour. The low protein means minimal gluten development, producing a fine, delicate crumb. Used in: white and yellow layer cakes, angel food cake, chiffon cake, some muffins, biscuits. 114g per cup. King Arthur and Swans Down are the common brands. Note: cake flour is bleached and treated with chlorine, which acidifies the starch and helps it set at lower temperatures — relevant in high-sugar cakes that would otherwise fall.
Pastry flour: 8-10% protein
Between cake and AP. Slightly more structure than cake flour but more tender than AP. Used in: pie crust (produces flakier result than AP), scones, pancakes, some cookies where extra tenderness is desired. 120g per cup. Less commonly stocked; AP flour is often used instead with slight technique adjustment.
All-purpose flour (AP): 10-12% protein
The do-anything flour of home baking. Protein range varies by brand: King Arthur AP is 11.7%, Gold Medal is 10.5%, Bob's Red Mill is 11%. This matters slightly — KA produces chewier cookies and better pizza than Gold Medal. 125g per cup (Stella Parks standard) or 120g (King Arthur).
Used in: cookies, quick breads, muffins, pancakes, most cakes, casual bread, pancakes. Substitutes adequately for most bread flour applications with minor texture trade-offs.
Bread flour: 12-14% protein
The highest-protein widely available wheat flour. Produces strong gluten networks that can trap carbon dioxide bubbles from yeast — the mechanism behind the rise and chew of bread. 136g per cup. Used in: sandwich bread, sourdough, baguettes, pizza dough, bagels, pretzels, challah. Can substitute in cookies (slightly chewier result — some bakers prefer it for chocolate chip cookies).
00 flour: 9-12.5% protein (fine grind)
Italian designation for particle size, not protein — "00" means double-zero (very fine grind). Can be either high or low protein depending on the wheat blend. Caputo "Pizzeria" 00 is 12.5% — high protein, for pizza dough. Caputo "00 Pasta" is softer, around 11-11.5%. The fine grind creates silkier dough texture that's extensible (stretches without springing back) — ideal for hand-stretched pizza and fresh pasta. 130g per cup.
Substituting: AP flour for 00 produces slightly less extensible dough and a slightly denser crust. For casual home pizza, the difference is minor. For true Neapolitan pizza at 900°F+, 00 flour makes a noticeable difference.
Whole wheat flour: 13-14% protein (high, but functionally lower gluten quality)
Whole wheat retains the bran and germ, which contain fiber, B vitamins, minerals, and fat. However, the sharp bran particles physically cut gluten strands during mixing, reducing the effective gluten network. A 100% whole wheat bread has high protein content but lower gluten development than bread flour. Result: denser, heavier bread.
Best practices for whole wheat baking: blend with AP or bread flour (50/50 is most approachable; 70/30 whole wheat/bread is more nutritious). Increase hydration by 2-3% per cup of whole wheat added (bran absorbs water). Rest the dough 30-60 minutes after mixing (autolyse) to let the bran hydrate fully before kneading.
127g per cup. Shelf life at room temperature: 3 months (bran fat goes rancid). Store in freezer for longer.
Rye flour: 8-12% protein (unique gluten behavior)
Rye contains proteins that form a different type of gluten — gliadin but very little glutenin — which produces a dense, gummy dough rather than an elastic one. Rye can't be used alone in yeasted bread; it must be blended with wheat flour. Max practical ratio: 40% rye, 60% wheat. Used in: dark pumpernickel bread, rye sourdough, crackers, some European pastries. 102g per cup.
Semolina: 12-13% protein (durum wheat)
Made from durum wheat, the hardest wheat variety. Very high protein, granular texture (coarser than other flours). Used in: dried pasta (extruded shapes), some Mediterranean breads, pizza dusting, and couscous. 167g per cup. Not directly substitutable for AP flour in most applications — too coarse and produces very different texture.
Gluten-free 1:1 blends: varies
Typically rice flour + tapioca starch + potato starch + xanthan gum. The xanthan gum mimics gluten's binding and structure functions. Performance depends heavily on brand. King Arthur Measure-for-Measure is the most reliable for direct 1:1 substitution in cookies, cakes, and quick breads. Weigh rather than measure by volume — blends have inconsistent cup weights.
Grams per cup — the numbers that matter for baking by weight
- Cake flour: 114g/cup
- Pastry flour: 120g/cup
- AP flour: 125g/cup (Stella Parks) or 120g (King Arthur own recipes)
- Bread flour: 136g/cup
- 00 flour: 130g/cup
- Whole wheat: 127g/cup
- Rye flour: 102g/cup
- Semolina: 167g/cup
- GF 1:1 blends: varies — weigh
What breaks when you substitute one flour for another
- Bread flour in cookies: Chewier, slightly tougher cookies with more structure. Many professional recipes (including Serious Eats' chocolate chip cookies) specify bread flour intentionally. Works well for fudgy brownies too.
- Cake flour in yeasted bread: Inadequate gluten for rise and structure. Bread will be dense, flat, and gummy. Don't do this.
- AP in pizza: Works for casual pizza; slightly softer, less extensible crust. For proper Neapolitan-style, 00 pizza flour makes a meaningful difference.
- 100% whole wheat in any recipe: Always heavy and dense. Always blend with at least 30-50% AP or bread flour. Always increase hydration.
- 100% rye in bread: Won't rise properly and has an extremely dense, gummy texture. Max 40% rye in any yeasted bread.
- GF 1:1 in yeasted bread: Works but requires additional xanthan gum if not included in the blend. GF bread is fundamentally different from wheat bread in texture — accept this rather than trying to make them identical.
DIY flour approximations
Simulate cake flour from AP: for every cup of AP flour, remove 2 tbsp and replace with 2 tbsp cornstarch. Sift together twice to ensure uniform distribution. This reduces protein concentration and adds starch, producing results that are 85-90% equivalent to cake flour in most cake recipes.
Boost AP toward bread flour: add 1 tbsp vital wheat gluten per cup of AP flour. This increases the protein content by approximately 2-3%, giving AP flour closer to bread flour's gluten-building capacity. Useful for pizza dough and artisan bread.
Nutrition: whole grain vs. refined
Whole wheat flour retains the bran (outer layer) and germ (embryo), contributing fiber, B vitamins (niacin, thiamine, folate), minerals (iron, magnesium, zinc), and healthy fats from the germ oil. Refined AP flour retains only the starchy endosperm. In the US, AP flour is enriched with some B vitamins added back, but fiber and many micronutrients are still lower than whole wheat.
Practical nutrition approach: blend 30-50% whole wheat into bread, pancakes, muffins, and other baked goods. This captures meaningful nutritional improvement without the texture penalties of 100% whole wheat.
Storage guide
- AP, bread, cake, pastry flour: airtight bin in a cool pantry, 6-8 months. Transfer from paper bag immediately upon purchase.
- Whole wheat and rye: the bran fat goes rancid within 3 months at room temperature. Store in the freezer in an airtight container for up to 12 months. Bring to room temperature before using (cold flour can inhibit yeast activity).
- GF blends: airtight container, 6 months room temperature. Refrigerate for longer.
- Semolina: 1 year in an airtight container at room temperature.
Rancid flour smells like crayons, oil paint, or nail polish remover. When in doubt, smell it. If it smells wrong, discard.
Frequently asked questions
Can I use bread flour in brownies? Yes — slightly chewier, more structured brownies. The Serious Eats brownie recipe uses bread flour intentionally. If you prefer fudgier, more tender brownies, stick with AP or cake flour.
Is self-rising flour the same as AP? No — self-rising is AP flour pre-mixed with baking powder (1.5 tsp/cup) and salt (¼ tsp/cup). If you substitute it, remove the additional leavening from the recipe and reduce salt accordingly. Adjust amounts to match your recipe's exact leavening needs.
What flour for sourdough? Bread flour is standard. Most artisan bakers blend bread flour with 10-20% whole wheat for additional flavor and fermentation food (whole wheat feeds wild yeast more actively). 100% bread flour sourdough produces the best rise; 80/20 bread/whole wheat produces more complex flavor.
00 flour vs. semolina for fresh pasta? 00 flour for tender, silky fresh pasta (ravioli, fettuccine, lasagna sheets). Semolina for firmer pasta that holds shape in extrusion (rigatoni, penne). A blend (50/50 00 and semolina) produces excellent hand-rolled pasta with good bite.
Does bleached flour matter? Bleached AP flour undergoes chemical treatment (benzoyl peroxide or chlorine dioxide) that whitens the flour and slightly weakens the gluten. Unbleached AP develops more gluten and is preferred by most bakers. For cake flour, chlorine bleaching is actually functional (it acidifies the starch, improving cake structure in high-sugar formulations). For everyday bread and cookie baking, unbleached AP is the better choice.
Related: cups to grams, dough hydration, pizza dough math, sourdough starter.