What's the difference between Medium Rye Flour and Dark Rye Flour (Pumpernickel)?

Medium Rye Flour: 9.00-10.50% protein, absorption 1.080×, hydration 80-95%. Dark Rye Flour (Pumpernickel): 8.00-9.00% protein, absorption 1.100×, hydration 90-110%.

Can I substitute Medium Rye Flour for Dark Rye Flour (Pumpernickel) 1:1?

Yes — absorption is close enough that a 1:1 swap works with minor tweaks.

Which is better for open-crumb sourdough?

Dark Rye Flour (Pumpernickel) supports higher hydration (up to 110%), making it better suited to open-crumb hearth loaves than Medium Rye Flour (max 95%).

Side-by-side comparison

Medium Rye Flour vs Dark Rye Flour (Pumpernickel)

	Medium Rye Flour	Dark Rye Flour (Pumpernickel)
Protein	9.00–10.50%	8.00–9.00%
Absorption (× bread flour)	1.080	1.100
Hydration range	80–95%	90–110%
Category	rye	rye
Ash %	1.50	2.00

Medium Rye Flour

Medium rye contains most of the rye grain with moderate bran content. Rye proteins do not form gluten like wheat proteins — instead, rye structure comes from pentosans (soluble fiber) that absorb 8-10x their weight in water. This means rye dough is sticky, paste-like, and requires different handling than wheat. Hamelman's reference specs target 80-95% hydration for rye-dominant doughs. Central Milling's Organic Medium Rye is the US reference. At 20-40% in a blend with bread flour, medium rye adds color, flavor complexity (tangy, earthy), and extends keeping quality. At 100%, expect dense crumb and strong sour flavor.

Dark Rye Flour (Pumpernickel)

Dark rye (pumpernickel flour) is coarser, contains more bran, and has the deepest flavor of all rye flours. Absorption is 10% higher than bread flour baseline. Ash content 2.0%+ indicates high mineral content from extensive bran inclusion. Used in traditional German pumpernickel (100% dark rye, 24+ hour steam bake) and Scandinavian rye breads. Hamelman's pumpernickel formula targets 95-100% hydration with 100% dark rye. Can also be used as 10-20% of a wheat-rye blend for strong rye character without going fully rye. Central Milling, Bob's Red Mill, and Janie's Mill are US reference sources.

Substitution math

When substituting Medium Rye Flour for Dark Rye Flour (Pumpernickel) in a recipe, absorption is close enough that a direct swap works. Expect minor texture differences but similar handling.

The gear that makes the math work

A short, honest baking kit. The scale matters most — every weight on this page is in grams. The Dutch oven is what turns a good crumb into a great crust.

Digital kitchen scale (0.1 g)
Baker's percentage is by weight, not volume — a 0.1 g scale is what makes the math on this page accurate.
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Dutch oven / combo cooker
Traps steam for the first bake phase — the single biggest factor in oven spring and a blistered, glossy crust.
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Banneton proofing basket
Wicks moisture and holds shape during the final proof, so high-hydration dough doesn't spread flat.
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Bread lame + bench scraper
A sharp lame scores clean ears; a steel bench scraper handles wet, sticky dough without tearing the gluten.
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High-protein bread flour
The math assumes ~12–14% protein. Real bread flour absorbs the hydration you calculate — all-purpose won't.
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Danish dough whisk
Mixes shaggy, high-hydration dough in seconds without the gluey mess of a spoon or your hands.
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🎧 Or learn the craft by ear

The numbers here are the what; a good baking book is the why. An Audible trial gets you any title free — Michael Pollan’s Cooked(the “Air” chapter is the best story ever told about why bread rises) is a perfect first listen.

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Gear guides — what actually matters