Fresh Milled Sourdough Hydration Guide

Hydration is the single biggest variable separating a beautiful fresh-milled sourdough from a dense, gummy brick. Fresh-milled flour behaves differently from commercial flour for one essential reason: the bran is still there. Bran is thirsty. It absorbs water slowly, holds onto it, and changes the dough's feel from the moment you mix it through the entire ferment.

What hydration actually means

In baker's percentages, hydration is the weight of water divided by the weight of flour, multiplied by 100. A dough with 800g of water and 1000g of flour is 80% hydration. The starter contributes both flour and water — count both halves.

• 100g of 100%-hydration starter = 50g flour + 50g water
• Total flour = recipe flour + flour from starter
• Total water = recipe water + water from starter
• Hydration = total water ÷ total flour × 100

Why fresh-milled needs more water

Whole-grain flour contains intact bran, which is dense, fibrous, and highly hygroscopic. A given weight of fresh-milled whole wheat absorbs noticeably more water than the same weight of commercial bread flour because that bran is greedy for hydration. Without enough water, the bran competes with the gluten network for moisture and produces a tight, dense crumb.

Fresh-milled flour also has not had its starches damaged by the multi-pass commercial milling process, so it absorbs water more slowly. This means hydration that feels right immediately after mixing may feel too wet, and a dough that feels too dry initially often becomes perfect after a 30-minute rest.

Hydration ranges by grain

Hard red wheat / hard white wheat (the workhorses)

• Sandwich bread: 75–80%
• Hearth loaves / boules: 80–85%
• Sourdough boules with open crumb: 85–88%
• Focaccia / ciabatta: 85–95%

Rye

• 100% rye pan loaf: 75–80%
• 100% rye sourdough: 80–90%
• 70/30 wheat-rye blend: add 5% to the wheat recipe's hydration
• 50/50 wheat-rye blend: add 10%

Einkorn

• 100% einkorn sourdough: 60–70% (yes, that low — einkorn's gluten is weak and overhydrated dough collapses)
• Einkorn blends: hydrate the einkorn portion at 65%, the rest of the flour at its normal hydration

Spelt

• 100% spelt sourdough: 70–78%
• Spelt blends: closer to wheat hydration, but shorten bulk by 20%

Multi-grain blends

Weight-average the grains' target hydrations. A loaf that's 60% hard red wheat, 30% spelt, and 10% rye targets roughly (0.6 × 82%) + (0.3 × 74%) + (0.1 × 85%) = 79.9%. Then add 2–3% for the rye's bran-heavy effect.

The autolyse: your hydration safety net

Autolyse (sometimes spelled autolysis) is a rest period after mixing flour and water but before adding salt and starter. For fresh-milled flour, autolyse is essential. A 30–60 minute rest gives the bran time to fully hydrate. The dough will feel dramatically firmer at the end of autolyse than at the start, and you'll know whether to add a splash more water or proceed.

Skip autolyse and you'll consistently underestimate hydration. The dough will feel right at mix, then loosen during bulk as the bran finally absorbs its share, leaving you with a slack, spread-out loaf.

Reading dough by feel

Too dry

• Dough feels tight, springy, and won't accept more flour during mixing.
• After 30-minute rest, dough is still firm and dense.
• Surface tears rather than stretches when you do windowpane.
• Finished loaf has tight, dense crumb and pale crust.

Just right

• Dough is tacky but not gluey — releases from clean hands with a brief lift.
• Stretches and folds smoothly without tearing.
• After bulk ferment, dough is jiggly, airy, and holds shape when scraped from bowl.
• Bakes with open, irregular crumb and crisp crust.

Too wet

• Dough is soupy, won't hold shape, smears across the bench.
• Bench scraper required for any handling.
• Bulk ferment doesn't produce visible structure or windowpane.
• Finished loaf spreads flat, has gummy crumb, pale crust.

Adjusting hydration as you go

Treat published recipes as starting points. The same recipe in different kitchens — at different humidities, with different mills, with different grain batches — can need 3–5% more or less water to produce the same dough feel. After your first attempt:

1. If the crumb was tight and dense → add 3% water next time.
2. If the loaf spread flat → reduce water by 3% and shorten bulk by 20%.
3. If the dough felt right but the crumb was gummy → underbaked. Same hydration, bake longer.
4. If the dough felt fine but the crust was pale → too dry. Add 2% water and steam the oven more.

Bran softens — plan for it

Sharp, freshly-milled bran particles soften over the course of bulk fermentation as acids in the dough work on them. This means a dough that feels appropriately firm at mix often feels slack at the end of bulk. That's normal and not a sign of overproofing — the bran has simply given up its water. Shape it as you would any other dough; the shape will hold because the gluten structure has developed alongside the softening bran.

Cold retard and hydration

A cold retard (overnight refrigeration of shaped loaves) tightens dough as it cools and the gluten network firms. This is forgiving — a loaf that looks borderline-overproofed when you shape it will often firm up beautifully overnight. Don't reduce hydration to compensate for cold retard; let the fridge do that work for you.

Troubleshooting by symptom

• Crumb dense and gummy: probably underhydrated AND underbaked. Add water and extend bake.
• Crumb open but gummy: underbaked. Same hydration, bake to 205–210°F internal.
• Crumb tight and dry: overhydrated for the bran level, OR autolyse skipped. Try autolyse and reduce water 2%.
• Loaf spreads flat: overhydrated, overproofed, or both. Reduce water 3% and shorten bulk.
• Loaf wonderful but flavor flat: undersalted, not a hydration problem.