Walnut sourdough bread is our whole grain everyday loaf with 200 grams of walnuts folded through it — nuts in every single slice. The one step most recipes leave out is blanching the walnuts first, which takes the bitterness out before they ever reach the dough. Everything else is the slow overnight ferment you already know.

Walnut Sourdough Bread

A hearty whole grain walnut sourdough with a deep, nutty flavor — the walnuts blanched first to take the bitterness out.

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Prep Time 45

Cook Time 35

Fermenting & proofing 20

Total Time 21 20

Servings: 1 loaf

Course: Bread, Breakfast

Cuisine: Nordic, Scandinavian

Ingredients Equipment Method Notes

Ingredients

Walnuts

200 g walnut halves about 1¾ cups — blanched, see step 1

Dough

140 g active sourdough starter about ⅔ cup — bubbly, ripe, and passing the float test
400 g water about 1⅔ cups, lukewarm
300 g bread flour about 2⅓ cups — or sifted landhvete
150 g whole wheat flour about 1¼ cups
100 g coarse stoneground whole wheat flour about ¾ cup
15 g fine sea salt about 2½ tsp

For the basket

2 tbsp rice flour for dusting the linen cloth — it doesn't absorb, so the dough releases cleanly

Equipment

Digital kitchen scale This dough runs at 73% hydration — weight, not cups.
Banneton proofing basket, 9–10 in Holds the shape through the overnight chill. Dust with rice flour; a heavy nut dough sticks more than a plain one.
Linen proofing cloth Rice flour plus linen is the combination that releases cleanly with inclusions in the dough.
Bench scraper Folding 200 g of walnuts into a wet dough is where hands alone start tearing it.
Bread lame or scoring knife A clean, deep score. Walnut halves near the surface will catch a dull blade.
Perforated baking sheet We bake straight on a preheated perforated sheet — no Dutch oven needed.
Metal roasting tray Your steam source, on the bottom rack. Metal only — never glass.
Instant-read thermometer 96–99°C / 205–210°F in the center. Nut breads look done before they are. Chef-tested pick.

Method

Day 1

Blanch the walnuts. Bring a small pot of water to a boil, add the walnuts and boil for 1–2 minutes. Drain, rinse under cold water and drain well. Spread them out on a towel while you mix the dough. One blanch is enough, and they don’t need to be bone dry — damp is fine. This step is what separates a nutty loaf from a bitter one; see the notes below.
Mix everything except the salt: starter, water and all three flours. Mix until no dry flour is left. Cover and rest 1 hour.
Add the salt and work it through the dough until it’s fully incorporated and the dough feels smoother.
Stretch and fold every 30 minutes, at least 4 sets. Fold the walnuts in on the second set — flatten the dough, scatter them over the surface, fold, and let the remaining sets distribute them evenly.
Shape the dough into a round and place it seam-side up in the banneton, lined with a linen cloth dusted with rice flour. Press any walnut that pokes out back into the dough as you shape.
Cover and refrigerate overnight.

Day 2

Preheat the oven to its maximum with the perforated baking sheet on the middle rack and the metal roasting tray on the bottom rack.
Turn the loaf out onto parchment, seam-side down. Score it once, decisively, about 1 cm deep.
Slide the loaf onto the hot sheet and pour boiling water into the roasting tray for steam. Bake at 250°C / 480°F for 20 minutes.
Remove the tray, drop the heat to 200°C / 390°F and bake another 15 minutes, until the crust is deep brown and the center reads 96–99°C / 205–210°F.
Cool on a wire rack for at least 2 hours before slicing. A nut loaf holds moisture longer than a plain one — cutting early gives you a gummy crumb.

Notes

Chef tip: Why we blanch the walnuts. The bitterness in walnuts sits in the papery brown skin — tannins, plus a compound called juglone. A short boil pulls a good part of it out, and you’ll see it in the water. Skip this and the bitterness carries straight into the crumb and gets sharper as the loaf ferments. Two minutes of work, and it changes the whole loaf.

Damp walnuts are fine. Straight from the towel into the dough is how we do it — no toasting, no drying in the oven. Slightly damp nuts fold in without tearing the dough, and they carry a little of that water into the crumb, which is no problem at this hydration. Just don’t tip the draining water in with them.

Sticky is right. The whole grain flours drink up water, so this sits around 73% hydration. It’ll feel tacky — that’s exactly what you want.

Nuts slow things down. Walnut tannins are mildly hostile to gluten and to your starter, so this dough can ferment a touch slower and feel a little slacker than the plain loaf. Judge the dough, not the clock.

Let the fridge do the work. The overnight cold rise does the heavy lifting — better flavor, easier scoring, and a taller loaf. Don’t skip it.

Walnuts on the surface will char. Anything sticking out of the crust burns before the loaf is done. Push them back in when you shape, or accept a few dark ones — they taste fine, they just look darker than the crust.

Blanch the walnuts — the trick to a walnut sourdough that isn’t bitter

Walnut bitterness lives in the thin brown skin around the kernel: tannins, and a compound called juglone. In a salad you barely notice it. In a loaf that ferments for 20 hours, it concentrates, and you end up with a bread that has a hard, astringent edge behind the nuttiness.

A one to two minute boil pulls a lot of it out. Drain the walnuts and you’ll see the water has gone brown — that’s exactly what you don’t want in your crumb. Rinse, drain, and they’re ready.

One blanch does it, and there’s no need to dry them out afterwards. Damp walnuts go straight into the dough. A bone-dry walnut half tears wet dough as you fold it in; a slightly damp one doesn’t.

Folding 200 g of nuts into a wet dough

Two hundred grams is a lot of walnuts — about 36% of the flour weight — and adding them at the wrong time makes a mess. Two rules:

Add them on the second set of folds, not at mixing. The dough needs to build some strength on its own first. Fold them in too early and the nuts cut the gluten as it’s trying to form.

Spread, don’t dump. Flatten the dough out, scatter the walnuts over the surface, then fold. The remaining sets will distribute them for you. Working them in all at once means squeezing the dough, which is what tears it.

When you shape the loaf, run your hand over it and press any walnut that’s poking out back into the dough. Nuts on the surface go from toasted to burnt long before the loaf is baked through.

Make it your own

The dough doesn’t care what you fold into it, as long as the weight stays around 200 g:

Toast the walnuts after blanching, if you want them crisper — 8–10 minutes at 175°C / 350°F, cooled before folding in. We don’t bother; most of that crunch comes back in the bake anyway.
Hazelnuts — blanch and rub the skins off, then use them whole. Sweeter and less tannic than walnuts.
Pumpkin or sunflower seeds — soak them in warm water for 30 minutes first, otherwise they pull water out of the dough and dry the crumb.
Walnuts and dried figs, half and half — a good loaf for cheese.

The blanching is specifically a walnut problem. Hazelnuts and seeds don’t need it.

More Nordic bakes you’ll love

Whole Grain Sourdough Bread — the base dough this loaf is built on
Beginner Sourdough Bread (Your First Loaf) — start here if this is your first sourdough
How to Make a Sourdough Starter — the starter that leavens all of it

Walnut Sourdough Bread