Walnut Levain

This is my imitation of Acme Bakery's walnut levain. It's based on the Mixed Starter bread recipe in Baking With Julia. If you're not comfortable working with doughs by feel, if you really prefer to weigh ingredients, this recipe will not be helpful to you.

First starter:

• 1 walnut sized piece of white-bread dough (this can be saved and frozen)
• 1/4 cup warm water
• 2/3 cup bread flour

Thaw the old dough, if necessary, and cut/break it up into the water. Let soak 5 minutes or so, then mix in the flour. Knead to mix thoroughly (no need to develop gluten here). You're looking for quite a firm dough here. Let rise overnight.

At the same time:

• 2 tablespoons liquid sourdough starter (whatever you have in a jar)
• 1/4 cup rye flour
• 1/4 cup WW flour
• 1/2 cup bread flour
• 1 cup warm water

Mix all together. Set out overnight (you will have two covered bowls sitting out overnight, the first starter, and this sourdough mixture).

Second starter:

• first starter, cut up into
• 1/4 cup warm water
• 3/4 cup bread flour

As before, let the previous dough soak in the water for a while, then add the flour and mix/knead. Again, you're looking for a moderately stiff dough. (feels like 50% hydration, perhaps?). Let this rise 4 hours or so.

The sourdough mixture should be well-active by this time, approaching "mature" (not growing any more, starting to deflate a little), and the second starter should be well-risen (doubled, soft, ideally with some visible bubbles under the surface). When the second starter and the sourdough mixture are as described, which should be at least 4 hours, but could be more. place them both in the fridge for at least an hour, but longer is fine. The sourdough mixture is used for flavor, not really leavening, so you don't need to be very fussy about how mature it is.

Final Dough:

• 1/2 tsp yeast proofed in:
• 1/4 cup warm water
• all of the second starter, cut up into the previous water
• 1 tablespoon salt
• all of the sourdough mixture
• approximately 2 cups bread flour

Let things warm as appropriate to manage your final dough temperature (you're shooting for around 75F, of course), and begin adding sourdough mixture and flour to the water/yeast/starter mixture. Add the salt fairly early. When you have acheived a shaggy mass, begin to knead. You're looking for around a 65% hydration dough here, moist but not particularly hard to manage. Knead thoroughly, 8-10 minutes by hand.

Now add 1 cup of coarsely chopped walnuts. Knead them in gently, enough to ensure they're evenly mixed in.

• proof for 2-3 hours, with a stretch and fold or similar every hour, until you have good development
• shape as desired (I use a boule)
• final rise approximately 1 hour
• bake at 425 or so, with steam, 45-50 minutes.

Baking will take longer than you might guess due to the walnuts. The crust should be more brown than golden.