This makes what might be inappropriately termed a “hella big loaf of bread.” It’s big enough that I often cut it immediately into quarters, wrap two of them well, and pop them in the freezer. If you don’t want to bake this bread in a Dutch oven, you can make a couple of sandwich loaves in traditional loaf pans with the dough — just cut the baking time in half to start.

3 cups sourdough sponge
1 cup lukewarm water
2 tablespoons honey
5 cups flour of your choice (I like white whole wheat for this)
1 tsp. salt

In a large bowl — preferably a stand mixer fitted with a dough hook — combine the sponge, water, and honey. Mix well.
With the mixer running, gradually add the flour and salt. Allow the dough to mix until all the ingredients are well incorporated and there are no big lumps of flour remaining, about 3-5 minutes. Cover the bowl with a clean tea towel and set in a warm place, free of drafts, for 3-4 hours. The dough should rise slightly (though it probably won’t entirely double in size) and feel slightly puffy to the touch, but will still be quite sticky.
Generously butter a Dutch oven (I use an enameled cast iron one) and turn the dough out into the prepared pan. Lightly smooth the top as needed.
Cover the Dutch oven and allow to rise again, for another 2-3 hours, until the dough has visibly grown in volume.
Preheat oven to 400 degrees. With a sharp knife or scissors, slash the top of the bread once or twice. Cover your Dutch oven with a tight-fitting lid and bake the bread for 25 minutes with the lid on; then remove the lid and bake the bread uncovered for an additional 25-30 minutes, until the bread is golden brown and the slash in the top has risen and become crusty.

Allow the bread to cool in the Dutch oven for 10-15 minutes, then carefully turn it out and finish cooling on a rack.