Add ¼ cup room temperature starter, ½ cup flour, and ½ warm water to a small bowl. Stir to combine. Cover loosely and leave on the counter for 6 hours or up to overnight.

Add the remaining flour, ½ cup room temperature beer, and 1 teaspoon sugar to the bowl. Stir until combined.

Add the dough to a well floured surface, kneading until the dough is no longer sticky and very elastic, about 20 minutes (this can be done in phases). Towards the end of kneading, add in the kosher salt (salt is very important for flavor but can impede the yeast so it’s best to add it last).

Oil the inside of a large bowl. Add the ball of dough to the bowl, loosely cover and allow to rise until doubled in size, about 4-6 hours.

Preheat the oven to 425F.

Once the dough has risen, it will probably also have spread. Gently tuck the sides under the dough to make a smaller, but higher, ball of dough, transfer to a lightly oiled Dutch oven. Using a sharp knife, slice the top of the bread in an X, sprinkle with coarse salt. Add the lid tightly onto the pot.

Bake for 50 minutes or until the dough has a hard crust and is dark brown.

Slice, serve warm.