Mix sourdough starter and room temperature beer in your KitchenAid mixer bowl. The beer will foam up.
Add sugar, salt and flour, and combine using your mixer dough hook attachment until it has achieved a soft dough. Knead for 3-4 minutes in the mixer bowl, then cover and allow to rise, 2-2.5 hours. When you push the dough with your finger the indentation should remain.
Dump the dough on a lightly floured surface and cut into two (if you desire two smaller loaves). Shape each into a round or oblong loaf on top of a large piece of parchment paper; loosely cover.
Allow the bread 2 additional hours to rise. During the last half hour, preheat the oven to 450 degrees F. Place your dutch oven inside as the oven preheats.
Once the oven is preheated, dust the bread with flour and score with a sharp knife. Carefully pick up the parchment and transfer the bread to the dutch oven.
Bake, covered, at 450 degrees F for 25 minutes. Carefully remove the lid and bake for an additional 12-15 minutes.
Remove from the oven when the bread is dark brown and sounds hollow when tapped. Allow to cool before enjoying.