In a large bowl, dissolve yeast in water. Add the flour, oil and salt, stirring until blended. The dough will be shaggy and sticky. Cover bowl with plastic wrap. Let the dough rest at least 8 hours, preferably 12 to 18, at warm room temperature, about 70 degrees.
The dough is ready when its surface is dotted with bubbles. Lightly flour a work surface and place dough on it. Sprinkle it with a little more flour and fold it over on itself once or twice. Place dough on cookie sheet lined with parchment paper. Cover loosely with plastic wrap and let it rest for about 15 minutes.
At least 20 minutes before the dough is ready, heat oven to 475 degrees. Put a 6- to 8-quart heavy covered pot (cast iron, enamel, Pyrex or ceramic) in the oven as it heats. When the dough is ready, carefully lift off the lid leaving the pot still in the hot oven. Slide the dough off the cookie sheet and let the dough and parchment paper drop into the pot. The dough will lose its shape a bit in the process, but that’s OK.
Cover and bake for 30 minutes. Remove the lid and bake another 15 to 20 minutes, until the loaf is beautifully browned. Remove the bread from the Dutch oven and let it cool on a rack for at least 1 hour before slicing.