Let the dough bulk ferment at room temperature for approximately 4–6 hours.
Don't rely solely on the clock to determine when bulk fermentation is finished. The temperature of your kitchen, starter strength, and the temperature of your dough can all affect how quickly it ferments.
How to tell when bulk fermentation is finished
The dough should look noticeably expanded, puffy, and aerated. Look for an increase in volume of roughly 50–75%, rather than necessarily doubling. The surface should look smoother and slightly domed with bubbles, and you should be able to see bubbles along the sides and underneath the dough. When you gently shake the bowl, the dough should have a light, airy, jiggly quality. It should also feel lighter and more elastic than it did when you first mixed it.
If the dough still looks dense and feels heavy, give it more time. If it has become extremely loose, very bubbly, and difficult to handle, it may have gone too far.
The temperature of your kitchen will make a big difference. A warm kitchen may bring the dough to the end of bulk fermentation closer to 4 hours, while a cooler kitchen may require closer to 6 hours or longer.