After its overnight slumber, your levain should show some signs of activity.

Feel free to look at, smell, and poke the dough and appreciate how these simple ingredients transformed overnight. There should be some bubbles in the dough - that's the yeast starting to generate gas, which will leaven the loaf in the oven. The dough may smell funky or have just a hint of sour, depending on time and temperature.

These are early signs of microbial activity that will continue to evolve and progress.

Now, it's time to feed these sourdough microbes with more flour and knead the main dough to get it ready for rising and baking.