Place the cabbage wedges in a large bowl filled with water and add a small splash of vinegar. Let soak for 10 minutes, then rinse thoroughly several times and drain.

In a clean 1.5-gallon glass jar, add half of the garlic cloves, half of the serrano chilies, half of the bay leaves, and 1 tablespoon of the peppercorns.

Pack the jar about three-quarters full with cabbage wedges, pressing them down tightly.

Add the remaining garlic, chilies, bay leaves, and peppercorns. Add the kosher salt and brown sugar at this stage.

Fill the jar with more cabbage wedges, pressing down firmly to pack everything in.

Pour in the apple cider vinegar, then fill the jar to the top with room-temperature filtered water, making sure the cabbage is fully submerged.

Seal the jar tightly and shake well to help dissolve and distribute the salt and sugar.

Leave the jar at room temperature for 2 days to ferment.

After 2 days, transfer the jar to the refrigerator. The cabbage will continue to develop flavor and will keep for several months when refrigerated.