Cut cauliflower into small 1-inch florets, discarding any large stems. You will have about 2 loosely packed cups (about 6 to 8 ounces)

In a small saucepan over medium heat, combine the water, vinegar, sugar, and salt, stirring just until both dissolve. Remove from the heat

Add cauliflower florets and chiles to the glass jar. Add black peppercorns and coriander seeds

Pour the vinegar brine into the jar, filling it to submerge the florets.

Allow the brine cool to room temperature, close the jars, and refrigerate the jars for at least 48 hours before serving.