Step 1

Pulse chiles and kosher salt in a food processor until a coarse purée forms. Transfer to a 1-qt. glass jar, loosely screw on lid, and let stand at room temperature for 12 hours to ferment slightly.

Step 2

Stir in vinegar and loosely screw on lid. Let chile mixture stand at room temperature for at least 1 day and up to 7 days. (Taste it daily; the longer it sits, the deeper the flavor becomes.)

Step 3

Purée mixture in a food processor or blender until smooth, about 1 minute. Place a fine-mesh sieve inside a funnel. Strain mixture through sieve into a clean glass bottle. (Hot sauce will become thinner and may separate after you strain it; shake vigorously before each use.)

Step 4

DO AHEAD: Can be made up to 4 months ahead. Keep refrigerated.