Prepare the peppers by removing the stems and seeds and placing them in the bowl of a food processor (or high-powered blender).
Add the salt, brown sugar and garlic to the bowl of the food processor and pulse until well blended.
Pour the pepper puree into a wide-mouth quart-sized Mason jar (using a funnel helps here).
Wipe the jar rim, if necessary, and add your airlock, pickle pipe or two-piece lid.
Let ferment at room temperature. Once daily, take a clean spoon and stir the ferment.
After you start seeing bubbles, allow it to ferment for a few more days until you notice the liquid stops increasing and starts to reduce slightly. (This is your sign the fermentation process is complete.)
Pour fermented sriracha into a high-powered blender and add 1/2 cup raw apple cider vinegar. Blend until completely smooth.
Transfer to a clean jar or hot sauce bottle and store in the refrigerator.