Steps
1. Wearing gloves, stem and roughly chop all the peppers (seeds included for maximum heat).
2. Roast the serrano peppers under a broiler or on a grill until skins are charred, then peel and chop.
3. Combine all peppers, garlic, sea salt, and sugar in a clean glass jar.
4. Add filtered water to cover the peppers, leaving an inch of headspace.
5. Seal the jar with an airlock lid or loosely with a lid to allow gases to escape.
6. Let ferment at room temperature (68-72°F) for 7 to 10 days, tasting daily after day 5.
7. Once desired tanginess is reached, blend the fermented peppers with apple cider vinegar until smooth.
8. Strain if desired for a smoother sauce.
9. Transfer to a clean bottle and refrigerate; flavor will develop over time.
10. Use sparingly to add heat and complexity to dishes.