Step 1

For The Mash: Adjust oven rack as close as possible to broiler element and preheat broiler to high. On a foil-lined rimmed baking sheet, arrange 10 1/2 ounces (300g) peppers in a single layer. Broil until peppers are blistered and well charred, 5 to 8 minutes per side. Cooked peppers should weigh about 7 ounces (200g) after broiling. Let peppers cool completely before using.

Step 2

In a food processor, pulse charred peppers, remaining 14 1/2 ounces (400g) fresh peppers, water, tamari, and salt until coarse mash forms, 16 to 20 pulses.

Step 3

Transfer pepper mash to a clean wide-mouth, 1-quart canning jar. Tap jar lightly on palm to remove any air pockets. Cover surface of mash with plastic wrap, pressing gently to ensure full contact, and weigh down with fermentation weight or small jar lid. Seal jar with airlock lid following manufacturer's instructions.

Step 4

Store pepper mash in dark area away from sun and let ferment, maintaining an ambient temperature between 55°F (13°C) and 75°F (24°C), for 7 days; check mixture daily for signs of gas formation (mash will climb up sides of jar; this is a good sign). Starting on the 7th day, taste mash daily until it has reached a pleasantly sour flavor (like sauerkraut); the total fermentation time can take anywhere from 7 to 21 days.

Step 5

To Finish the Hot Sauce: Scrape mash into a blender. Add vinegar, sugar, and salt, and blend on high speed until smooth, about 1 minute. With blender running, slowly stream in garlic oil and blend until smooth and emulsified, about 1 minute longer. Measure pH using strips or pH-meter to make sure sauce is about 3.4; if it is too high, lower pH to 3.4 with more vinegar as needed.

Step 6

Strain sauce through fine-mesh strainer set over a nonreactive bowl or large container, pressing on solids to extract as much liquid as possible; reserve solids for another use (see note).

Step 7

Transfer strained hot sauce to glass bottles or jar, cover, and keep refrigerated until ready to use. Sauce will keep refrigerated for up to 1 month.