To make sriracha sauce, puree serrano and jalapeno peppers along with garlic, salt, brown sugar and water, and allow the puree to ferment for a few days. Then, blend the fermented puree with vinegar, strain it, and cook till the desired consistency is achieved. Cool the sauce, and store.
Start with 1/2 pound of red serrano and 1 pound of red jalapeno peppers. For a spicier sauce, use jalapeno and serrano peppers in a 3:1 ratio. Also, use 4 garlic cloves, 3 tablespoons of light brown sugar and 1 tablespoon of kosher salt.
To make a puree of these ingredients, chop the peppers, peel the garlic, and put them in a blender. Add the sugar, salt and 1/3 cup of water, and blend to a smooth consistency. Pour the puree into a pitcher, cover with a plastic wrap, and allow it to ferment in a dark and cool area for three to five days. Each day, stir the mixture once, taking care to scrape the sides every time. Allow the mixture to bubble well.
Next, blend the fermented mixture with 1/2 cup of distilled white vinegar to a smooth consistency. Filter it through a fine strainer. Transfer the sauce to a saucepan, and boil it for five to 10 minutes or until the desired thickness is achieved. Stir the sauce often when boiling, and if needed, skim the foam.
Finally, turn the heat off, cool the sauce, pour into a glass jar, and refrigerate.