Every Vietnamese cook makes this dipping sauce, with the differences among them reflecting personal preferences and regional variations. In general, as you move south the sauce gets sweeter, hotter, and more garlicky. Yet no matter exactly how it is made, its role is always the same: to enhance and unify all the elements of a dish. As with much of Viet cooking, parameters apply more than rules. This recipe will help you develop your own version. Sensing subtle distinctions between sour, sweet, salty, and spicy requires practice. Plus, fish sauces differ, and even lime juice can be inconsistent. To deal with these variables, I don’t mix everything together at once, but rather break up the process to simplify matters for the taste buds. This allows for adjustments along the way. While you may omit the rice vinegar, it actually brightens the flavors and softens any harsh or bitter edges contributed by the lime juice. The garlic is optional; some recipes will suggest including or excluding it.
When using both garlic and chiles in the sauce, try pounding them together with a pinch of sugar in a mortar. This quickly releases their oils (helpful if you are in a hurry) and gives the sauce an appealing orange cast.
