What liquid seasoning is added toward the end when making pho broth?

Fish sauce is the liquid seasoning added toward the end when making pho broth.

Vietnamese fish sauce, or nước mắm, is made by fermenting fish with salt. It contributes salt, savory depth, and umami without overwhelming the broth with the stronger aroma that prolonged boiling can produce. Cooks generally adjust the seasoning after the bones, aromatics, and spices have infused the stock.

Pho broth is typically built from bones, charred onion and ginger, and spices such as star anise, cinnamon, cloves, and coriander. Fish sauce is different from hoisin sauce: hoisin is usually a sweet table condiment, while fish sauce is a salty seasoning used during cooking or added to taste.

Recipes vary by region and household, and some cooks use additional salt, rock sugar, or monosodium glutamate. The key point is that fish sauce fine-tunes the finished broth rather than serving as its primary liquid base.