Wine and broth have a double function: they provide liquid with which to conduct the cooking and they add flavor. No more wine or broth should be used than is necessary to fulfill the flavoring portion of their roles. It is quite possible that the quantity indicated by the recipe is not sufficient to last to the end of the cooking time. In such cases one adds water because it is neutral in flavor. If one were to add wine it might add sourness to the dish or load it with astringency. If one were to add broth it might make it too salty, or simply overemphasize the brothβs flavor.