Now the "yerba" may be brewed. If the "bombilla" was inserted into dry "yerba", the mate must first be filled once with warm water as above, then be allowed to absorb it completely (which generally takes no more than two or three minutes). Treating the "yerba" with cool water before the addition of hot water is essential, as it protects the herb from being scalded and from the chemical breakdown of some of its desirable nutrients. Hot water may then be added by carefully pouring it, as with the cool water before, into the cavity opposite the "yerba", until it reaches almost to the top of the gourd when the "yerba" is fully saturated. Care should be taken to maintain the dryness of the swollen top of the "yerba" beside the edge of the gourd's opening.