The boiled water (100oC) is introduced to the suitable temperature for that yeast to work as ten - 15oC. This temperature will depend on the kind of yeast and the type of beer. Saigon (also officially generally known as Ho Chi Minh Metropolis or domestically in Vietnamese as Sài Gòn) https://milomscba.suomiblog.com/not-known-facts-about-saigonlist-46030644