Bass Rosin helps create friction and when applied to bow hair, allows the bow to grip the double bass strings and make them vibrate more clearly and with more control. If a bass bow does not slide easily, and produces no sound or only a faint, thin sound, then the bow hair does not have enough rosin.
Bass Rosin is made by heating resin, a sticky substance tapped off from certain trees - usually pines, firs, larches or spruces. Each rosin maker has a special formula for their mixture. When the resin melts or liquifies, it is strained, purified and poured into molds for cooling. It is then smoothed, polished and fitted into containers.