Provided is a powdered raw material, which is housed in a housing portion (12) of a type of a bottle cap 1 which has the housing portion (12) that houses the powdered raw material, and of which the housing portion (12) is opened by an uncapping operation, and then causes the raw material to be released into the bottle. Using a multi-functional powder property measuring instrument multi-tester, the powdered raw material is dropped onto a watch glass from a powder falling point, a dropped mass and a mass on the watch glass are measured, and a degree of dispersion which is obtained from the following formula (1) is equal to or more than 5% and equal to or lower than 40%. degree of dispersion%=dropped mass-mass on the watch glass/the dropped mass×100
