In the seventeenth century ice cream was made in a closed tin box that was left to freeze, producing a solid ice cream. By the mid-eighteenth century the ice-cream mixture was frozen by pouring it into a pewter canister with a handled lid called a sorbetière. The sorbetière was placed in a wooden bucket containing a mixture of ice and salt, or saltpetre. The right ratio of salt to ice would prevent the ice from melting. The ice-cream mixture was then turned by the handle of the sorbetière to mix and an ice spaddle or houlette was used to scrape down the frozen mixture from the sides and into the rest of the soon-to-be ice cream.