First modern ice-cream maker

From ancient times, frozen ices and creams have been enjoyed by those wealthy enough to afford the laborious means of producing them. In the mid-19th century, ice cream finally became affordable to the masses, thanks to an ingenious hand-cranked machine invented by Philadelphian Nancy Johnson (USA) in 1843; she filed a patent for her "artificial freezer" on 29 July 1843 and it was granted on 9 September of the same year. Unlike in earlier models, Johnson’s ice-cream maker didn’t have to be constantly opened for a person to manually stir — instead, an interior dasher churned the contents while a crank rotated the canister in a wooden tub, producing a uniformly smooth and creamy ice cream. Although since automated and powered by electricity, removing virtually all manual labour from the churning process, the basic concept behind this design remains an integral part of all ice-cream-making apparatus today.

Emperors and other elites prized ice and snow for their cooling properties, but the icehouses they constructed could be used only for storage, not for harnessing ice’s power to chill other substances. Only in mid-16th-century Italy did scientists discover that potassium nitrate (saltpeter) would produce an icy cold liquid when added to water. The Italians began making flavoured ices, and the French followed suit. It was soon discovered that plain salt worked as well as saltpeter. A rudimentary freezing pot, a canister known as a sorbetière, was placed in a large wooden tub filled with ice and salt and then rotated to churn the contents of the pot. But these pots were awkward to use, since they had to be opened periodically to stir the freezing mixture inside to ensure that ice crystals didn’t develop.

In January 1844, just shortly after Nancy Johnson filed her patent in the USA, in the UK, London confectioner Thomas Masters patented an ice-cream maker that produced not only a creamy confection but also its own artificial ice.

By 1848, New Jersey inventor Eber C Seaman had scaled up Nancy Johnson’s basic hand-cranked model into a machine that could produce ice cream on a commercial scale, which lowered the cost of production and helped make ice cream the popular treat it remains today.