The history of milkshakes: did you know they used to have eggs in them?

No one person can lay claim to inventing milkshakes: they evolved out of earlier drinks thanks to the modern mechanisation of the kitchen. But one US city can lay claim to them, the Atlanta Constitution did just that in 1886 - the year that Johannesburg was founded.

In the first printed reference to milkshakes, it describes a shaken drink of crushed ice and sweetened milk: "The newest Atlanta drink is 'milk shake'. You get it at the soda fountain. The mixer of cooling beverages pours out a glass of sweet milk, puts in a big spoonful of crushed ice, puts in a mixture of unknown ingredients, draws a bit of any desired sirup [sic], shakes the mixture in a tin can, like a barkeeper mixes lemonade, sprinkles a little nutmeg on the foaming milk until it looks something like a Tom and Jerry [an eggnog drink], sits it out for you and you pay five cents. 'Milk shake' is an Atlanta drink. Atlanta is nothing if not original."

Modern milkshakes developed from those early iced drinks, adding ice cream only after its production became more industrial with the electric fridge.

Ice cream is of course much older, possibly copied from China by Italians, just as they copied noodles.

George Washington had a "cream machine for making ice", so did Thomas Jefferson. In the early 19th century president James Maddison's wife Dolly served White House guests "a large, shining dome of pink ice cream" piled high on a silver platter.

In 1846 one Nancy Johnson invented the hand-cranking freezer to make ice cream: a wooden bucket of ice and salt in which a tub was placed with a paddle to churn it. More people could make it in home kitchens, but it was probably still too rare to melt into a glass of milk.

Before ice cream, milkshakes were alcoholic eggnog drinks made with whisky, eggs and milk.

But the modern version owes an equal debt to the Chicago area and the malted drink Horlicks - evaporated milk, malted barley and wheat powder as invented by William Horlick in Wisconsin in 1897 as a health drink for children and the infirm. People soon added chocolate syrup to jazz it up as a popular drink.

Polish immigrant Stephen Poplawski was commissioned to develop an automatic malt milk mixer, and came up with the modern blender in 1922.

The electric blender became key in whipping up milkshakes with ice cream, milk and a flavoured syrup at home. That created the modern version of shakes. (In 1911 Hamilton Beach had invented the first drink mixer for soda shops, but they were only used in soda shops, not at home.)

In the same year, a Chicago drugstore, Walgreens, came up with a milkshake with malted milk and ice cream, and in the 1930s freon-cooled fridges were invented, leading to machines that could make many shakes at once, made with soft-serve ice cream.

Milkshakes became a favourite in US drugstores, soda fountains, roadhouses and drive-throughs. They were made under many names and came in endless flavours: "frosted" drinks, frappes, velvets, cabinets or "concrete" for very thick drinks.

Today there are "crazy shakes", topped with whipped cream, ice cream and sweets, and "freak shakes", with the old "double-thick" long forgotten.

Freak shakes were created in 2016 by Anna Petridis at her Patissez Cafe in Canberra, Australia. It was an experiment of shakes topped by piled ice cream, with pastries or biscuits, deliberately made so attractive that people would photograph them with their cellphones. It worked, and they are now copied everywhere.

Bendable straws were invented in the 1930s to slurp up shakes too thick to drink, so therein lies the test: if you can drink it, it's a milkshake. If you need a spoon, maybe it has strayed into the field of desserts.

But then, milkshakes have spent more than 100 years straying from the original.