Baristas expect oat milk to be the next coffee craze after new data suggested Australia is split over whether the latte, cappuccino or flat white is best.
The national data released on Wednesday from payment platform Square says the humble latte made up one in every three orders (33 per cent) in 2018.
But that's lower than two years ago when it was ordered 43 per cent of the time.
And while the latte, cappuccino and flat white still make up about three-in-four orders, the states and territories are split on the best way to get a caffeine hit.
Lattes remain strong in Victoria (42 per cent) and Tasmania (32 per cent) while flat white tops menus in Queensland (26 per cent), Western Australia (37 per cent), ACT (39 per cent) and Northern Territory (29 per cent).
NSW - often derided by Victoria for having an apparently weaker coffee culture - have a more varied taste with cappuccino the leading coffee at 26 per cent.
But the biggest change in 2019 will be what people put into their coffee rather than the way they have it, Melbourne cafe Proud Mary general manager Tom Gunn says.
"Oat milk will be huge," he told AAP.
"We have another cafe in America and oat milk has completely dominated the market there - completely destroyed almond milk and soy is now minimal."
He said compared to other dairy milk alternatives, oat milk tastes better, matches coffee better, froths more easily and importantly has funding behind it from large US companies.
Pippa Ainsworth, the owner of the Darwin cafe The Trader, said she was surprised Australia was behind on the craze on what she sees a yummy, environmentally sustainable option.
"I was just in London and oat milk was in every cafe - no question," she told AAP.
But Ms Ainsworth says people are fickle about their brew, and often chase the next craze.
"We serve a lot of tradies and Defence personnel and the weirdest thing is the Defence forces all have the same order.
"It may change every few weeks, from cappuccino to hazelnut latte - but they'll all change together."
"We tease them about it."
The Square coffee data is based on millions of orders made through Square point-of-sale devices.
