Later this month, all that practice will culminate in 15 minutes of head-to-head competition. But it won't be a typical sporting challenge - instead, Mr Douglas will be vying with other baristas at the unofficial coffee Olympics.

The World Barista Championship and World Brewers Cup, which this year take place in Melbourne, are the most prestigious competitions in the world of coffee, with just one or two entrants taking part per country.

Baristas dedicate countless hours to practice and bring support crews to look after their specialist equipment, while spectators fly in from across the world to watch the competition from a grandstand.

As the reigning Australian barista champion, Mr Douglas might be the hometown favourite, but he isn't taking anything for granted.

"It will be a very big deal for me, something I've worked towards for a very long time," Mr Douglas told AAP.

"It's seen as the ultimate level of achievement within the industry, in terms of your skill being recognised and then judged."

Around 50 people will take part in the World Barista Championship, which tests espresso-making skills, while 35 filter coffee brewers will compete for the World Brewers Cup.

Baristas have just 15 minutes to serve up one espresso, one milk drink and one inventive coffee concoction to each of the four judges in order to showcase the full range of their skills.

They must then describe the flavours of the coffee in detail to the panel.

Mr Douglas said differences in coffee flavour and texture came down to a range of factors, including the quality of beans, the roast, the ratio of water to coffee and a barista's experience.

"From the barista side of things, behind the machine, it's really understanding the variables involved and taking full control over them," he said.

Winners can find new doors opened to them, with many going on to start their own businesses - while one has been featured in a film.

"I know a lot of the competitors who will be competing, you know it's not their first rodeo. They've been on the world stage for a few years," Mr Douglas said.

"People who have won or come close to winning generally have a pretty big reputation."

The contest will take place during the Melbourne International Coffee Exhibition (MICE).

Up to 12,000 people usually attend the event and organisers are expecting the competitions to attract even more visitors this year.

MICE show director Lauren Winterbottom said organisers were expecting a large overseas contingent, which will include the competitors and their support teams.

"We have grandstand seating and big screens, it's all happening. It really is like a sporting event when you see it," she said.

The expo and championship will run from September 27-30 at the Melbourne Convention Centre.

Australian Associated Press