There are little brown beans here from Brazil, Bolivia, Ethiopia, Nicaragua, Honduras and Hawaii. The national barista championships are a broad church, united in worship of coffee, single-origin brews and skinny jeans.

By the espresso bar at the Melbourne Showgrounds, earnest congregations discuss the consistency of cappuccino foam. Backstage, under a big white tent, the best baristas in Australia measure out their lives with polished coffee spoons.

Perth's Ronald Ngo, tall with a shock of green in his high black hair, compares such competitions to a choreographed dance: each move must have a purpose, every step a design. It sounds beautiful, I say. "I have vomited," he confesses. "The pressure gets too much and your stomach gets queasy."

He looks around at his fellow competitors: one scoffs a banana to block stress hormones; Sydney's Hazel de los Reyes, from Coffee Alchemy in Marrickville, holds out her hands to check them for shaking. Some baristas have been known to sneak shots from hip flasks to steady their nerves. "This isn't just a hobby for any of us. You put your life and career into one cup of coffee," Ngo says.

Adding to the pressure this year is the prospect of competing at home in the world barista championships, which will be held in Melbourne in May.

"Some people have been sick with the stress; they shake uncontrollably or just run around aimlessly," local lad Matt Perger says. "My heart rate doesn't exceed 60 beats per minute. I am generally pretty stress-free and methodical. "

Turn on the love

Matt Perger, 22, struts about the showgrounds, which is no mean feat in skin-tight black jeans. The effect of such studied nonchalance is spoilt somewhat by his several trips to the toilet.

Perger's employer St Ali, of South Melbourne, has flown in professional coffee taster Ben Kaminsky from San Francisco as his coach. Together, they have been tasting upwards of 80 coffees a day, experimenting late into the night with grinders, fat content in milk and tamping techniques. St Ali co-owner Ross Quail reckons that for every hour of work over the past two months, Perger has spent six more training for this competition. Perger is a "coffee professional", Quail says. "His role is to rediscover the truth."

To be the best barista you must "catch a coffee in one moment, be perfect for 15 minutes", Quail says. The night before the national heats, he critiques Perger's performance. "You're lacking a little bit of emotion. Turn on the love, boy," he says. "I can do that," Perger replies.

The next morning there is a queue for piccolo lattes at the showground's free coffee bar. First on stage are competitors from three chain coffee stores. Maddisson Whitechurch, from a Gloria Jeans franchise in Fremantle, dedicates her performance to her late father. "I can taste a little bit of dad in this coffee," she says.

Sarah Do, 19, from Krispy Kreme, tells the judges her signature drink was inspired by the store's slogan: "Coffee and donuts since 1937." But the winner is Muffin Break's Michael Byrne, who announces he is contemplating leaving the coffee game for professional weightlifting.

12 drinks in 15 minutes

The rules of the World Barista Championship or WBC (not to be confused with the World Boxing Council) fill 20 pages of small font. Competitors must make 12 drinks in 15 minutes: four espressos, four cappuccinos and four creative "signature drinks". Baristas must explain the flavour notes and "mouth feel" of their coffees to seven judges with clipboards, who pore over their every move.

The greatest weight of points is awarded for flavour. But the best barista might be undone on technicalities. In an upstairs room, the judges take points from some competitors for wrinkled aprons or "poor sanitary practices". One entrant scores low for creativity in his signature drink. "I thought the flavour overall was pretty generic," a judge says. "I mean coffee and chocolate? Whoop di doo."

The complexity of judging the black brew is lost on the average cafe-goer. Kaminsky compares barista competitions to dog shows. "You watch judges look at carefully primped dogs, trainers who have spent years with their dogs to train them to be perfect examples of their breed," he says.

The best competition baristas agonise over every detail, from the shine on their water glasses to their choice of backing tracks. "Generally you're looking for songs that are upbeat. If you're tasting coffee while listening to a sad song it is probably not going to taste as good," Perger says. "Anything can sway the scores: the music, my table settings, my clothes. If I was ugly, my scores would probably be lower as well. If I had a hunchback, they would probably not like my espressos as much."

To be fair, the WBC rules contain no prescriptions on whether a barista is easy on the eye. They do, though, formally "encourage audience participation and enthusiastic fan support". But it was a small crowd in the stands for last weekend's championship, well below the expected audience of 10,000 across the three-day competition.

The finals on days two and three draw a slightly larger reception, including comedian Ben Lomas, who is mining material for a comedy festival routine on Melbourne's coffee culture. "Coffee has become an accessory - when did that happen?," he says.

Lively competition in the coffee tasting and latte art competitions stirs the most applause. Several baristas making latte art are almost undone by nervous, shaking hands. Some people in the crowd find their avant-garde creations equally challenging, among them milk foam depictions of Batman, a redback spider and a perplexing "peacock on fire".

Coffee is bad for the nerves

Four of the six competitors in Sunday morning's barista finals are former national champions. Among them is de los Reyes, who has been awake with nerves since 4am. Two months out from the championship, after winning the NSW finals, she suffered a crisis of confidence. Surrounded by sticky, sickly green and red and orange concoctions, lightly roasted coffee beans and dirty cups, she sat on her roastery floor and stayed there for two hours. "Nothing's working, nothing's yummy, nothing is tasting right, everything is disgusting," she thought at the time. "I sat there thinking 'I have nothing. Nothing'."

She once battled writer's block similarly while crafting a fantasy book about coffee trees, like the ones that grew in her grandmother's backyard in the Philippines. "I guess coffee happens regardless of whether I will it or not. Even if I don't want to think about coffee, I think about it all the time," she says.

Finally, she settled on a routine that incorporated a hazelnut and cherry fizz creation, as tribute to her Bolivian beans and their soft-drink-loving coffee farmer. Winning the national title in 2005 helped her business and reputation, she says. "I needed to make coffee a viable, profitable business for myself, so competition was one way of getting recognition. We had had quite a lot of comments that 'this is the best coffee I have ever had that's been made by an Asian'. So competition was one way of being taken seriously. "

Stallone versus Lundgren

There are two types of baristas, I am told: instinctive talents, such as de los Reyes, and precise, scientific wunderkinds, such as Perger. In celluloid terms, it's like Sylvester Stallone fighting Dolph Lundgren in Rocky IV, except with frothy milk in place of fists.

Victorian competitor Craig Simon, the 2012 national champion, puts himself in the former category. He prepares for competition by visualizing his entire routine, a skill he learnt while touring with bands as a drummer. "You see yourself and hear yourself doing it perfectly without limitations," he says.

"I will do my routine in my brain, that way I can practise before I go to bed, in the middle of the day, on the train. I can practise all the time."

For several months he has been playing out his coffee routine in his head, then checking his heart rate to make sure it stays stable. Ahead of his final performance on Sunday, he is alone backstage. He walks in circles for the full 15 minutes, mumbling to himself.

Two-time national champion David Makin, a fellow Melburnian, of Axil Coffee Roasters, in Hawthorn, says at this stage of the competition it is a mental game. "The final is not about making the best coffee, it's about who the judges want to send to the world championships. If you come across as f--king arrogant, it will count against you - they've got to like you."

He distinguishes between competition baristas and cafe baristas. "Just because you can get up and present 12 coffees in 15 minutes doesn't mean you can be put into a cafe that does 1000 cups of coffee a day, or doesn't mean you are good at remembering customers' names."

Perger has not pulled a coffee for a customer for more than a month. Before he performs, his girlfriend hands out "Team Perger" sweatshirts and caps to his supporters in the crowd. Kaminsky hugs him and whispers in his ear: "This is the future of speciality coffee."

What follows is an almost faultless routine based around novel methods for grinding beans and for using the espresso machine. As part of his signature drink, Perger uses an eye dropper to pipe mascerated plum onto teaspoons, which he then caramelises with a blowtorch. The judges are impressed and award Perger the national title. He "captured the best of the coffee and brought it out in the cup", head judge Saxon Wright says.

"It's a lot of elbow grease, a lot of hours," Perger says. ''For the nationals, it is three months after hours in the training room until 11pm, doing run throughs, tasting the coffee. It feels insurmountable at the start once you know what it takes."

Being the best requires no less than taking a customer who has popped in for a humble latte and having them leave inspired, he says. "You are trying to create an experience for them. You are trying to show them you have customer service, you have passion.

"You need to ask yourself if they were in a cafe with you, would they walk away inspired?"

And then he walks away, too. It's time to start training for the world championships in May.