Here's how to brew that perfect coffee

In a prefect combination of technology and tradition, James Freeman, in a small cafe in San Francisco is proving that there's no such thing as too technical when it comes to making the perfect coffee.

In his Blue Bottle Cafe on Mint St, the counter is dominated by a couple of contraptions that would look more at home in a mad scientists' laboratory, but which actually represent a San Franciscan pursuit for perfect coffee.

The New York Times has put the price of Freeman's dedication to perfect coffee at $20,000 and that's just for one of the machines.

"The $20,000 was basically the machine, the sourcing the beans, the labour - they got it up to that figure," the Courier Mail quoted him as saying.

"But they're all pretty expensive, I can say that much," added Freeman.

His favourite is the copper-clad lever espresso machine, a vintage Italian job from the 1970s.

But for perfect coffee, he says no one does it like the Japanese.

To prove it, two years ago, Freeman sourced a pair of Oji drip-fed machines from Japan.

The Oji machines fuse tradition and tech in a way that might seem ridiculous to non-coffee drinkers, but those queued around the block outside his Blue Bottle Cafe in Mint St give thanks for it twice a day as it takes 12 hours to make a potl.

Each pot starts with 3.2 litres of water in the top globe, which releases exactly 88 drips per minute through a glass cylinder holding 160g of coffee.

The coffee is "single source" - all the beans are from the same crop, not blended - and coupled with the fact there's only six litres of it available every 12 hours, chances are that might all add up for the world's most expensive hangover cure.

"It's 4 dollar for a 12-ounce glass of ice coffee," said Freeman.

"It's a wonderful iced coffee, kind of a bourbon-like iced coffee. It's got a heat to it that's like having a shot of bourbon," he added.

Then there's the other Oji - the "$20,000" one that makes hot coffee.

Water is heated in each globe by halogen lights, which forces it up into a module holding the coffee grounds.

The mixture is stirred with a bamboo paddle in a manner, which has to be perfected by baristas before they get to lay a hand on Freeman's machine.

The "art" is creating a whirlpool within four turns something that Freeman said he spent months practicing.

Stir it too much (more than 90 seconds) and the coffee over-extracts. Too little (less than 45 seconds) and your coffee is underdone.

The mix is then filtered back down into another globe and kept at that temperature by a barista cradling it with a moist cloth.

Although he calls his vintage lever machine his "rosebud", Freeman said he prefers the routine of making siphon coffee in the morning.

"It's a very nuanced technique," he said.