The Chaicoffski is, according to its Australian inventor, Ian Bersten, a simple, quick and economical way to make coffee.
It's based on the idea that extraction depends on particle size, not brew time, as many people in the coffee industry believe, says Mr Bersten.
"The instructions for most plungers say to use coarse or medium grind coffee," he says. "I started to experiment with espresso grind. I poured boiling water over espresso grind coffee in a plunger, without pushing the plunger down.
"I was getting tremendous strength, and no matter how long I left the coffee in the plunger, it never got bitter," says Mr Bersten, who founded Sydney coffee roaster Belaroma in 1968.
"This defied all knowledge of coffee brewing: that you had to control the time to prevent bitterness. You can prove it for yourself by pouring boiling water over the finest ground coffee in a glass and letting it stand. It will never get bitter. But if you apply additional heat to brewed coffee it will become bitter."
The idea that brew time causes bitterness comes from making coffee in percolators, he says – the continual reheating is the problem, not the time. "I came to the idea that a percolator was literally a saucepan of boiling water on the stove and you were dropping a basket of coffee into it every five seconds."
The Chaicoffski is simple, if high-tech in conception – a 60-micron cup-shaped stainless-steel filter, and a matching double-walled mug. You put espresso grind coffee in the filter and add boiling water. The fine mesh stops the water passing straight through and creates turbulence in the mug; that, and the fine grind, allow rapid extraction, says Mr Bersten.
After 30 seconds you lift the filter out, rest it on the side of the mug to drain, and voila! – a very quick cup of plunger-style coffee, best left to cool before drinking.
Mr Bersten points out that using espresso-grind means you need much less coffee: about 40 grams per litre of water rather than the 60 grams usually recommended.
"I thought that was a great plus for the consumer," he says. But from a marketing point of view, that has turned out to be the Chaicoffski's weakness: "Coffee roasters said, 'I'm not going to sell a machine that reduces the sale of coffee beans'."