Coffee? One fungus or two?
Fungi are the secret to tasty coffee, says a Brazilian researcher who is the first to identify the moulds that give coffee its distinctive range of flavours and aromas.
Taniwaki says while the characteristics of the bean partly determine taste and aroma, naturally occurring fungi also put the zing in your favourite brew.
"We are doing a project to correlate the presence of certain species of fungi in coffee with coffee flavour," she says.
The research team collected raw coffee beans from farms in Sao Paulo and Minas Gerais in Brazil, disinfected them, incubated them for seven days, and isolated the fungi.
Then the team got down to the pleasant part of the experiment. They roasted, ground, brewed and drank the raw samples, rating them for body, aroma, acidity, bitterness, astringency and sweetness.
Some of the flavours associated with moulds included floral, citric, caramel, chocolate and toast.
The fungi occur naturally inside the coffee been and are associated with regional characteristics caused by soil, climate and humidity.
While the pleasant taste-producing fungi are not harmful to health, others can be toxic, and these often produce rancid, stinky, smoky, woody or fermented bouquets.
Tanawaki says her research is currently focused on isolating the various fungi and how they are metabolised.
But it may be possible to use the knowledge to produce ranges of coffee with a particular flavour, potentially complementing the traditional bottles of vanilla or hazelnut flavourings found at your local cafe.
"We can encourage the good fungi to grow and use it to produce good flavours, like wine or other food like cheese where you use mould or yeast to ... give a special flavour," she says.
Professor Paul Gadek, an Australian plant molecular biologist and head of tropical plant sciences at James Cook University, says Taniwaki's research has implications for Australia, where coffee is a growth industry.
He says it would be interesting to find out which species of fungi are found in Australian coffee beans.
"What are the characteristics that we can grow regionally to generate distinctive flavours?"