THE art of roasting coffee may be on the way out. For centuries, experts have
used their judgement to decide when beans are ready to become a punchy espresso
or a smooth latte. Now a computer algorithm could put them out of a job.
Master roasters use the look, smell and taste of the beans as they cook, as
well as listening for 鈥渃rackings鈥� as gases inside the beans react and explode.
鈥淩oasting coffee is a difficult process with many variables,鈥� says Alfredo
Hern谩ndez from the Joint Research Unit for Food Process Engineering in
Massy, near Paris.
鈥淥nly the master roaster can say how long to roast and at what air
temperature for a specific kind of bean,鈥� Hern谩ndez explains. But now he
has developed a computer model that he claims can simplify the process.
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Consumers want plump, rich-coloured beans. So Hern谩ndez and his team
used cameras linked to a computer to take snapshots of roasting beans every 20
seconds. A neural network then analysed each picture and learned to predict
which roasting times and temperatures produced the best-looking beans.
Hern谩ndez hopes the results can be converted into simple colour and size
charts that less skilled operators can use.
But some coffee experts are worried. 鈥淲hat if the coffee doesn鈥檛 taste any
good?鈥� says Attilio Sciannimanica, a roaster from Cosmorex Coffee in Canberra.
Each batch of beans is different, he says, so roasting conditions that were
right last week could incinerate the beans the next.
