Eureka! Greeks discover recipe for perfect chips

Scientists have worked out six equations to prove that the perfect potato chip should be cooked for a minute in the microwave before it is plunged into a fryer of refined oil at an averagely hot temperature.

The team of scientists, led by Mazda Krokida at the National Technical University of Athens, in Greece, has shown that many people are still using the wrong method to cook their chips.

The equations describe the physical and chemical changes that occur when a batch of raw potato chips is plunged into a commercial deep-fat fryer.

Three of them concern moisture loss, a subject dear to the chip connoisseur because the perfect chip is neither too wet nor too dry. The other three are concern the fat absorption, equally dear to the connoisseur gazing into a mirror (who, like the best chips, would ideally be neither too thin nor too fat).

According to New Scientist magazine, which reports the work today, two of the equations deserve special attention. The first says the final moisture content after cooking depends principally on the starting moisture content, which decreases exponentially with time and temperature.

The second says that the fat content of the cooked chip also depends on the initial content and that the exponential relationship between fat uptake and temperature means that the ideal temperature is not too high. In simple terms, the equations make two main points; a fatter chip, which contains more moisture, takes longer to cook but heating up the oil - to make it cook faster - results in more fat being absorbed.

By cooking the raw potato chip in a microwave for a minute first, to drive off moisture, the chips can be cooked at the medium temperature that prevents too much fat uptake.

Dr Krokida and her team, who spent a year studying what affected a chip's final composition, told the magazine: "The main reason for doing this is for health reasons, to find ways of reducing the oil content of chips." But she added that there was no equation for the ideal thickness of chips which "should be a matter of taste".

A spokesman for McDonald's said it fried potatoes cut to length for three minutes in high-temperature fryers: "We haven't heard of this method. But we're serving about 2.5 million customers a day in Britain and most of them have fries. And they seem happy."