When Professor Wilson Poon visited a ceramics factory you could say he had a moment of sweet inspiration.
He recalls the pleasure of looking into the mix of clay and liquid and thinking, “I’ve seen that before.”
Professor Poon, from the School of Physics and Astronomy at the University of Edinburgh, found himself visiting this ceramics factory as part of research involving the smoothness of chocolate.
The visit confirmed to the self-professed expert in “goo” that clay behaved something like a thick, free-flowing powdered chocolate mix. And that helped him on his way to understanding how it might be possible to reduce the fat content in chocolate.
“When we talk about lower fat, we are talking about lower oil and that ultimately means lower liquid, but still maintaining its flow,” says Professor Poon.
So, for chocolate manufacture, adding as little liquid means adding less oil and lowering the fat content of the chocolate. The popularity of such a product is obvious but the experience of placing a square of chocolate on the tongue would still need to remain as pleasurable.
“I know nothing about flavours and chemistry and biology, but in terms of physics I do know that ‘mouth feel’ is important. 
“When it melts, it needs to be molten, and not gritty,” he says.
What led him to the ceramics factory was something of an accident. At a conference he met a scientist from the famous confectionery manufacturer, Mars. “At that point I had just invented a piece of apparatus that this particular scientist was interested in. When I say my background is in goo, what I mean is any liquid that has bits in it. Examples of that would be a pot of paint or toothpaste.”
As Professor Poon explains, this ‘goo’ needs to have movement. It needs to be squirted through a tube or in the case of something like concrete, flow through a pipe.
“The piece of apparatus allowed pictures to be taken of what those bits are doing when the goo flows. It gives unprecedented detail and that was something that Mars was 
interested in.”
The company was interested enough to co-fund a study with the Engineering and Physical Sciences Research Council, where Professor Poon and his colleagues collaborated with researchers from New York University. 
The study results were published recently in the Proceedings of the National Academy of Sciences. Mars’s interest dates back to 1879, when Rodolphe Lindt developed what is known as the “conching” process, something that transforms chocolate from being gritty and bitty into the smooth treat that we know and love today.
Why would Mars be interested in seeing what happens in chocolate manufacture in such detail? 
Surely the company had perfected the process? 
The professor explains: “Manufacturers know how to conch – in engineering sometimes the understanding of how something works is not as important as the 
“They would say conching is like spreading butter on toast, describing the process of spreading the cocoa fat over the sugar grains.
“But then my reaction would be ‘how do you know?’ That takes absolutely nothing away from engineers – for example, they can make bridges work even though they don’t know how concrete sets. So when it comes to how conching works, Mars came to us and said they wanted to understand the physics. 
“I believe that our study is practically the first to go into those details.”
The details can be applied across many industries where processes involve suspending particles in liquid. For chocolate, Professor Poon has been working on it in its molten state – at the point of manufacture in the factory. 
The analysis involved measuring the density of mixtures and how they flow at various stages of the process. It suggested that conching may alter the physical properties of the microscopic sugar crystals and other granular ingredients of chocolate.
Another aspect of the study could be helpful towards creating greener manufacturing in confectionery and other products with similar manufacturing processes. Professor Poon says reducing the amount of heat required could be a key.
“We have certainly managed to calculate the types of energy that could be needed, but it is early days.”
None of this may make a difference to the enjoyment that chocoholics get from their treat but it shows how science and industry can work together to make improvements that could benefit our health and the planet.