Desperate for a good cup of coffee? Chill your beans, say scientists
Brewing a more flavoursome cup of coffee could be as simple as chilling the beans before grinding, scientists say.
A team from the University of Bath found that the colder the beans, the finer and more uniform the particles were from the grind.
The narrower distribution of particles allowed access to more flavour from the same amount of coffee during the brewing process.
Experts from the university worked with coffee shop Colonna & Smalls in Bath, Somerset, to examine the effect of grinding beans at different temperatures.
In the study, highlighted in Nature and published in Scientific Reports, the team tested the beans from room temperature to minus 196 C.
The finer and more uniform particles from colder beans resulted in better extraction of the flavour compounds - meaning more coffee and flavour.
Dr Christopher Hendon, a chemistry PhD student at the University of Bath at the time of the study, said: "What you're looking for is a grind that has the smallest difference between the smallest and largest particle.
"If you have small grinds you can push flavour extraction upwards.
"We found that chilling the beans tightens up this process and can give higher extractions with less variance in the flavour - so you would have to brew it for less time, or could get more coffee from the same beans."
Dr Hendon, now working at the Massachusetts Institute of Technology, added: "It will alter the taste, because subtle changes in particle size distributions make a huge difference in rate of extraction.
"I wouldn't be surprised if people struggled to achieve balanced extractions.
"It could have a major impact for the industry. People are trying to produce a very high quality drink with really quite powerful tools and are willing to try new things."
The research took place in the lead up to the World Barista Championships, which take place in Dublin this month.
Coffee is among the most valuable traded commodities globally, worth 17.9 trillion dollars (£12.6 trillion) to the US economy in 2015 alone.
A spokesman for the University of Bath said: "This discovery could have big implications for the coffee industry and might even allow domestic coffee connoisseurs to brew tastier beverages."
Maxwell Colonna-Dashwood, co-owner of Colonna & Smalls, said the subtleties of processing coffee have a "huge impact on the flavour and quality".
"The ability to understand grinding more comprehensively has the dual impact of allowing us to make better tasting coffee and to be more efficient in the way we do that," he said.
"The research suggests that temperature of bean needs to be more constant to help us achieve consistent grinds.
"It suggests that cooler temperatures will allow us to maximise surface area and utilise more of the coffee.
"All of this will impact on how we prepare coffee in the industry, I bet we will see the impact of this paper in coffee competitions around the globe, but also in the research and development of new grinding technology for the market place."