Cold coffee beans deliver more flavour

Scientists say brewing more flavoursome coffee could be as simple as chilling the beans before grinding.

A team from the University of Bath, working with Bath coffee shop Colonna & Smalls, found that chilling roasted beans before grinding resulted in narrower distribution of small particles, which, during the brewing process, allows access to more flavour from the same amount of coffee.

Coffee is among the most valuable traded commodities globally, so the discovery could have big implications for the coffee industry as well as allowing coffee connoisseurs to brew tastier beverages.

The team studied the effect of grinding beans at different temperatures, from room temperature to -196°C, and discovered that the colder the beans, the finer and more uniform the particles were from the grind.

Small, uniform coffee grinds allow for better extraction of the flavour compounds — allowing users to brew more coffee and get more flavour.

“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,” said researcher Dr Christopher Hendon.

“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.”

Maxwell Colonna-Dashwood, co-owner of Colonna & Smalls, said: “Grinding coffee may seem quite straightforward — break coffee up into a lot of tiny bits so you can dissolve it in water. But like the whole world of coffee, the subtleties of the process have a huge impact on the flavour and quality of the cup of coffee. 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.

“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 [not only] in coffee competitions around the globe, but also in the research and development of new grinding technology for the marketplace.”

The study is published in Nature.