The university researchers have been working with a coffee shop in Bath, England, called Colonna & Smalls in order to come up with best brew for the 2016 World Barista Championships. Through various experiments, it was found that chilling roasted beans before grinding led to a narrower distribution of small particles. For the brewing process this leads to more flavor being produced from the same amount of coffee. On hearing this, News18 (@CNNnews18) tweeted: “Chill your roasted coffee beans before you ground them for that perfect brew!”
For the study, the researchers examined what happens when beans are ground at different temperatures. This ranged from room temperature right down to minus 196°C. The studies were consistent: the colder the beans then the finer and more uniform the particles became as the beans were ground.
Commenting on the outcome, Dr Christopher Hendon, who led the study, told Laboratory Manager magazine: “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.”
He went onto explain: “We found that chilling the beans tightens up this process and can give higher extractions with less variance in the flavour.” This means that someone making chilled bean coffee only needs to brew the coffee for less time. In addition, more coffee can be extracted from the same number of beans.
The extraction depends on temperature, water chemistry and also the accessible surface area of the coffee. The most important factor, it seems, is temperature. In light of this, journalist Claire Hayhurst (@clairehayhurst) tweeted: “Chilling coffee beans before grinding is the secret to a more flavorful brew.”
This is because chilling affects particle size distributions, and this leads to quantifiable variations in the rate of extraction. Such variations are important, given that coffee is a valuable commodity and the intense competition between coffee shops for peoples’ custom. Moreover, recently the long-running U.S. Nurses’ Health Study found that coffee protects against type 2 diabetes and cardiovascular disease, so there are potential health benefits too.
Whether the developed coffee will wow consumers and coffee lovers remains to be seen. The World Barista Championships take place in Dublin and runs between 22-25 June, 2016.
The University of Bath research has been published in the journal Nature Scientific Reports, and it is headed “The effect of bean origin and temperature on grinding roasted coffee.”
