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How Coffee Bean Origin and Grinding Temperature effect Particle Size

Science does not always have to be tough and exacting. Sometimes it involves freezing ice cream, brewing beer and even making coffee. One group of researchers took a scientific coffee drinker’s interest in coffee bean quality and grinding one step further and ended up writing a paper about the results for the prestigious journal NATURE.

Unless you are a habitual user of what is known as ‘instant coffee’, you will probably have a particular favourite type of coffee, defined by origin, roast and type of grind (which then influences how the coffee is best made). As flavour is a subjective measure it has not been easy to get empirical data on how different factors effect the preparation of a cup of coffee.

We do know that coffee is prepared by extracting a wide range of complex organic molecules e.g. aromatic oils such as caffeol, from the roasted ‘brown’ bean. The roasting process, which is not necessarily even the first processing step, involves the Maillard reaction. This is the same reaction between amino acids and reducing sugars that makes browned food so delicious.

Seared meats, biscuits, ‘brown’ crusty bread and even toasted marshmallows all owe their popularity to the Maillard reaction. To extract the maximum flavour the beans must be ground into fine particles. It is not surprising then that coffee quality depends on temperature, water chemistry and the surface area of coffee accessible to the water.

In a recent NATURE paper researchers investigated whether variations in the production processes of coffee beans (single origin) effects the particle size distribution after grinding as measured by laser diffraction particle size analysis.

Interestingly it was found that the particle size distribution was independent of both the bean origin and the processing method. However, the bean temperature on grinding did influence particle size distribution. Grinding from cold resulted in reduced mean particle size and a narrower particle size distribution.

These results might well influence the production of coffee industrially, and how coffee is stored and used on a daily basis. Scientists, dedicated to making your life better, one cup of coffee at a time.

to find out more about the instruments used please click here.

Date added: 2016-07-05 12:22:53