Disseminating the Fragrance of Coffee

Recently, I had the pleasure of being a participant in a study conducted by coffee guru Mario Fernandez, who’s studying a PhD on ‘Flavour Formation in Arabica Naturals’ at the University of Otago.

(Arabica is the species of coffee plant and ‘natural’ is a type of processing the coffee has gone through, performed at origin. Mario is looking at how different processing methods affects flavour in coffees.

In order to actually experience the different fragrances formed in the coffee, Mario managed to capture the fragrances of different coffees within a resin. Then using the machine pictured below, disseminate those individual chemicals responsible for smell and blow them out of the nozzle for the participant.

Take a moment to let this sink in: this is the fragrance of coffee, split into each individual chemical.

Mind = Blown.

Olfactometry machine

Sit and Sniff

As a participant I was to sit and sniff whatever came out of that nozzle for the session length of 31 minutes then measure the intensity and define the odour. I did this 12 times for 12 different coffees (different origins and processing methods) over two weeks.

The smells ranged from sweet, fruity, floral smells to pungent, musty, fermented smells and everything in between. We used a custom coffee Flavour Wheel to determine the smells. Some coffees had considerably more smells coming out than others, and there were some similarities between the coffees but not many.

Here are some learnings and observations about the experience as a participant:

  • It was rather tiring focusing on my sense of smell for such a long time. I guess we only tend to use this sense when there is something that alerts us to it. 30 minutes focusing on picking things up with your nose is harder than you’d think.
  • Many coffees had unpleasant individual odours coming through but as a whole coffee, would have been pleasant. I guess they’re present but are masked by nicer smells or they contribute a small part like instruments in a song.
  • There were smells that I completely missed and other participants got and vice versa – each of our noses has ‘olfactory blind spots’.

Miscellaneous scienceCoffee = Complex

To me, this experiment gave me a greater understanding of how complex coffee is. The chemicals that contribute to flavour and aroma are developed within the bean during the growing, ripening, processing and roasting of the coffee. At each of these stages, significant changes occur at a chemical level. As we develop our understanding of these aspects of coffee we gain the ability to alter the end result. Exciting.

Thanks Mario for the opportunity to be involved in such a cool project!

PS. I had a go at Natural Processing in Sumatra, Indonesia! It’s also called Honey Washing and it affects the sweetness, acidity and complexity of flavour. I only did it for 10 minutes

Honey Washing Coffee in Sumatra
Trying my hands at Honey Washing Coffee in Sumatra, March 2014

Read more about natural processing (via Stumptown Coffee Roasters)