After a blind tasting of six different coffees – from Brazil, Cameroon (robusta), Colombia, Costa Rica, Ivory Coast (robusta), and Kenya – among a group of French consumers, the International Coffee Organization found that:
Colombian coffee was rated as having the strongest aroma; it was rated significantly higher than Costa Rican, Cameroonian, Brazilian, and Kenyan. Only coffee from the Ivory Coast was higher for some tasters.
Acidity was a difficult characteristic for the tasters to assess. Costa Rican and Colombian coffees were found to have the most acidity. Very dark-roast coffees tend to lose almost all their acidity, unlike light-roast coffees, which develop high acidity.
Kenyan coffee was perceived to be significantly less bitter than Colombian, Costa Rican, and Brazilian coffees, although the latter were dark roasted and somewhat bitter, but no less bitter than the two robusta coffees. (A dark roast increases bitterness more in arabica than in robusta coffee, but Kenyan beans are the exception that proves this general rule.)
A fruity flavour, which might be expected to disappear with a very dark roast, was still identified by the tasters, and Kenyan coffee was perceived as being markedly more fruity than the two robustas, but not significantly more fruity than the Brazilian, Colombian, and Costa Rican coffees.
When the tasters were asked to identify burnt flavours, the results were similar to the tasting for bitterness. The participants could be divided into two groups – those who could distinguish the burnt characteristics and those who could not. Both Costa Rican and Colombian coffees were, however, perceived as having a noticeably greater degree of burnt aroma, or flavour, than the Kenyan coffee.
When it came to assessing body, Costa Rican coffee was found to be the most full bodied – the difference was most notable when the coffee was compared with the coffees from Kenya, Brazil, Ivory Coast, and Cameroon, although it was less marked when compared with Colombian coffee.
On average, all the coffees were regarded as having an aftertaste of medium intensity, with the Costa Rican coffee scoring significantly higher than all three of the coffees from Africa.
In general, the tasters expressed a preference for Kenyan coffee over those from Brazil, Colombia, and Ivory Coast, with the other two coffees coming second after the Kenyan coffee.
This tasting shows that, at least among this group of French consumers, the preferred coffee was the one that had the lowest intensities of aroma and bitterness, the lowest intensity of burnt and full-bodied characteristics, and a high degree of fruitiness. Colombian coffee, which has markedly different characteristics to Kenyan coffee, was significantly less liked than the African bean, and although the robusta from Cameroon was very close in perception to the Kenyan coffee, it was perceived as being more bitter and definitely less fruity.