Why can I refuse wine when it is corked, but I have to pay a corked coffee?

by Luigi Odello

Secretary General of the International Institute of Coffee Tasters, he is also a lecturer at the University of Udine, Verona and at the Cattolica in Piacenza. In addition he is the Chairman of the Taster Study Center and Secretary General of the Italian Espresso National Institute

There is a strange combination in the chemicals of foods, which can be very useful to understand how the coffee industry is less mature than that of wine.
Both drinks contain the trichloroanisole (and their companions), perceptible at the level of one part per trillion (threshold of perception in the air, in coffee and wine is a little higher), which is seen by our sensory system as a threat and then declined in the most categorical way.
In fact, even a suburbs medium-level restaurant refuses to replace a bottle of wine to a customer if it is corked, while for coffee, people close their nose and drink. Yet from a data base we have been filling for years we understand that a significant amount of coffee on the market has trichloroanisole concentrations well above the threshold of perception, even 500 times. Yet they continue to circulate without limits.  
However, if we go on talking about defects we can consider geosmin’s smell of rotten wood and earth, pyrazine that gives a vegetable taste (pea, chicory, depending on what accompanies it and on the levels of presence), dimetilsulfide and dimetildisulfide, both donors of fetid scents, or the more calm vinylguaiacol that, when highly concentrated, confers smoke and burnt taste.
These are just some examples, because in the course about the defects in the coffee, which the International Institute of Coffee Tasters is developing, the tasters will have the opportunity to try about twenty, spending an unforgettable day. It is necessary to make this step to create an embankment to the product of poor quality circulating unpunished on the market to accurately identify and tell the barista that he can drink it himself!  
Precisely for this reason many topics related to sensory vices and virtues of coffee, as they originate and by which compounds are given, will be discussed during the modules of the Professional Master of Coffee Science and Sensory Analysis which will be held on next 22-24 September.

The markers of non-quality

by Roberto Zironi

He is professor of Food Industries at the University of Udine and president of the Department of Food Science in the same University. In addition, he is the chair of the scientific committee of the International Institute of Coffee Tasters and vice-president of the International Academy of Sensory Analysis.

Coffee is a drink that expresses most of its sensory characteristics in its smell and its aroma. The aroma is the sensory characteristic resulting from a combination of smells contributed by the chemical substances and by their intrinsic synergies and is the result of high-quality raw materials and of technological steps for the processing of the green matrix into roasted coffee which are thoroughly carried out. It is important to point out that the aromatic precursors are already present in the green bean which, exposed to roasting, develops new substances that contribute to the complexity with more than 800 volatile components found in a cup of coffee.
With regard to coffee, quality is based on two main aspects: the hygienic-sanitary quality, defined by regulations in force, and the sensory quality, defined by the aromatic and sensory profile.
Let us start with the hygienic-sanitary quality. For both the Arabica and Canephora (Robusta) varieties there are regulatory restrictions re the quantity of Ochratoxin A (OTA), secondary metabolite of moulds, mainly belonging to the Aspergillus type, present in both the green and the roasted coffee. Such restrictions are the result of proven negative effects on the consumer’s health. It is interesting to point out how the presence of OTA often goes hand in hand with a low sensory quality given that the attacks of moulds also bring about the formation of several secondary metabolites capable of influencing both the aroma and the taste of the finished product.
The contamination by moulds, coming from the raw material as well as from inadequate conditions during harvesting, processing, storage and transportation is among the factors which have the greatest impact on the sensory quality of a coffee. Components produced by moulds such as the 2-methylisoborneol, the geosmin and the 2,4,6-tricloanisole (TCA), for example, are responsible for major off-flavours: they create sensations of mouldy, earthy phenic, and rio flavour. It goes without saying that the absence of the said flaw-producing elements can be deemed as the first step towards impressive productions. Therefore, the above-mentioned elements can be seen as markers of non-quality to be determined, alongside the traditional parameters, during the qualitative assessment of a batch of green coffee.

In collaboration with: E.Cossio, F.Battistutta