Espresso Italiano Roasting: roasting and blending from the tasters’ point of view

Espresso Italiano Roasting, the new publication from the International Institute of Coffee Tasters, has just been published. It is completely focused on the Italian way of roasting and blending.

Italian espresso stands out as a concrete expression of the elegance typical of “Made in Italy”, products covering the key role of testimonial of our agro-food culture. And this is why science can only resort to all the modern available means to photograph this art, hoping to replicate and innovate it.

And the aim of Espresso Italiano Roasting is all about this, in fact it focuses on collecting and arranging the output of coffee research using appropriate technical terms to promote its diffusion, giving special attention to the current available means in the field of coffee roasting. As a matter of fact, each single chapter and paragraph is soaked in sensory analysis, which is the main tool used at present for selecting green coffee, setting the roasting process and realizing the blends. The countless correlations involving chemistry, technology and sensory results will easily guide the readers, giving them the tools to understand phenomena they have certainly already observed in the past without the necessary competence.

Espresso Italiano Roasting is in fact based on the experience that the author has achieved with the courses held by the International Institute of Coffee Tasters, the thousands of consumer and laboratory tests carried out by the Taster Study Centre and the tens of samples that have undergone sophisticated chemical analysis.

Espresso Italiano Roasting is only available in electronic format (high resolution PDF) and can be ordered on the website of the International Institute of Coffee Tasters. The index and the first chapter are freely downloadable from the same website.

The markers of 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.

The definition of specific markers which describe a coffee all throughout the production process makes it possible to monitor and optimize both its hygienic-sanitary and sensorial quality so that levels of acceptability can be set and anomalies in the composition of the final aroma can be spotted.

Among the various components which contribute to the creation of the aromatic profile of a coffee it is not easy to establish which of them can be defined as markers of quality in that it is necessary to mediate between the characteristics seen as related to the specific coffee and the place of origin and the market needs.

In order to identify the markers of quality for coffee it is necessary to examine the components which determine the positive aromatic characteristics typical of a specific coffee along with the components generated during the roasting process. The point is that while the flaws, as explained in the previous issue of Coffee Taster, come from a few chemical species, the positive elements are the result of the interaction of tens or hundreds of different molecules. Currently, the specialists are trying to identify the individual markers of quality or the simple connections between the elements transformed during the roasting process.

The chemical compounds that produce such distinguishing features are present in the raw material and they undergo major transformations during the roasting process which not only occasion significant transformation of the individual original compounds, but also combines them creating synergies and antagonisms which contribute to determining the final aroma of the beverage.

It is important to note what follows:

  • the body is given by fats, macromolecules and colloids;
  • the perceived acidity is given by the aliphatic volatile and non volatile acids, chlorogenic acids, phenol acids and inorganic acids;
  • the bitterness comes from compounds such as caffeine, trigonelline and chlorogenic as well as chinic acids;
  • the sweetness comes from the sugar compounds still present after the roasting process;
  • the fruity and flowery notes typical of coffees from south America are given by aldehydes, ketones and alyphates.

Moreover, there are several other sets of compounds which contribute to the overall aroma, for instance the furnas – which give the caramel note, pyrazines – toasted note, tiazoli, pyrroles, phenols and thiophenes.

The ratios between such compounds have an impact on quality. For example, the ratio between 4-vinilguaiacol and 4-etilguaiacol, elements which – taken on their own – are characterised by markedly different aromatic notes, is responsible for distinguishing traits, in terms of aroma, of the Arabica and Robusta.

In collaboration with: E.Cossio, F.Battistutta