Poste Italiane SpA - Spedizione in Abbonamento Postale - D.L. 353/2003 (com. L. 27/02/2004 n. 46) art. 1, comma 1 DCB Brescia
dallâ€™analisi sensoriale al piacere
Sensory control of coffee in Italy How far do sensory checks influence coffee choice, production and company choices? When, where and in what way will it be applied and utilised? Can we speak of veritable sensory analysis? We asked the Italian coffee roasters
A good coffee is incredibly satisfying for those sipping in a cafe, those waking up to its enshrouding aroma, those savouring it during a brief break, and those enjoying it after a good meal. A bad coffee is incredibly disappointing, leaving the client unsatisfied: there is nothing worse than to finish an excellent dinner with a terrible coffee, or sip a badly made coffee with a delicious cream pastry. In order to guarantee good coffee, coffee roasting companies select green coffee, develop blending and roasting recipes, and verify that the final result is the desired outcome. And how can they do all of this? On the one hand, it is through instrumental analysis which detects the physical and chemical properties of the beans before and after toasting. On the other hand, it is through continual sensory checks: nothing betters the human sensory system and its capacity to learn.
The Long Road of the Coffee Bean Every cup of coffee that we taste is the result of the actions of numerous actors in a long coffee-production chain. At each ring along the chain, a selection happens and a choice is made based on economic and marketing (and sanitary) assumptions, but also on tradition, experience and taste (local or global). One produces, buys and sells that which one believes can be successful for a specific type of client. The only possible way to be certain that the coffee produced and purchased is of the desired quality for specific objectives is to check its sensory properties. The end-client is the first to decide what to buy, based on the sensory gratification obtained from a specific product. As well as pleasantness, producers also assess the objective characteristics of the result of their work, and this has always been done through tasting, as
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Instrumental Analysis of Coffee The instrumental analysis carried out by the coffee roasting plants use a sieve to measure the size of the beans; a colorimeter to assess the degree of roasting; other useful instruments to determine the degree of humidity of coffee before and after roasting; oxygen analysers to detect the residual percentage of gas in conserved products within a modified atmosphere; electrical laboratory roasters to roast a raw sample in order to compare it to industrial roasting; and finally, analytical determinations to research nutritional factors (carbohydrates, proteins, fats, fibre and minerals) and contaminants with their relative microbiological analyses.
we shall see, using refined and exhaustive methods. In coffee-producing countries, a first sensory check is already carried out on batches and harvests. The most commonly used methodology in this case is the cupping method, i.e. the tasting of samples of lightly toasted processed green coffee and then their assessment when infused (the socalled Brazilian method). From here, coffee can be bought directly from large companies or sold to green coffee retailers, who choose the batches and then resell them in their own counties (or abroad, depending on their size). Finally, green coffee reaches the coffee roasting plant, which chooses the quality and samples that are most suitable for its roasting and blending needs, and continues to assess the sensory profile of coffee during the entire transformation process up to the verification of the quality of the final product. Barista and consumers will give the final verdict.
Coffee Roaster Say Yes We therefore asked 24 coffee roasting plants to indicate the sensorial check methods used within their companies. The work of the coffee roasting plant in fact starts with the choice of the green coffee which will be roasted and eventually blended. Depending on the size of the company, its needs, its stock and the contacts it has established with producing countries rather than with raw Italian producers, the 6
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entrance of primary materials may change. Companies with a commercial role do not carry out checks on the raw product insofar as their associated companies or the importer takes care of this phase. In order to reduce the long process of assessment and purchase, large companies decided to qualify laboratories directly within their countries of origin, thus obtaining prescreening. At times, however, the product is even sold before the harvesting to advance takings. Many coffee roasting plants, however, perform a sensory analysis on the raw material they wish to buy. These checks are performed by a single judge or by a group of judges which, in some cases, is composed of 8 individuals, but more often involves only three trusted people (the manager of the company and quality experts), only when raw batches of particular characteristics are added does the judgement get extended to a greater number of people. During this phase, the coffee roasters hope to evaluate the arriving batches, choosing those with traits which are best adapted to the blends and roasts that characterise the company and verifying the sometimes subtle differences between different samples. These analyses are performed by means of sensory assessments of the raw and roasted beans and of the ground coffee after infusion, in an espresso machine or moka, uniformly roasting the arriving batches. Roasted coffee is instead assessed by a larger number of judges, sometimes also includ-
ing trusted clients who have often been trained by means of coffee tasting and sensory analysis courses. The checks are carried out by taking batches of samples during the different roasting phases, mainly through blind tasting using the espresso method, both with and without sugar, but also using the moka (should the blend be destined for this use) or infusion method (Brazilian method). Finally, roasted coffee can be checked over time in order to assess its quality after oxygen exposure through the use of triangular tests. These help to identify slight variations which may be due to variation in the batches that make up the blend or to a variation during the conservation phase.
The Coffee Roasters’ Sheets The methodologies of sensory evaluation used by coffee roasters are very diverse and they rarely use internationally standardised techniques. Everything is left to the discretion of the coffee roasters and their collaborators. Normally, in the development of the assessment sheets influences can be observed from one of the international methods, SCAA and IIAC, which are however revisited, personalised and adjusted to individuals’ needs (an undeniable fact as long as a scientific basis and proven methods are maintained). To understand what happens during a tasting, one may simply observe the sheets used by the different coffee roasting plants. The same sheet is almost always used for raw
and roasted coffee and for any specimen, where information is usually indicated in specific boxes. Then starts the gathering the data of the sample and of the judge, including the number of the batch, the type of coffee and blend examined, the supplier, the harvest season, the type of roasting used and the name of the assessor. Naturally, the doubt surrounding the fact that samples are not blind tested thus arises (unless this part of the sheet is only completed after the tasting). The risks in this case would be numerous: if I know the name, processing characteristics and raw or blend supplier, I could in fact create expectations for myself or generalise (the coffee offered to me by that supplier is always good, therefore this one will also be good), or even constrain judges’ freedom, making them feel as if their performance is being observed. During sensory analysis, data relative to the sample must be completely absent from the sheet in order to release the judgement from external influences as far as possible. Only later should the leader of the panel read the information gathered about the sample characteristics. Finally, the section dedicated to true sensory assessment is reached. This is usually divided into phases. A first unit is dedicated to the description of the raw bean, from which the appearance, roasted colour, colour homogeneity, sieve, odour, humidity and shrinkage on purchase are assessed. The section dedicated to the in-cup tasting of green or blended coffee follows, starting with a visual phase in which the appearance of the coffee and, in particular, of its foam (colour, texture, consistency, persistence), is observed, normally in the espresso form. Subsequently, olfactory sensations are assessed in their entirety: aroma, intensity of aroma, depth, persistence, delicacy, harmony, elegance, balance. Many sheets finish with a single taste section in which retro-olfactory sensations are often included. Following the logic of sensory analysis and of some coffee roasters who, instead, distinguish these two moments, in the phase of taste assessment descriptors are used such as intensity, depth,
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body, bitter, acidic, astringent, sweet, delicacy, harmony, elegance, balance and taste persistence. For the retro-olfactory phase, known as “retro-taste” in coffee roasting plants, we observe: retro-nasal intensity, retro-nasal persistence, retro-taste, delicacy, richness, positive aromas, defects (which at times are positioned in freestanding boxes). In these sheets the descriptors, i.e. the terms indicating the traits to be measured by sensory analysis, are often used without any distinction between objective ones (measured through collimation) and hedonic ones (in which the assessment by each individual remains entirely subjective), as for example, the assessment of acidic and astringent traits together in balance, or the assessment of only the richness and elegance of the “retro-taste”, or giving a generic measurement of “retro-taste” (perhaps on a semantic scale that goes from unsatisfactory to excellent). In some sheets, the meaning of the descriptors is provided, effectively reminding the judges of what they must look for and assess. Ample space is often left for free descriptors (i.e. spaces in each section in which the judges can enter traits surveyed and assessed by themselves), in part because it is useful information, and in part because many perceptions are not given space among the few and vague indicated descriptors. Even the scales used are very varied: linear numeric from 1-10 or 1-5, linear numeric and semantic scales (poor, unsatisfactory, weak, satisfactory, decent, good, excellent), three-point semantic scales (weak, average, good), or those that ask for an evaluation directly on an empty radar graph with a scale from 0-9. Much variation may be simplified by using good descriptors with a simple numbered scale from 0-9, assisted by free descriptors. At the end of the sheets, a final judgement is required on the sample, ruling upon whether it will suffice or not, through the notes and overall assessment: i.e. “explain your thoughts in a few words”. The sensory assessment work conducted in coffee roasting plants is thus complex and in continual development, but does not preclude the possibility of standardising and 8
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The Survey Method The information here described originated from a research conducted on a sample of 571 companies to which a series of 12 questions were sent via e-mail, as well a request for them to send the sheets used to conduct the sensory assessment of raw material, roasted material and final product. As is common to this type of survey, replies were only obtained from a percentage of these companies who provided accurate replies in compensation.
refining the assessment sheets used, and of rendering them uniform and mutually comparable. The survey in fact allowed for the revelation of the coffee roasters’ need to use sheets that are based on scientific methodologies, such that many companies decided to adopt in part, or aspire to the coffee sensory analysis sheets used by the International Institute of Coffee Tasters. This allows for more information to be obtained, rendering the assessment parameters more intelligible both between different companies and within the same company: a clear and shared vocabulary and metre which, through sensory certifications, can finally become understandable to consumers.
Claudia Ferretti and Valentina Maccini firstname.lastname@example.org
Published on Nov 9, 2011
How far do sensory checks influence coffee choice, production and company choices? When, where and in what way will it be applied and utilis...