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International Institute of Coffee TastersESPRESSO ITALIANO ROASTING

Author: Luigi Odello

Technical revision: Giuseppe Versini

Collaborators: Michela Beltrami, Gian Paolo Braceschi, Claudia Ferretti, Carlo Odello, Manuela Violoni

Translation: Mydioma

Layout: Agency ArtisticaMente

Picture acknowledgements: Carlo Odello

Thanks: to Giuseppe Versini for revising the chemical part, to Fernanda Rosan Fortunato Seixas for her help with research, to Novella Bagna for the statistical data processing

L’Assaggio no. 15 – October 2009 – Authorization Court of Brescia no. 36 of 10th October 1995 – Editor-in-chief: Luigi Odello – Publisher: Centro Studi Assaggiatori Soc. Coop., Galleria Veneto 9, 25128 Brescia (Italy) – © Luigi Odello

www.italiantasters.com – info@italiantasters.comwww.coffeetasters.org – info@coffeetasters.org

Price: 25,00 € (VAT included)

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Foreword 9

What goes into the roasting machine and what comes out 10

What we put in the roasting machine 11What happens in the roasting machine 11What leaves the roasting machine 12Art plays its role between entrance and exit 12

Coffee macroconstituents and their behaviour during the roasting process 14

carbohydrates 14Technological correlations and thermal behaviour 15Carbohydrates according to chemistry 15Sensory effects 16Main carbohydrates in coffee 16

Lipids 17Technological correlations and thermobehaviour 17Lipids according to chemistry 18Which fatty acids does coffee contain? 19Unsaponifi ables 19Sensory effects 19

Nitrogen compounds 20Polyamines 20Amino acids 20Proteins 20Caffeine 20Trigonelline 21Technological correlations and thermobehaviour 21Sensory effects 22Nitrogen compounds according to chemistry 23

Acids 23Aliphatic acids 23Chlorogenic acids 24Inorganic acids 24Technological correlations and thermobehaviour 24

Aliphatic acids 24Chlorogenic acids 25

Sensory effects 25Acids according to chemistry 26

Minerals 27

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Selecting green coffee 28Most common faults 28

Black bean (preto) 28Unripe bean (quaker) 28Fermented bean (ardido) 29Stinker bean 29Mouldy bean 29Earthy bean 29Waxy bean 29Peasy bean 30Whitish bean (biancone) 30Corked (rioy) bean 30Worm-eaten bean 30Dark brown bean 30Misshapen bean 30Dark green bean 31Nipped bean 31

The art and science of roasting 32

Roasting style does not depend on origin 32Many blend components from the same raw material 33Nothing can only generate nothing 34Right fi re at the right time 34What can be produced may be destroyed 35Science can only support art 35

Roasting and aroma development 37Acids 37Alcohols 37Aldehydes 37Amines 38Ketones 38Esters 38Phenols 38Furans 39Hydrocarbons 39Lactones 39Mercaptans 39Oxazoles 40Pyrazines 40Pyridines 40

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Pyrroles 40Sulphides 40Thiazoles 41Thiophenes 41Thiols 41

The roasting process 42

Process stages 42Stage one: 120-130°C 42Stage two: 130-140°C 42Stage three: 140-160°C 42Stage four: 160-190°C 42Stage fi ve: 190-220°C 43

Roasting curves 43Roasting styles 45

First quadrant: short time/high temperature 45Second quadrant: long time/high temperature 45Third quadrant: long time/ low temperature 46Fourth quadrant: short time/low temperature 46

Cooling 46Forced air cooling 46Nebulised water cooling 46

Green coffee selection and roasting: chemical and sensory codes 48

The 5 categories of molecules 49Negative 49Positive 49Mutant 49Schizoid 50Killer 50

Descriptors and correlations 51Colour intensity 51

Defi nition 51Production process correlations 51Positively correlated molecules 51

Texture 51Defi nition 51Production process correlations 51Positively correlated molecules 51Negatively correlated molecules 51

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Appeal 51Defi nition 51Production process correlations 52Positively correlated molecules 52Negatively correlated molecules 52

Body 52Defi nition 52Production process correlations 52Positively correlated molecules 52Negatively correlated molecules 52

Acid 52Defi nition 52Production process correlations 53Positively correlated molecules 53Negatively correlated molecules 53

Bitter 53Defi nition 53Production process correlations 53Positively correlated molecules 53Negatively correlated molecules 53

Astringency 53Defi nition 53Production process correlations 53Positively correlated molecules 53Negatively correlated molecules 54

Tasting balance 54Defi nition 54Production process correlations 54Positively correlated molecules 54Negatively correlated molecules 54

Tactile balance 54Defi nition 54Production process correlations 54Positively correlated molecules 54Negatively correlated molecules 54

Olfactive intensity 54Defi nition 54Production process correlations 54Positively correlated molecules 55

Flowers and fresh fruit 55Defi nition 55Production process correlations 55Positively correlated molecules 55Negatively correlated molecules 55

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Vegetable 55Defi nition 55Production process correlations 55Positively correlated molecules 55

Nuts and dried fruit 56Defi nition 56Production process correlations 56Positively correlated molecules 56

Roasted 56Defi nition 56Production process correlations 56Positively correlated molecules 57

Spicy 57Defi nition 57Production process correlations 57Positively correlated molecules 57

Empyreumatic 57Defi nition 57Production process correlations 57Positively correlated molecules 57

Different biochemicals 58Defi nition 58Production process correlations 58Positively correlated molecules 58

Global positive odour 58Defi nition 58Production process correlations 58

Global negative odour 58Defi nition 58Production process correlations 58

Aroma persistence 59Defi nition 59Production process correlations 59Positively correlated molecules 59

Delicacy 59Defi nition 59Production process correlations 59

Richness 59Defi nition 59Production process correlations 59

Hedonic level 59Defi nition 59Production process correlations 59

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The art of blending 60Assessing the blend 61

Perfection 61Depth 61Power 61

Axioms and postulates in blend creation 61Happy unions are created by affi nity and complementarity, never by contrast 62No additions in blend creation, only multiplications. And they must be of the algebraic kind 62The hedonic output of a blend can only be sensorially assessed, yet chemical analysis may be of great help 63Small quantities of a coffee variety containing killer molecules can depress blend overall depth 63

How many components make a high quality blend? 64

Internationa Institute of Coffee Tasters 65

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ForewordIn the great majority of cases roasters do not grow coffee, the sector lacks in experimentation and, in addition, there are no technical operators able to set up a specifi c network which could also act as connection with the research centres promot-ing innovation: these are the three elements that make the cof-fee sector different from any other in the food industry.However there is something special that all the rest of the world envies about Italian espresso. It is not just the prepara-tion method, which could be copied, but the ability of the roasters in selecting raw materials and in processing them with techniques derived from experience and qualifi ed by outstanding sensitivity combined with equal good taste.Hence, 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 dif-fusion, giving special attention to the current available means in the fi eld 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, set-ting the roasting process and realizing the blends. The count-less 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. The publication 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 car-ried out by the Taster Study Centre and the tens of samples that have undergone sophisticated chemical analysis.Only a solid record, output of years of effective experimental program, can provide suffi cient data for approaching such a complex subject with a totally new attitude.

Roberto ZironiFull Professor at Udine University

Head of the Department of Food SciencesChairman of Absis Consulting

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What goes into the roasting machine and what comes out

Just two main factors are sufficient to describe a mundane matter, and they are what is put in a roasting machine and what leaves it. Yet another issue, this time not banal, is all about what we decide to put into the roaster and how we roast it to get the coffee we want. Among possible options here is an example: Italian espresso, which is a product ground at moment of use, pressed and extracted in a 9 bar pressure machine at a temperature of approxi-mately 90°C, in 25 seconds giving a 25 milligram cup of syrup enriched by hazelnut colour cream with reddish reflexions, velvety and silky body, aroma covering the whole olfactive range, from flowers and fresh fruit scents to spicy ones, experiencing nutty and roasted notes. The whole, of course, in absence, or with extremely slight hints, of vegetable smells, and absolutely free from alien biochemical odours.So the fi rst stage is all about choosing the right green cof-fee: very complex, diffi cult, always risky. It is your nose that guides you, in the real sense of the word, as it is the sense of smell once again that experienced roasters rely on to make their decisions. Laboratory roasters in different sizes (from 100 grams to a kilo) are fi lled with coffee and heated to reach the desired degree of baking. This is the fi rst, sometimes le-thal, stage: no matter how much effort is put in the test as a reduced scale process never compares to the industrial one. As you will learn, the thermal fl ywheel that is produced by the cof fee aggregate, especially when it passes from endo-thermic stage to exothermic, is correlated to the size of the aggregate itself, yet it is no linear correlation.And this is not the only trap on the path roasters must follow. An even more threatening one involves a series of molecules, which can not be perceived, but are potentially devastating for the global results if they happen to be included in a blend. Killer molecules stand out as the worst danger: they do not show off but can block the perception of fi ne and costly blend components. This is why it is impossible to rely on small scale roasting to overcome such obstacle. It will just not work, as nobody will ever know which coffee typologies have been annihilated and which have not been fully utilized. Luckily

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CONSTITUENTS ARABICA ROBUSTA

Carbohydrates 60 60

Lipids 16 10

Nitrogen compounds 13 14

Acids 7 11

Minerals 4 5

analytical techniques are rapidly improving: nowadays it is possible to monitor killer molecules while highlighting those carrying positive notes.

WHAT WE PUT IN THE ROASTING MACHINE

Coffee beans are just put in the roaster and nobody seems to care about what they are and what they are made of. Actu-ally they are coffee seeds coated in variable measure by the endocarp (the parchment skin), and totally by the mesocarp (the pulp rich in sugars and acids) and the exocarp (the yel-low or red outer skin). A whole set of intersecting variables infl uence the composition of the beans that will go into the roaster, generating a non defi ned number of variables including genetics (species, variety, etc), farming environ-ment (soil, climate, orientation, insect and parasitic attack), growing techniques, harvesting processes and times, green coffee preparation methods, selection techniques and stor-ing conditions. This must not come as a surprise as coffee beans feature a complex system of thick wall cells that act as a container for some hundreds of chemical compounds. 5 compound classes make up the schematic chemical com-position of the material that goes into the roasting machine (table1), but such a description, despite its accuracy, is only a rough outline: it is just like describing a human being list-ing its essential components expecting to be able to infer its aesthetic features.

Table 1 – Introduction to the chemical composition of raw coffee

WHAT HAPPENS IN THE ROASTING MACHINE

In the roaster the beans are heated and virtually become a chemical reactor for their own constituents. In the fi rst stage (endothermic) heat propagates from their surface to the inte-rior, conveyed by conduction, steam and carbon dioxide. In the second stage (exothermic) the constituents of coffee start producing heat. It is the beginning of a combustion process that could destroy the beans if not interrupted at the right moment.

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WHAT LEAVES THE ROASTING MACHINE

Beans whose physical and chemical features have been to-tally transformed come out of the roaster. The new features include lack of suppleness, average 60% volume increase, humidity reduced by nine tenths, sugar contents fi ve times inferior to previous and, due to weight reduction that can even reach 20%, higher fat and nitrogen compound percent-ages. Yet the true miracle is that these beans have turned into treasure chests crammed with aromas, protected by an atmo-sphere made of carbon dioxide.The explanation is that the basic constituents have formed new chemical compounds. Such compounds have reacted among themselves generating new ones, which have then created a third generation of elements and, in certain cases, a fourth and a fifth. Therefore any slight difference in raw coffee is exaggeratedly amplified and a tiny imperfection can cause a catastrophe in the final sensory scenario.

ART PLAYS ITS ROLE BETWEEN ENTRANCE AND EXIT

Over the last twenty years we have been trying to get the best advice from the master roasters from the homeland of espresso. At the beginning we deemed them reticent, as we did not understand their total reluctance when it came to talk about their skills and how they were performed. It was only later on that we realized that a great blend can not be ana-lyzed in detail as there are no words to explain how it is cre-ated and why a certain process must be followed to obtain it: it is a matter of sensitivity that starts with the roaster, hands joined in prayer position and moving like a Buddhist monk, taking a handful of coffee beans to his nose. In that very mo-ment he might have detected the potential but is not be able to explain it.This is why no school can teach you how to become a mas-ter roaster. The only way to learn is just staying in close contact with one for half of your life, to then pass your skills on to your personal close disciple for the other half. This also tells you why, among the many who feed the roaster with coffee sacks, it is just a few who achieve a dream product.Therefore this book will not solve the problems of those who can not roast, but we hope to give our contribution to who is already suffi ciently skilled. Hence we will not present

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recipes, and are aware we will not succeed in clarifying this unbelievable complex universe, in great parts virgin, in just a few pages.The secrets of roasting and the art of blending Italian espres-so make up a mighty heritage, our attempt is that of provid-ing a key any reader can understand and, hopefully, use to open up a great new passion.

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International Institute of Coffee Tasters

The International Institute of Coffee Tasters (Iiac) is a non-profi t association supported by members’ fees only, and founded with the aim of compiling and spreading scientifi c methods for sensory evaluation of coffee.It has always focused on espresso, the symbol of made in Ita-ly, perfecting a specifi c tasting method. Since its creation Iiac has carried out hundreds of coffee tasting license courses, at-tended by operators and coffee lovers from all over the world. Still in the training sector, in 1999 Iiac created the Espresso Italiano Specialist course for certifying operators working in coffee shops serving Certifi ed Italian Espresso.Further evolution in didactics since 2005 has allowed the re-alization of the Professional Master of Coffee Science and Sensory Analysis, which includes fi ve educational modules. In fi fteen years of activity the association has reached more than 6.000 people that have attended the courses, accom-plishing important missions abroad, involving big consumers like Japan, the United States and Germany as well as produc-ers like Columbia, Brazil and Mexico.During its research activity, supported by a high level sci-entifi c committee, Iiac has perfected the taster cup, which optimizes espresso assessment, while carrying out important studies on the correlations existing between quality markers detected through chemical analysis and the coffee sensory characteristics.

INTERNATIONAL INSTITUTEOF COFFEE TASTERS

Luigi Odello, Carlo Odello

Espresso Italiano Tasting(versions: Italian-English, French-German, Spanish-Portuguese,Russian, Thai, Japanese)

Learn how to single out the quality of thebeans that make a cup of coffee, the mas-tery of the roaster, the efficiency of thegrinder-dosers and machines, the skill of

the barista: this is the goal set by Espresso ItalianoTasting, the first book dedicated to sensory analysis and to theappreciation of the famed Italian beverage.Espresso Italiano Tasting is the summation of what has beenachieved in the coffee sensory evaluation field, over fifteenyears, by the International Institute of Coffee Tasters and by thelarge community of experts who are part of it. Espresso ItalianoTasting is clear and effective and deals with topics such as: howto taste coffee, qualities and possible defects of a cup ready forconsumption, the card and the method to follow for correct sen-sory assessment, coffee geography and production process,the art of blending and roasting, equipment and tips for makingexcellent espresso.Available in Italian and English, Spanish and Portuguese,French and German, Russian, Japanese and Thai.

Bilingual editions: € 18, 00 + shipping costsRussian edition: € 13, 00 + shipping costs

Japanese edition: info@coffeetasters.jpThai edition: info@coffeetasters.org

I libri

Luigi Odello

Espresso Italiano Specialist(versione italiano-inglese)

(Italian-English version)

The golden rules for making Certified ItalianEspresso, the training of baristas to performthis important mission, how to select andmanage blends and equipments to make a

cup of coffee able to guarantee consumers’ full satisfaction: apool of experts will tell you all the secrets of one of made in Italy‘ssymbols that is conquering the world. Espresso Italiano Specialist is the result of the important experimen-tal work that the Italian Espresso National Institute, the InternationalInstitute of Coffee Tasters and the Taster Study Center, carried out incollaboration with university professors and company experts oper-ating in the world of coffee. Espresso Italiano Specialist is a clear pub-lication addressed to all those who are involved with Italian Espressoby profession or passion, to who prepares it and also to wise con-sumers wishing to get maximum satisfaction from this Italian drink.

Bilingual edition (Italian/English): € 18, 00 + shipping costs

The authorsLuigi Odello, professor of sensory analysis at Italian and foreignuniversities and journalist, is a freelance and member of the boardof companies dealing with technological innovation, tasting andsensory analysis. Regarding the coffee sector, he is secretary gen-eral of the Italian Espresso National Institute and of the Internation-al Institute of Coffee Tasters. He is the director of magazine L’As-saggio, writes for national newspapers, has written ten books andis chairman of the Taster Study Center.

Carlo Odello is member of the board of companies dealing withquality product and sensory analysis. He is a journalist and alsocommunication manager for institutions operating in the world ofcoffee. He is member of the board of directors of the InternationalInstitute of Coffee Tasters.