Smells like Coffee Spirit: Sensorik
Seeing, hearing, feeling, smelling and tasting – that is sensory perception. And this is also what determines whether we like something or not. For example, standard red ketchup is a hit, while purple and green ketchup was a flop. Sensory perception, or sensory perception, is a broad field. Everyone perceives things differently, yet there are scientific principles that cannot be disputed. The term ‘sensory perception’ is usually used in relation to food to refer to ‘taste’, which is wrong in several ways. Sensory perception encompasses all sensory perceptions, i.e. seeing, hearing, feeling, smelling and tasting.
All these perceptions are taken into account when evaluating a food product and, together with the socio-cultural influences of the test person, determine whether a food product is considered attractive – i.e. appetising – or unattractive – i.e. unappetising. Even a change in a single parameter can significantly influence perception (e.g. green instead of red tomato sauce). This experiment also works very well when using Blue Curaçao instead of colourless Triple Sec (orange liqueur) in the preparation of Crêpes Suzette – bon appétit! A food that does not fit the ‘prey pattern’ visually will no longer be subjected to an olfactory (smell) or gustatory (taste) test. The same applies to smell perception, which can also lead to the rejection of food if its appearance is completely as expected. If the food has an unexpected or ‘negative’ smell (scientifically referred to as off-flavour), the product will be rejected.An example of this would be a cheese smell, which would be considered appropriate and pleasant for cheese, but strange and unpleasant for coffee. It is important to note that there are no positive and negative smells (this is a common misconception of on-flavour and off-flavour), but rather, as described above, it is a matter of whether or not the aroma or aromas underline the expectation. Sommeliers and oenologists are already familiar with the sequence of evaluating a wine: ‘colour, odour, sapour’ (colour, smell, taste). The sound of a food, such as the crunching sound of bread crust, the pouring sound of beer or even associated sounds (the popping of a champagne cork, the hissing sound when opening a bottle cap) are also included in the evaluation, expectations and conditioning. It is understandable for evolutionary and logical reasons that this sequence corresponds to the distance perception of the individual characteristics of a food. Humans are able to see further than they can hear or smell. In turn, hearing is possible from a greater distance than the taste and haptic perception felt by the tongue and mouth.
The taste evaluation takes place in the mouth and nasal cavity after visual and acoustic evaluation. The term ‘taste’ presents the first hurdle here, as it is used both to describe gustatory perception (according to classical teaching: sweet, sour, salty, bitter and umami, Japanese for ‘savoury’) and as a general term for gustatory, olfactory and haptic perception. In English, there are two separate terms, with overall perception being referred to as ‘flavour’ and gustatory perception as ‘taste’. It seems curious that individual languages have gaps in their vocabulary – which are then usually covered by double meanings – another very prominent example in the German language is ‘Himmel’, which can mean both “sky” and ‘heaven’. It is therefore not an unnecessary Anglicism to speak of ‘taste’ and ‘flavour’ in the field of sensory analysis, but merely serves to simplify and clarify.
Flavourings: These are produced through various processes. In the case of coffee, for example, it is dry heating, i.e. roasting. Smells (aromas) are perceived orthonasally (through the front nasal cavity) and retronasally (rising from the back of the oral cavity). In addition to taste and smell, mouthfeel is also evaluated. Flavourings are formed in two ways: enzymatically and non-enzymatically. The non-enzymatic reactions (Maillard processes) take place during processing and storage. In plant-based products, most flavour formation can be attributed to enzymatic reactions, whereas animal products are initially low in flavour and only develop their typical flavours through processing and storage.
The most important processes here are the Maillard reaction, Strecker degradation and lipid peroxidation. The Maillard reaction is the main process involved in flavour formation during coffee roasting (dry heating). The starting materials are reducing sugars, amino acids, peptides and proteins. The haptic sensation – i.e. the mouthfeel – is composed of the perceptions of the afferent nerve fibres. In addition to temperature perception (hot and cold), this also includes pain perception (which also includes spiciness) and the perception of consistency and viscosity. Haptics (in this case, oral tactile perception) is often referred to as ‘body’. Haptics also has retronasal effects. These are caused by isothiocyanates (found in mustard and horseradish, for example), which rise retronasally and cause a burning sensation in the nose (through the passage connecting the nasal cavity and the eyes) and also in the eyes. In English, there are good references to the relationship between oral haptic sensory perceptions. For example, ‘hot’ refers to both the thermal properties of food and the increased perception of spiciness.
Viscosity can be easily described by the different mouthfeel of water and oil. Oil, which is significantly thicker and more viscous, differs markedly from water in terms of tactile perception. In the coffee sector, espresso in particular – when correctly prepared – has an almost creamy, buttery mouthfeel that can be compared to liquid cream.
Depending on the temperature, the three sensory components of flavour – taste, texture (body) and aroma – are perceived to varying degrees. At body temperature, the three perceptions are balanced, while the aroma decreases significantly at colder temperatures and the taste recedes at higher temperatures. Haptics, on the other hand, benefit from high and cold temperatures (since temperature directly influences haptic perception).
This is easy to understand when it comes to wine, which releases more aromas at higher temperatures (e.g. red wine) and tends to be more ‘closed’ at lower temperatures (e.g. white wine). In professional coffee tasting (cupping), coffee is also tasted at different temperatures – but never too high. The best overall perception of the flavour is found in a temperature range around body temperature. Good and excellent coffees still taste good after cooling down and still present a balanced profile. Perceptions change and influence each other depending on the cultural area, personal experiences and preferences derived from them – but also depending on the season, time of day, physical condition and the food and drinks consumed beforehand. It is therefore understandable that Arabica and Canephora coffees enjoy different levels of popularity in different countries. In warmer countries – with higher tolerance thresholds for bitterness – Canephora coffees and dark roasts are popular. This results in light roasts, which are usually made from pure Arabica coffees. Regardless of regional and cultural influences, everyone can still fully appreciate and identify rankings and intensities of taste or smell. Similarly, different flavour profiles can be easily distinguished in a direct comparison. This can be easily demonstrated in triangular tests, in which three cups (two of them with the same contents) are placed in front of the test person in a triangular arrangement and the test person then pushes the cup with a different taste out of the triangle.
Verbalising sensory perception, especially that of a flavour profile, requires some practice and, above all, a regular and orderly process. It is important to first orientate oneself in larger groups, i.e. to divide the aromas into groups and then find individual descriptions within the group. Flavours can be divided into different main groups (green plants and herbs, fruits, flowers, roasted flavours, wood tones, etc.). Within a group (e.g. ‘fruits’), further differentiation can then be made by describing the fruit flavours in more detail (e.g. lemon, orange, cassis, peach, etc.).
It is enjoyable to consciously taste coffee and savour it with all your senses. The easiest way to do this is to consciously focus on each individual perception one after the other and allow them to sink in. And if it doesn't work right away, remember that practice makes perfect... We also offer sensory workshops: https://coffee-consulate.com/CoffeeSensorist/Coff-Sens
So-called aroma boxes are available for training the senses. These have long been proven effective for wine. The bottles contain various aroma samples, which can also be found in different dosages in coffee. This box, ‘Lenez du café révélation’, contains 36 bottles. It comes with a book that explains the different aroma families and the characteristics of the scents. It also explains the degree of presence of each scent in coffees of different origins. Furthermore, the role of the sense of smell, the method of tasting and the roaster's working methods are explained. An exciting, if not entirely inexpensive, game for the senses.
All these perceptions are taken into account when evaluating a food product and, together with the socio-cultural influences of the test person, determine whether a food product is considered attractive – i.e. appetising – or unattractive – i.e. unappetising. Even a change in a single parameter can significantly influence perception (e.g. green instead of red tomato sauce). This experiment also works very well when using Blue Curaçao instead of colourless Triple Sec (orange liqueur) in the preparation of Crêpes Suzette – bon appétit! A food that does not fit the ‘prey pattern’ visually will no longer be subjected to an olfactory (smell) or gustatory (taste) test. The same applies to smell perception, which can also lead to the rejection of food if its appearance is completely as expected. If the food has an unexpected or ‘negative’ smell (scientifically referred to as off-flavour), the product will be rejected.An example of this would be a cheese smell, which would be considered appropriate and pleasant for cheese, but strange and unpleasant for coffee. It is important to note that there are no positive and negative smells (this is a common misconception of on-flavour and off-flavour), but rather, as described above, it is a matter of whether or not the aroma or aromas underline the expectation. Sommeliers and oenologists are already familiar with the sequence of evaluating a wine: ‘colour, odour, sapour’ (colour, smell, taste). The sound of a food, such as the crunching sound of bread crust, the pouring sound of beer or even associated sounds (the popping of a champagne cork, the hissing sound when opening a bottle cap) are also included in the evaluation, expectations and conditioning. It is understandable for evolutionary and logical reasons that this sequence corresponds to the distance perception of the individual characteristics of a food. Humans are able to see further than they can hear or smell. In turn, hearing is possible from a greater distance than the taste and haptic perception felt by the tongue and mouth.
The taste evaluation takes place in the mouth and nasal cavity after visual and acoustic evaluation. The term ‘taste’ presents the first hurdle here, as it is used both to describe gustatory perception (according to classical teaching: sweet, sour, salty, bitter and umami, Japanese for ‘savoury’) and as a general term for gustatory, olfactory and haptic perception. In English, there are two separate terms, with overall perception being referred to as ‘flavour’ and gustatory perception as ‘taste’. It seems curious that individual languages have gaps in their vocabulary – which are then usually covered by double meanings – another very prominent example in the German language is ‘Himmel’, which can mean both “sky” and ‘heaven’. It is therefore not an unnecessary Anglicism to speak of ‘taste’ and ‘flavour’ in the field of sensory analysis, but merely serves to simplify and clarify.
Flavourings: These are produced through various processes. In the case of coffee, for example, it is dry heating, i.e. roasting. Smells (aromas) are perceived orthonasally (through the front nasal cavity) and retronasally (rising from the back of the oral cavity). In addition to taste and smell, mouthfeel is also evaluated. Flavourings are formed in two ways: enzymatically and non-enzymatically. The non-enzymatic reactions (Maillard processes) take place during processing and storage. In plant-based products, most flavour formation can be attributed to enzymatic reactions, whereas animal products are initially low in flavour and only develop their typical flavours through processing and storage.
The most important processes here are the Maillard reaction, Strecker degradation and lipid peroxidation. The Maillard reaction is the main process involved in flavour formation during coffee roasting (dry heating). The starting materials are reducing sugars, amino acids, peptides and proteins. The haptic sensation – i.e. the mouthfeel – is composed of the perceptions of the afferent nerve fibres. In addition to temperature perception (hot and cold), this also includes pain perception (which also includes spiciness) and the perception of consistency and viscosity. Haptics (in this case, oral tactile perception) is often referred to as ‘body’. Haptics also has retronasal effects. These are caused by isothiocyanates (found in mustard and horseradish, for example), which rise retronasally and cause a burning sensation in the nose (through the passage connecting the nasal cavity and the eyes) and also in the eyes. In English, there are good references to the relationship between oral haptic sensory perceptions. For example, ‘hot’ refers to both the thermal properties of food and the increased perception of spiciness.
Viscosity can be easily described by the different mouthfeel of water and oil. Oil, which is significantly thicker and more viscous, differs markedly from water in terms of tactile perception. In the coffee sector, espresso in particular – when correctly prepared – has an almost creamy, buttery mouthfeel that can be compared to liquid cream.
Depending on the temperature, the three sensory components of flavour – taste, texture (body) and aroma – are perceived to varying degrees. At body temperature, the three perceptions are balanced, while the aroma decreases significantly at colder temperatures and the taste recedes at higher temperatures. Haptics, on the other hand, benefit from high and cold temperatures (since temperature directly influences haptic perception).
This is easy to understand when it comes to wine, which releases more aromas at higher temperatures (e.g. red wine) and tends to be more ‘closed’ at lower temperatures (e.g. white wine). In professional coffee tasting (cupping), coffee is also tasted at different temperatures – but never too high. The best overall perception of the flavour is found in a temperature range around body temperature. Good and excellent coffees still taste good after cooling down and still present a balanced profile. Perceptions change and influence each other depending on the cultural area, personal experiences and preferences derived from them – but also depending on the season, time of day, physical condition and the food and drinks consumed beforehand. It is therefore understandable that Arabica and Canephora coffees enjoy different levels of popularity in different countries. In warmer countries – with higher tolerance thresholds for bitterness – Canephora coffees and dark roasts are popular. This results in light roasts, which are usually made from pure Arabica coffees. Regardless of regional and cultural influences, everyone can still fully appreciate and identify rankings and intensities of taste or smell. Similarly, different flavour profiles can be easily distinguished in a direct comparison. This can be easily demonstrated in triangular tests, in which three cups (two of them with the same contents) are placed in front of the test person in a triangular arrangement and the test person then pushes the cup with a different taste out of the triangle.
Verbalising sensory perception, especially that of a flavour profile, requires some practice and, above all, a regular and orderly process. It is important to first orientate oneself in larger groups, i.e. to divide the aromas into groups and then find individual descriptions within the group. Flavours can be divided into different main groups (green plants and herbs, fruits, flowers, roasted flavours, wood tones, etc.). Within a group (e.g. ‘fruits’), further differentiation can then be made by describing the fruit flavours in more detail (e.g. lemon, orange, cassis, peach, etc.).
It is enjoyable to consciously taste coffee and savour it with all your senses. The easiest way to do this is to consciously focus on each individual perception one after the other and allow them to sink in. And if it doesn't work right away, remember that practice makes perfect... We also offer sensory workshops: https://coffee-consulate.com/CoffeeSensorist/Coff-Sens
So-called aroma boxes are available for training the senses. These have long been proven effective for wine. The bottles contain various aroma samples, which can also be found in different dosages in coffee. This box, ‘Lenez du café révélation’, contains 36 bottles. It comes with a book that explains the different aroma families and the characteristics of the scents. It also explains the degree of presence of each scent in coffees of different origins. Furthermore, the role of the sense of smell, the method of tasting and the roaster's working methods are explained. An exciting, if not entirely inexpensive, game for the senses.