Wine evaluation

sensory and analytical testing

Nevertheless, one cannot do without a "subjective" test with sensory tasting by humans; rather, the two methods complement each other and only when combined do they produce a "fair" assessment. A person can determine the taste "sweet", but never exactly how many grams of sugar are contained in a litre of wine. Analytical testing, however, cannot determine whether a wine "tastes" good. There is the phenomenon of national likes and dislikes. In general, Austrians and Germans prefer acidic, Italians bitter, Americans sweet and French astringent tastes, although such generalisations should be considered with caution. The lighting in a room also influences the taste of a wine: for example, a wine tastes better in red and blue light than in green or white light, as scientists from the Psychological Institute of the Johannes Gutenberg University in Mainz found out. The study showed that the test wine tasted about 1.5 times sweeter under red light than under white or green light. The fruitiness was also rated highest under red light.

professional tasting

Professional tasters can, however, avoid such influencing factors and judge a wine "fairly" and "objectively" by disregarding their personal likes and dislikes. However, this can only be achieved through years of practice and experience. In order to eliminate the influence of external circumstances such as the above-mentioned lighting, professional tastings take place in a sparse, neutral environment. The famous English taster Michael Broadbent (1927-2020) has tasted over 70,000 wines. But it is precisely he does not use any of the point systems described below in his evaluations, but awards one to five stars. Likewise, the well-known wine author Hugh Johnson uses his own scheme with 12 levels. Besides theoretical knowledge, the following skills are required: Smell sharpness, discrimination and memory, concentration and objectivity. The perception threshold plays an important role. This is the limit in the mg/l range and lower, from which a substance can be identified and named.

Professor Emile Peynaud (1912-2004), who is one of the most famous tasters, writes the following in his standard work "Hohe Schule für Weinkenner", which has been published several times: The statement that something is sweet is an objective statement; it characterizes the product in question. To say, for example, that a cup of coffee is sufficiently or not sufficiently sweet; is a subjective statement; it is personal; it depends on a person's drinking habits and taste. However, to say that sugar tastes unpleasant; that one detests anything sweet is an affective opinion

The professional taster must be able to switch off his affectivity. He should not say whether he likes a wine or not. You don't want to know that about him. He must study the wine, describe it, assess its good or bad organoleptic characteristics and draw conclusions. These will be subjective, but they must not be based on personal preference, at least as little as possible. This is the great and decisive difference between the untrained wine drinker and the untrained wine drinker whose judgement is purely affective"

different assessment results

Nevertheless, even with absolute specialists, the evaluation of the same wine can differ, although this usually (if at all) only accounts for a few points. If there are several scales, even from different manufacturers, one can very well assume that when weighing an object up to at least a tenth of a gram, the result will be the same. After all, the scales are all calibrated. But this cannot be the case with humans, because palate and tongue as well as experience and preferences of different people are certainly not identical. A different result is therefore not inevitable, but not surprising either.

As an example of an extremely varied evaluation, the grading of Château Pavie's red wine of the 2003 vintage is often mentioned. Robert Parker awarded 96/100 points and Jancis Robinson 12/20 points. Below is the formula for the conversion of points between the 20 and 100 point system. Accordingly, the 12/20 points of Robinson correspond to 76/100 points - that means a "simple wine without faults". The 96/100 points from Parker mean a "great wine of world class". However, the two have not tasted from the same bottle. Two bottles may very well have differences in quality for different reasons, which is called bottle variance.

As a rule, wine evaluations have no scientific validity. If the same judges and the same wines were to repeat the competition the next day, the result would not be completely different, but in all probability largely different scores. In the sense of a scientifically recognized result, however, they would have to be repeatable, i.e. at best completely identical. It can be assumed that the differences between two evaluation rounds are smaller the higher the knowledge, experience and professionalism of the tasters. See in this respect the result of a legendary international contest between France and California under Paris Wine Tasting.

Occasion for a tasting

One tastes a wine to determine its quality for various reasons. In the course of an official examination, professional control bodies, among others, determine whether the wine meets the legal requirements for wine. This is the case, for example, with the allocation of the official test number (Germany) and the state test number (Austria) for quality wines, where, in addition to the analytical test using chemical and technical aids, a sensory (organoleptic) test is also carried out by the sensory organs. Another reason may be a competition in which different wines are tasted, evaluated and awarded prizes according to the results. The third reason can be of a purely private nature. Either to educate oneself further, to enjoy wine with friends and talk about it or to find out the best value for money when buying wine. However, the criteria are very similar, in any case they must be precisely defined and known beforehand so that all tasters start from the same basis.

The best time for a tasting is in the late morning, because the human body or the sensory organs are most receptive and "fresh". A cold, medication, spicy or strongly seasoned food, coffee, sour fruit, tobacco, chewing gum and perfume are all disturbing or can have a negative influence on a tasting. The room should be well lit and free of foreign odours. The ideal room temperature is around 20 °Celsius. A white table background for checking the colour is required. The rule of thumb for the order of different wines is: dry before sweet, young before old and lesser before great wines. As far as wine colour is concerned, the following rule of thumb applies: dry light white wines before heavy red wines, but young light red wines before extract-rich white wines. Since, for good reasons, swallowing is generally not done at professional tastings, suitable containers (spittoons) should be available. Between the wines, the taste buds should always be neutralized by drinking crackers and still water.

Procedure/processing

In addition to colour, odour and taste are important criteria for evaluation. For a long time it was considered that there are only four taste sensations perceptible by the tongue, namely bitter, sour, salty and sweet. Now officially the fifth is umami (fleshy) and the sixth is fatty. Odours are perceived olfactorically in the upper nasal cavity. However, two sensory systems are involved in olfactory perception. Besides the olfactory one, this is the trigeminal system. A strong restriction results with cold. One can recognize the taste, but not the smell. During normal breathing, only a small number of scents reach the receptors. Therefore one must "sniff" with the nose deeply but not too firmly in the glass.

As a result, the air glides faster through the nose and the flow to the receptors increases. Repeated sniffing is useless. The olfactory space is quickly enriched and needs at least two to three minutes for "regeneration". Therefore, the first impression is usually the best. When breathing out, the primary and secondary aromas are perceived through the nose, and when breathing in, the tertiary aromas. The tongue (taste) is far inferior to the only six directions of the nose (smell) with an estimated 10,000 perceptible scents. The smell and the taste interact and influence each other; a complex overall picture is created. It is not possible to differentiate exactly between the two senses. A large part of the impressions commonly referred to as the taste of a wine is perceived by the sense of smell.

In professional tastings, an otherwise anonymous wine is assessed under standardised conditions by independent, trained sensory experts, who are familiar with the geographical designation or origin, vintage, grape variety (if known), quality grade and possibly special oenological procedures (e.g. barrique ageing). In order to achieve the necessary significance, the wine evaluation must be carried out either by a sufficiently large panel of testers with at least five tasters or several anonymous repetitions in other groups. A scientifically proven statement with 97% accuracy can only be achieved with about 25 tasters/repeats. A layman cannot even begin to achieve all this.

Evaluation systems

For the verbal assessment - the wine address - a partly standardized terminology is used. For tasting, uncoloured, long-stemmed wine glasses with tulip-shaped goblets and stable feet should be used - there are special tasting glasses for this purpose. The glass is generally taken by the stem (never by the goblet) to avoid heating by hand. In this context the question of the required amount of wine per person also arises. As a rule, a 0.75 litre bottle is sufficient for 12 to 14 tasters, which is about 0.05 litres per person. Then there is also a small amount left over for any necessary subsequent tasting. There are different evaluation systems, but they are basically similar:

5-point scheme
Used for example for quality wine testing in Germany. See Official Test Number and German Wine Seal.

Symbols
In wine guides and magazines, additional categorization is often provided in the form of symbols such as bottles, grapes, stars, glasses, corkscrews, etc. The rating goes from 1 to 3, 1 to 4 or even 1 to 5. 1 to 3 wine glasses are awarded in the Italian wine guide Gambero Rosso, 1 to 3 stars in the French wine guide Hachette and 1 to 4 grapes in Gault Millau. In vintage tables, individual years (or their wine quality - separated by country and wine-growing region) are often classified with 1 to 5 stars.

20-point scheme
Is still the most common (in similar forms) in Europe. Among other things, this system is common for the allocation of the State examination number (Austria), as well as for the classification in Saint-Émilion (France).

50-point scheme
A rarely used variant of the 100-point system, in which the evaluation does not start at 51, but at 1.

100-point scheme
This internationally most widely used system became popular at the beginning of the 1980s through the wine critic Robert M. Parker (*1947). Above all, it is common and recognised overseas, but has also become internationally accepted. Its acceptance in the USA is also due to the fact that it corresponds to the grading system of high schools. Each wine gets 50 points from the start. A wine up to 75 points has a more or less pronounced wine defect. For certain faults, this is tolerated for simpler wines if the fault is less pronounced, but not for quality wines without exception. Only above this limit do the good qualities begin. The rarely awarded 100 points are reserved for very few "grandiose" wines, which are also called century wines. If you consider wines as a capital investment, for which there is a collector's scene, then you concentrate on top wines with at least 90 points.

The range of the individual stages from flawed to grandiose is applied somewhat differently by the individual wine critics. Today there are also different opinions about how strictly this system should be interpreted. For example, most users of this scheme have for several years now been experiencing a creeping upward shift in the scores, which leads to an unnatural compression of the system (one could also call this a pleasantness rating). At Wine Plus the original, strict version is applied, where the range of recommended wines already starts at 80 points.

Conversion 20 and 100 system
The lowest limit for a still drinkable wine is 70 points for the 100-point system and 10 points for the 20-point system. This means that levels 11 to 20 correspond to levels 71 to 100. Each point in the 20 point system above 10 points therefore corresponds to 3 points above 70 in the 100 point system. The conversion example at 17 points: 70 + (7 x 3) = 91. This also applies vice versa.

Evaluation criteria

The evaluation itself is based on at least three to six criteria. A common form is according to the five criteria of appearance (which, however, is distinguished by colour and clarity), smell, taste and overall impression. The table at the end shows an evaluation sheet in the 20-system, whereby the criteria can also be used or are valid for all other systems. Half or tenth points can also be awarded. It is advisable to enter the individual results and comments constantly in the form. This results in a total number of points according to the points system used. The five criteria in detail:

Colour - Clarity (max. 2 points each)
Most experts do not attach much importance to colour, as a deep dark red wine is "beautiful" but does not mean a statement about quality - laymen often rate this too highly. For many consumers, however, colour plays a very decisive role. An appealing colouring of a red wine leads to the fact that one is less critical with regard to the taste. However, age can be recognised by the colour; the outer edge is decisive. Old red wines have a brown hue. During ageing or bottle aging red wines become lighter, for white wines it is the other way round. One of the causes of red wine is that the anthocyanins (red colorants) are precipitated. But much more important than a beautiful colour is clarity and purity.

Cloudiness can indicate a wine defect. The surface must have a clean reflection and not appear stained or dull. However, a deposit in a red wine is nothing negative. For testing, tilt the glass so that the liquid level forms an "egg". Now hold the glass against a light with a bright (at best white) background. A flawless wine must be clear and a white wine must also be transparent.

As a rule, the colour is determined organoleptically by eye, i.e. without any aids. More rarely, this is also done by comparison with colour standards such as the colour spectrum of the French chemist Michel Eugène Chevreul (1786-1889), who divided the colours into 72 basic colours with 20 shades each. Although he never dealt with wine (but with the colouring of tapestries), his colour table was later also used to describe the colour of red wines. A third possibility is measuring by means of a spectrometer in the laboratory, which is the most objective and accurate way.

Odour (max. 4 points)
The glass is tilted in the shape of a 6 or 9 so that the wine swings to just below the rim. With the nose deep in the glass the smell is checked and this is repeated several times. In the process, the grape variety can already be determined (at least for varietal and typical wines). Furthermore, one can conclude whether the wine is young, mature, acidic or with residual sugar.

Taste (max. 7 points)
Take a small sip, inhale at the same time and let the wine roll over your tongue. The taste usually confirms the olfactory sensation. Now the total extract of the wine can be analysed in its full range. The human tongue picks up very specific sensations at different points, but the areas are not clearly defined, but rather fluid:

• Tip of the tongue: residual sugar (dry to sweet)
• front edges of the tongue: saltiness
• middle tongue edges: acids (fresh, mild, acidic, acidic)
• rear, medium range: tannins (tart to bitter)
• rear area: umami (glutamate)

Overall impression (max. 5 points)
In summary, the overall impression (character) of the wine is assessed, taking all components into account. The scale ranges from disappointment to wine of the century. This concerns the general quality, the balance (balance, harmony), the typicality, the finesse, the finish, as well as the stage of development or the drinking maturity of the wine.

Tasting types

Which type of tasting is applied with which rules is determined by the objective:

• compare and identify for the purpose of identifying a particular wine or checking factors
• evaluate and classify for the purpose of official examinations or competitions
• determine and determine sensory perceptions for the purpose of addressing wine (description)

In order to check the objectivity and attention of the tasters, double tasting (the same wine twice) is also common, or pirates are infiltrated (for example, one Pinot Blanc among ten Rieslings). As orientation aids for the tasters there are the reference wine (wine type) and the level wine (evaluation scale). There are the following rules or techniques, some of which are used in combination:

Counter sample
In order to exclude the phenomenon of bottle variance or an unfair assessment by individual spoiled bottles at professional wine tastings, cross-checks are carried out using counter-bottles.

Re-tasting
Any wine tasting, however professional, can only be a snapshot of the current state of development. As a wine develops or changes during its life cycle, it is necessary to taste it again or even several times. See also under drinking maturity.

Tasting in pairs
In this frequent tasting (also in pairs) two wines are presented together in two glasses and tasted for comparison and evaluation. There are the variants that only one wine, both wines or none of the wines are known. The aim here is to determine the differences between two wines. This can be concretised to the questions "which wine is sweeter", "which wine is more acidic", "which wine is more aromatic" or "which wine pleases better". Other forms are the "Duo-Trio-Test", in which the same wine is contained and identified in two of three glasses, and the triangular test.

Open tasting
The wines served in unobscured bottles are well known.

Half-blind tasting
It is known which wines are involved, but not in which carafe or glass they are contained. This form is often used at wine seminars and is also suitable for private tasting.

Blind tasting
In this mostly common form, there is certain information depending on the tasting or comparison target. This can be common parameters such as grape variety, vintage or origin, but in no case information such as brand names that point to the producers. In order to guarantee the highest degree of objectivity, appropriate precautions are necessary (see in the main keyword).

Horizontal tasting
Wines of one vintage of a certain growing region are tasted.

Vertical tasting
During this event different vintages of wines from one producer are tasted

Special forms
Depending on the objective, there are also special tasting types. During the examination for the Master of Wine, the grape variety, the origin and the vintage must be found out. At first glance, the grape variety seems to be the easiest, but according to tests carried out by professional tasters at the University of California, this is not always the case. Certain grape varieties, such as Muscatel, were well identified because of the typical Muscatel character of the variety, at 60%, but the success rate for Cabernet Sauvignon was relatively low, at 40%. There were better results for the origin, because certain growing areas are particularly characteristic. In the vintage, colour and maturity of the wine are the most important recognition factors.

A new analytical method is increasingly used for the sensory evaluation of wines. The "Quantitative Descriptive Analysis" or "Profile Analysis" method, which has long been common in the food industry, allows for a more objective evaluation according to precisely defined criteria. The result is displayed graphically with a polar diagram. See QDA (Quantitative Descriptive Analysis).

Sources/Rights of the images

Wine glass: By Mick Stephenson mixpix, Own work, CC BY-SA 3.0, Link
Tongue (edited): Copyright: Peter Hermes Furian
Receptor (edited): By NEUROtiker - Own work, CC BY-SA 3.0, Link
Smell: From Chabacano - from Brain and mouth anatomy,
by Patrick J. Lynch, medical illustrator, CC BY-SA 2.5, Link