There are numerous terms used to describe the process of examining and evaluating wine through human ‘smelling and tasting’; a few examples include ‘degustation’, ‘verkosten’, ‘Weinprobe’ and ‘Weinverkostung’. This involves a sensory assessment of a wine’s organoleptic properties, accompanied by a descriptive explanation of the findings obtained, in accordance with established rules and criteria and using generally accepted and understandable terms (see ‘Wine description’ for further details).

Sensory & analytical assessment

At the relevant events, this is not carried out in a scientific-analytical manner using technical or other aids, but ‘solely’ through the senses – the eyes, nose, palate and tongue. This may then result in an assessment based on a points system using various methods. However, in addition to this, there are also ways of carrying out objective measurements through precise chemical analyses. These include, for example, the determination of alcohol content, total extract, residual sugar, acids, sulphur and other substances.

Factors influencing taste perception

There is the phenomenon of national preferences and aversions. Generally speaking, Austrians and Germans prefer wines with pronounced acidity, Italians prefer bitter wines, Americans prefer sweet wines and the French prefer astringent wines, although this should be viewed with caution. The lighting in a room also influences the taste of wine. Scientists at Johannes Gutenberg University Mainz found that wine tastes better under red and blue light than under green or white light. The study revealed that the test wine tasted approximately 1.5 times sweeter under red light than under white or green light. The fruitiness was also rated highest under red light.

Sensory neutralisation

As, for good reasons, wine is not swallowed during professional tastings as a matter of principle, suitable vessels (spittoons) should be provided. Since there are no nerves in the throat responsible for the sensation of taste and smell, this does not detract from a proper assessment. Although this is sometimes questioned by laypeople, it is possible to make a comprehensive assessment right through to the finish (aftertaste). Between wines, the taste buds should be neutralised repeatedly by eating crackers and drinking still water.

During extensive tastings, a so-called ‘recovery wine’ is occasionally used to reset the sensory perception after particularly heavy, sweet or high-alcohol wines.

The interplay of sensory evaluation and analysis

Nevertheless, we cannot do without a ‘subjective’ assessment involving sensory tasting by humans; rather, the methods complement one another and it is only when combined that they enable the fairest and most transparent assessment of the wine’s actual quality. A person can assess sensorially whether a wine tastes dry, semi-sweet or sweet, but can never determine exactly how many grams of sugar are contained in a litre of wine.

Limitations of analytical methods

Analytical testing, on the other hand, can measure chemical properties precisely, but it cannot capture individual perceptions, personal taste sensations or evaluations based on experience. Despite increasing technical capabilities, human sensory perception currently remains an indispensable part of wine assessment (this also applies to many other fields).

The process of a professional tasting

Professional tasters are, however, able to set aside such influencing factors and assess a wine ‘fairly’ and ‘objectively’ by being aware of their personal likes and dislikes and, as far as possible, disregarding them. This ability, however, can only be achieved through years of practice and experience. To eliminate influences from external circumstances, such as the lighting mentioned above, professional tastings take place in a sparsely furnished, neutral environment.

1=Émile Peynaud, 2 = Robert Parker, 3 = Jancis Robinson, 4 = Michael Broadbent, 5 = Hugh Johnson

Required skills

In addition to theoretical knowledge, the following skills are required: a keen sense of smell, the ability to distinguish and recall, the ability to concentrate, and the greatest possible objectivity. The perception threshold plays an important role. This is the limit, in the mg/l range and below, at which a substance can be identified and named.

Objectivity and subjectivity in wine tasting

Professor Emile Peynaud (1912–2004), one of the most famous wine tasters, writes the following on this subject in his seminal work *The Art of Wine Tasting*, which has been reprinted several times:

The statement that something is sweet is an objective statement; it characterises the product in question. To say, for example, that a cup of coffee is sweet enough or not sweet enough is a subjective statement; it is personal; it depends on a person’s drinking habits and taste. However, if one says that sugar tastes unpleasant; that one detests anything that is sweet, then one is expressing an emotional opinion.

The professional taster must be able to set aside their personal feelings. They should not say whether they like a wine or find it to their taste. That is not what is expected of them at all. They must study the wine, describe it, assess its good or bad organoleptic characteristics and draw conclusions. Although these conclusions will be subjective, they must not be based on personal preference – or at least as little as possible. This is the major and decisive difference compared to the untrained wine drinker, whose judgement is purely emotional.”

Standardised tasting

In professional tastings, an otherwise anonymous wine is assessed in a value-neutral manner under standardised conditions by independent, trained sensory evaluators, who are aware of its origin, vintage, grape variety (if known), quality grade and any special oenological processes (e.g. barrique ageing). To achieve the necessary statistical significance, the wine assessment must either be carried out by a sufficiently large panel of at least five tasters or through multiple anonymous repetitions, each time with different groupings. A scientifically valid conclusion with 97% accuracy can only be reached with around 25 tasters or repetitions.

Subjectivity of human perception 

Even among professionals, the rating of the same wine can vary, although this usually amounts to only a few points (if at all). This is not the case with machines; for example, with scales from different manufacturers, one can assume that weighing an object will yield the same result. This is because the scales are all calibrated and virtually identical in terms of their construction. However, this cannot be the case with people, as the palates and tongues, as well as the experience and preferences, of different individuals are certainly not the same. A differing result is therefore not inevitable, but nor is it surprising.

The influence of bottle variation

An example of an extremely divergent assessment is the rating of the 2003 Château Pavie red wine, which was awarded 96/100 points by Robert Parker and 12/20 points by Jancis Robinson (see below for the conversion between the 20-point and 100-point systems). Accordingly, Robinson’s 12/20 points equate to 76/100 points – which means a ‘simple wine without faults’. Parker’s 96/100 points denote a ‘great, world-class wine’. However, the two did not taste from the same bottle. Two bottles may well exhibit differences in quality for various reasons, a phenomenon known as bottle variation.

Limited reproducibility of wine ratings

As a rule, wine ratings have no scientific validity. If the competition were repeated the following day with the same judges and the same wines, the scores would not be completely different, but would probably differ to some extent. However, to be considered a scientifically recognised result, they would need to be repeatable – that is, ideally, completely identical. It can be assumed that the greater the tasters’ knowledge, experience and professionalism, the smaller the differences between two rounds of evaluation will be. See, in this regard, the legendary competition between France and California under ‘Paris Wine Tasting’.

The purpose of a tasting

Wine is tasted for various reasons to determine its quality. As part of an official assessment, professional regulatory bodies determine, amongst other things, whether the wine meets the requirements of wine legislation. This is the case, for example, when awarding the Official Test Number (Germany) and State Test Number (Austria) for quality wines, where, in addition to analytical testing using chemical and technical methods, a sensory assessment is also carried out using the senses.

Another reason may be a professionally organised competition, in which various wines are tasted, assessed and awarded prizes based on the results. The third...