This dataset contains information about Portuguese white variants of “Vinho Verde” wine. It includes 4898 observations of 12 features. 11 of the features are chemical variables (independent variables), and the other feature is wine quality (dependent variable), a subjective measure that is the median of the opinions of three wine experts. Specifically, the features are:
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fixed acidity: most acids involved with wine or fixed or nonvolatile (do not evaporate readily)
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volatile acidity: the amount of acetic acid in wine, which at too high of levels can lead to an unpleasant, vinegar taste
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citric acid: found in small quantities, citric acid can add ‘freshness’ and flavor to wines
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residual sugar: the amount of sugar remaining after fermentation stops, it’s rare to find wines with less than 1 gram/liter and wines with greater than 45 grams/liter are considered sweet
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chlorides: the amount of salt in the wine
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free sulfur dioxide: the free form of SO2 exists in equilibrium between molecular SO2 (as a dissolved gas) and bisulfite ion; it prevents microbial growth and the oxidation of wine
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total sulfur dioxide: amount of free and bound forms of S02; in low concentrations, SO2 is mostly undetectable in wine, but at free SO2 concentrations over 50 ppm, SO2 becomes evident in the nose and taste of wine
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density: the density of water is close to that of water depending on the percent alcohol and sugar content
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pH: describes how acidic or basic a wine is on a scale from 0 (very acidic) to 14 (very basic); most wines are between 3-4 on the pH scale
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sulphates: a wine additive which can contribute to sulfur dioxide gas (S02) levels, which acts as an antimicrobial and antioxidant
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alcohol: the percent alcohol content of the wine
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quality: discrete score between 0 (worst) and 10 (best).
(These descriptions have been taken from reference 1.)