Improving Winemaking using Data

We explored red wine data using R to find statistical correlations between different variables and wine quality. The goal was to find some variables that could be tuned to obtain the highest quality wine possible.

Structure of the dataset

• X: whole number, unique for each observation (Removed).

• fixed.acidity: non-volatile acids found in wines, the most common are tartaric, malic, citric and succinic (as tartaric acid in g/L).

• volatile.acidity: largely acetic acid, linked to the vinegary taste (as acetic acid in g/L).

• citric.acid: found in small quantities, typically 1/20 of the tartaric acid concentrations (in g/L).

• residual.sugar: the sugar that remains in wine after fermentation completes (in g/L).

• chlorides: the amount of salt (as sodium chloride in g/L). There are legal limits for chloride content in wines, but it varies widely from country to country (i.e. 0.606 g/L of sodium chloride for Australia while the same limit is set at 0.06 g/L in Switzerland).

• free.sulfur.dioxide: SO2 [molecular] + HSO3 [bisulfites] + SO3 [sulfites]. It is the buffer against microbes and oxidation (in mg/L)

• total.sulfur.dioxide: free sulfur dioxide + bound sulfur dioxide [sulfites attached to either sugars, acetaldehyde or phenolic compounds] (in mg/L)

• density: mass divided by volume, the density of wines are close to that of water (in g/cm3)

• pH: -log10 of the activity of the hydrogen ion, it ranges from 0 to 14. (Zero is the most acidic, 7 is neutral, and 14 is the most basic); pH values for wines are typically between 3 and 4.

• sulphates: The concentration of sulfates. Sulfur dioxide, upon oxidation, is converted into sulfate (as potassium sulfate in g/L)

• alcohol: the amount of alcohol in % vol. For wines, it varies in a wide range, between 5.5% (Moscato d’Asti ) up to 21% (fortified wines).

• quality: a whole number to qualify the wine. It ranges from zero (bad) to ten (excellent), it is a subjective measure. For this dataset, it was the median of blind testing of at least three different experts for each sample.

Files

• RedWine.Rmd
• Redwine.htlm
• References.txt
• WineQualityReds.csv (dataset)