The aging of whisky in charred oak barrels brings about a number of chemical changes that enhance its taste and darken its color. The following table shows the change in a whisky’s proof as a function of the number of years it is stored (159).
Age, x (years) Proof, y
0………………………..104.6
0.5……………………...104.1
1………………………..104.4
2………………………..105.0
3………………………..106.0
4………………………..106.8
5………………………..107.7
6………………………..108.7
7………………………..110.6
8………………………..112.1