934 20 Alcoholic Beverages
In the production of Scotch grain whiskey the sac-
charified starch is distilled in continuous column
stills. The character of the distillate is neutral,
with less aroma than malt whiskey. In both Scotch
whiskey processes, the distillates, with about
63% by volume ethanol, have to be stored/aged
in order to develop their full aroma. This is
best achieved by aging in old sherry casks or in
charred casks. At the end of processing, the alco-
hol content is reduced to a drinkable level, about
Table 20.28.Odorants of whisky
Aroma substance Concentration (mg/l)
Malt whiskya Bourbon whiskybEthanol 316 , 000 316 , 000
2-Methoxyphenol 0. 025 0. 056
5-Methyl-2-methoxyphenol 0. 0019 0. 0011
4-Methyl-2-methoxyphenol 0. 01 0. 016
4-Ethyl-2-methoxyphenol 0. 017 0. 059
2-Methylphenol 0. 034 0. 003
4-Methylphenol 0. 017 0. 008
3-Methylphenol 0. 008 0. 004
4-Ethylphenol 0. 016 0. 166
3-Ethylphenol 0. 0033 n.d.
Eugenol 0. 027 0. 24
3-Methylbutanol 568. 1 1062. 1
2-Methylbutanol 194. 2 423. 8
2-Phenylethanol 11. 213. 87
Ethylbutanoate 0. 76 0. 55
Ethylhexanoate 2. 07 1. 99
Ethyloctanoate 12. 38. 35
Ethyl-2-methylpropanoate 0. 52 0. 13
Ethyl-3-methylbutanoate 0. 21 0. 052
(S)-Ethyl-2-methylbutanoate 0. 092 0. 030
(S)-Ethyl-2-hydroxy-3-methylbutanoate 0. 005 0. 003
(2S,3S)-Ethyl-2-hydroxy-3-methylpentanoate 0. 004 0. 003
3-Methylbutylacetate 4. 02 2. 59
2-Phenylethylacetate 4. 10 1. 94
Methylpropanal 1. 74 0. 23
3-Methylbutanal 0. 65 0. 34
Vanillin 0. 68 2. 13
(3S,4S)-cis-Whisky lactone 0. 39 2. 49
(3S,4R)-trans-Whisky lactone 0. 07 0. 34
γ-Nonalactone 0. 11 0. 12
γ-Decalactone 0. 010 0. 002
2,3-Butandione 0. 39 0. 033
(E)-β-Damascenone 0. 024 0. 011
(E)-2-Nonenal 0. 024 0. 009
(E,E)-2,4-Decadienal 0. 006 0. 039
1,1-Diethoxyethane 21. 86 15. 33
aSingle malt whisky from Scotland, stored for 8 years in an oak cask.
bAmerican Kentucky straight bourbon whisky, stored for at least 3 years in a charred oak cask.
43% by volume. Depending on the desired flavor
or current preferences, the malt whiskey might be
blended with grain whiskey (“blended whiskey”).
American whiskey is made from corn, rye or
wheat by saccharification with malt enzymes, fer-
mentation of the wort, followed by doubledis-
tillation in column stills and aging, usually in
charred oakwood casks. The corn distillate con-
tent of bourbon whiskey is at least 51% by vol-
ume and that of corn whiskey is at least 80% by