Food Chemistry

20.2 Wine 925

Fig. 20.7.Monoterpenes in wines from the grape cultivar “White Riesling” and in wines from other grape cultivars
which are also sold as “Riesling” (according toRappet al., 1985). A: White Riesling (Rheinpfalz), B: White
Riesling (France), C: Welschriesling (Austria), D: Welschriesling (Italy), E: Laski Rizling (Yugoslavia), F: Hunter
Valley Riesling (Australia), G: Emerald Riesling (USA). Monoterpenes: 1 trans-furan linalool oxide, 2 cis-furan
linalool oxide, 3 neroloxide, 4 linalool, 5 hotrienol, 6 α-terpineol, 7 not identified, 8 trans-pyran linalool oxide,
9 cis-pyran linalool oxide, 10 3,7-dimethylocta-1,5-trans-dien-3,7-diol, 11 3,7-dimethyl-1-octen-3,7-diol

Table 20.24.Aroma defects in wine

Aroma defect Key aroma substances Cause

Mousy note 2-Ethyl-3,4,5,6-tetrahydropyridine,
2-acetyl-3,4,5,6-tetrahydropyridine,
2-acetyl-1,2,5,6-tetrahydropyridine

Lactic acid bacteria in combination

with yeasts

of the genusBrettanomyces

Strawberry note 4-Hydroxy-2,5-dimethyl-3(2H)-furanone
(HD3F):>1500 μg/l

Characteristic of the cultivar

Medicine note 4-Vinylphenol +
4-vinylguaiacol:>800 μg/l

Climate, microbiological processes

Medicinal, woody,
smoky, horse sweat

4-Ethylphenol +

4-ethylguaiacol:>400 μg/l

Climate, microbiological processes

Kerosine/petrol note 1,1,6-Trimethyl-1,2-dihydro-naphthaline
(TDN):>300 μg/l

Southern climate, excessively high
carotinoid concentration in Riesling
“Boeckser” Hydrogen sulfide Fermentation

Cork taste/musty note 2,4,6-Trichloroanisole, geosmin,
2-methylisoborneol, 1-octen-3-one,
4,5-dichloroguaiacol, chlorovanillin

Contamination during wine storage

Untypical aging note
(naphthaline note, fox
note, hybrid note)

2-Aminoacetophenone:> 0 .5μg/l Stress reaction of the vine

The so-called “boeckser” is caused by the smell
of hydrogen sulfide. The very unpleasant, rot-
ten and yeasty “boeckser” (= mercaptan) odor is
most objectionable and lingers for a long time.
It is due to ethylthiol, which can be removed
by activated charcoal. The volatile sulfur com-

pounds originate from sulfite which is reduced

to H 2 S by yeast, later reacting with ethanol to

form ethylthiol. Additional wine taste defects are

the odd and disagreeable cork tastes which is

due to the formation of the odorants listed in Ta-

ble 20.24 and 2,4,6-trichloroanisole. Above con-