Φ, benzene ring.
FIGURE 2.4 Biosynthesis of higher alcohols, according to Ehrlich.
Higher alcohols are found in brandies after distilling and contribute to their specific characters. Distillation techniques have a major impact on their overall concentration.
2.2.3 Miscellaneous Alcohols
These molecules originate from grapes and are found in wines. One group consists of C6 alcohols, hexanols and hexenols from plant tissues, giving the herbaceous/grassy aromas so characteristic of wines made from unripe grapes (Volume 1, Sections 11.6.2 and 13.3.4).
Another of these compounds is 1‐octen‐3‐ol, with an odor reminiscent of mushrooms. Its presence in wine is due to the action of Botrytis cinerea on grapes.
Finally, terpene alcohols, the main components in the distinctive Muscat aroma, are described in full elsewhere (Section 7.2.1).
2.3 Polyols
Polyols are characterized by the presence of several hydroxyl radicals in the same linear or cyclic molecule. In general, an accumulation of hydroxyl radicals in a compound raises the boiling point considerably (Table 2.2) due to the large number of hydrogen bonds, as well as increasing its viscosity and anti‐freeze properties. Parallel increases are observed in solubility and sweetness. Sugars are good examples of polyols.
TABLE 2.2 Impact of the Number of Hydroxyl Groups on the Boiling Point of Alcohols
| Alcohols and polyols | Boiling point(°C) | |
|---|---|---|
| Ethanol | CH3−CH2OH | 78 |
| Ethyleneglycol | CH2OH−CH2OH | 198 |
| Glycerol | CH2OH−CHOH−CH2OH | 290 |
2.3.1 C3 Polyol: Glycerol
