3B Biologically Aged Wines 93
of organic acids (particularly lactic and succinic) increase with time (Usseglio-
Tomasset 1983; Mart ́ınez de la Ossa et al. 1987).
3B.3.7 Polyphenols
Flor yeasts have the ability to protect the wine from atmospheric air and retain the
compounds that lead to browning (Bar ́on et al. 1997; M ́erida et al. 2005). The total
polyphenol value is low and decreases with time during biological aging.
3B.3.8 Lactones
Wines aged under a flor film typically contain various compounds especially impor-
tant among which are lactones.Thus, solerone (4-acetyl--butyrolactone) abounds
infinoand Jura wines and has for years been deem one of the greatest contributors to
their aroma profiles (Augustyn et al. 1971; Muller et al. 1973). However, subsequent
studies have suggested that this lactone has no impact on wine aroma (Martin and
Etievant 1991).
Sotolon (3-hydroxy-4,5-dimethylfuranone) possesses a strong, typical odour rem-
iniscent of nut and curry with a very low perception threshold (10 g/L) (Pham
et al. 1995; Da Silva Ferreira et al. 2002). This lactone has been detected in Jura
(Dubois et al. 1976) andfinowines (Moreno 2005), and also in some botrytized
white wines (Guichard et al. 1997; Masuda et al. 1984). Sotolon is formed by
aldolization of -ketobutyric acid and acetaldehyde (Guichard et al. 1997; Pham
et al. 1995). -Ketobutyric acid results from the deamination of L-threonine by flor
yeasts. Some authors have associated it with yeast autolysis (Pham et al. 1995).
Its final content in wine depends on the aging time, but usually amounts to lev-
els in the region of 200 g/L (Dubois et al. 1976; Guichard et al. 1997; Moreno
et al. 2004)
Other lactones detected include -butyrolactone and pantonolactone (2,4-dihyd-
roxy-3,3-dimethylbutyrolactone), which is deemed typical of sherry wines. Both
have been associated with specific yeast races (Zea et al. 1995) and the aging time
(Cort ́es 2002).
Wines are biologically aged in old casks which, unlike those used for vintage
aging, are rarely emptied or scrubbed. As a result, biologically aged wines contain
minimal amounts of lactones from wood such as -methyl--octalactone (Chaton-
net et al. 1990) and only in the scales holding the oldest wine.
3B.4 Sensory Properties
In Montilla-Mories and Jerez winemaking regions there are fundamentally three
different types of white wines, namelyfino,amontilladoandoloroso, which are
obtained by using thecriaderas and solerasystem.