3A Sparkling Wines and Yeast Autolysis 67
Another of the variables studied was the effect of the second fermentation and
also of aging time. The second fermentation is the main factor responsible for the
reduced foaming properties of the base wine (Girbau-Sol`a et al. 2002; Hidalgo
et al. 2004), although during aging there is a reduction in foamability and an
increased persistence of the foam (Andr ́es-Lacueva et al. 1996b). Some authors
have reported that a peak in the foaming properties is reached during aging of
the sparkling wines in the presence of lees, but over prolonged time periods these
properties can diminish (Maujean et al. 1990; Pueyo et al. 1995; Andr ́es-Lacueva
et al. 1997).
Grape variety is another variable to be taken into consideration, since it can,
also, influence wine foaming properties. The wines made with the Chardonnay
variety have the best foamability, although worse stability times (Andr ́es-Lacueva
et al. 1996b, 1997). Of the varieties Xarello, Macabeo and Parellada, grape varieties
used to produce the Cava wines (sparkling Spanish wines made by the traditional
method in specific regions), the Xarello variety is the one that gives the best foam-
ing properties (Andr ́es-Lacueva et al. 1996a). Girbau-S `ola et al. (2002a, 2002b)
have studied the effect of using red wine varieties (Trepat and Monastrell) to make
base wines and sparkling wines, and obtained an improvement. Similar results were
obtained by Hidalgo et al. (2004) when they made sparkling wines with the Gar-
nacha grape variety.
The influence of harvest yield has also been studied and was found to have no
effect on foaming qualities (Pozo-Bay ́on et al. 2004), in spite of the findings in this
work that too large a harvest can significantly affect the sensorial quality of the
sparkling wine, producing wines of a poorer quality.
The use of yeast strains with a greaterautolytic capacity can help to achieve,
in sparkling wines, better foaming properties in a shorter time period (Nunez
et al. 2005). The effect ofBotrytis cinereaon the foaming characteristics of sparkling
wines has also been studied (Marchal etal. 2001, 2006; Cilindre et al. 2007). In these
works it can be concluded that this infection can cause a drastic reduction in wine
foaming properties, since it uses up the proteins in the medium.
3A.4 General Features of Autolysis
As described previously, during the elaboration of sparkling wines by the traditional
method, an aging process takes place that is closely associated with the sensorial
quality of the final wine. In fact, it is during this aging of sparkling wines that
yeast autolysis takes place, by which the yeasts release intracellular compounds
into the wine that can significantly alter its final composition (Charpentier and
Feuillat 1993).
Yeast autolysis could be defined as the hydrolysis of biopolymers under the
action of hydrolytic enzymes which releases cytoplasmic (peptides, amino acids,
fatty acids and nucleotides) and cell wall (glucans, mannoproteins) compounds
into the wine (Alexandre et al. 2006).Usually, autolysis takes place at the end