3A Sparkling Wines and Yeast Autolysis 63
The yeasts used in the second fermentation should also present a series of char-
acteristics such as fermentative activity at low temperature, resistance to ethanol and
to CO 2 pressure, flocculation potential etc. (Bidan et al. 1986; Mart ́ınez-Rodr ́ıguez
et al. 2001a).
3A.2.1.2 Secondary Fermentation and Aging in the Bottle
The bottles are kept in places specially furnished for the aging process. In this stage
the second fermentationoccurs, the CO 2 is formed and stabilized and the aging with
the yeast takes place.
3A.2.1.3 Riddling
In this step the bottles are subject to a stirring process so that the sediment moves up
to the bottle neck. This process was originally carried out with the bottles on desks,
turning them manually 1/8 of a turn for 15days, until they were finally perpendicular
to the floor. Now this system has been replaced by automated systems that can move
all the bottles simultaneously.
3A.2.1.4 Disgorging
Disgorging involves separating the winefrom the lees accumulated in the previous
step at the neck of the bottle. This deposit of lees is frozen by immersing the bottle
in a cryogenic bath. The bottle is then placed upside down, the cap is removed and
the pressure inside causes the frozen deposit to be expelled.
If incorporated or immobilised yeasts are used (Fumi et al. 1987; Godia
et al. 1991; Busova et al. 1994; Colagrande et al. 1994; Divies et al. 1994; Yokotsuka
et al. 1997; Martynenko and Gracheva 2003; Martynenko et al. 2004) or yeasts inside
a cartridge designed for this purpose called Millispark system are placed in the neck
of the bottle, the riddling is avoided and disgorging is facilitated.
3A.2.1.5 Addition of Dosage Liquor
During the disgorging step, some of the wine may be lost; this can be compen-
sated for by the addition of the “liqueurexpedition”, which may correspond to
the sparkling wine itself or to saccharose,grape must, partially fermented must,
or must with or without corrected concentration, the base wine or a mixture of these
products, with addition, where relevant, of distilled wines. In this way, the sparkling
wine can be given the desired degree of sweetness and a standard product can be
obtained, regardless of the vintage, standardizing each product. Finally, the bottle is
closed with the final cork, which is secured to the neck with a wire cap.