84 R. Peinado and J. Mauricio
storage in cellars at temperatures from 7◦C in winter to 17◦C in summer, and
60–80% relative humidity, for 6 years and 3 months. In this way, a yeast film
develops on the surface of the wine that alters its sensory properties. Thus, the
wine acquires a typical golden yellow colour and anacetaldehyde concentration of
600–700 mg/L (Pham et al. 1995).
3B.1.1 The Significance of Roc ́ıo in the Biological Aging Process
Recently, the effect ofroc ́ıoin the different scales of acriadera and solerasystem
and that on wine uniformity during the aging process have been examined (Berlanga
et al. 2004a, 2004b).
The effect ofroc ́ıocan be exposed by using a principal component analysis with
the contents in compounds closely relatedto yeast metabolism (e.g. acetaldehyde,
acetic acid, ethanol, glycerol, L-proline) as predictor variables.Roc ́ıohas signif-
icant effects on the scales containing the young and medium-aged wine (namely
the fourth, third and secondcriadera). On the other hand, it has little effect on the
firstcriaderaor thesolera, which contain the oldest wine (Fig. 3B.2). This can be
ascribed to the biological activity of the yeasts at these two stages - the last in the
process - being weaker than in the previous ones and physico-chemical processes
prevailing over it as a result (Berlanga et al. 2004b).
A similar effect is observed when one compares the point immediately afterroc ́ıo
with that seven days later. Thus, blending has a significant effect on the third and
secondcriadera, but not on the fourth - possibly because it receives younger wine
each year and its contents are less uniformas a result. However, the analysis of each
05101520254th
CRIADERA3rd
CRIADERA2nd
CRIADERA1st
CRIADERASOLERAF
(ethanol,aceticacid
, glycerol,acetald
ehyde, L-proline)Just after rocio
Seven days after rocioFig. 3B.2Effect of theroc ́ıoon the compounds highly related with yeast metabolism during the
biological aging.aJust afterroc ́ıo.bSeven days afterroc ́ıo