The present study aims to establish the influence of some technological  and agricultural factors on the quality of the red wines of the variety (Vitis vinifera L.) Bobal in traditional culture conditions in rainfed of vineyards in the region of  Requena. All the experiments were carried out in the field and cellar pilot of the School of Viticulture and Enology of Requena (Diputación de Valencia). 

	The excessive vigour lengthens the  phenological cycle of the vineyard, increases the speed of growth and the weight of wood pruning. For against water stress reduces photosynthesis, favors stop growth, limits the size of the berries and stimulates sėntesis of phenolic compounds. A moderate water deficit stress can be conducive to the potential of the wine red varieties. To find the regime hėdric of the variety, has been measured leaf water potential in the years 2003 2004, trying to find possible differences over other varieties such as Syrah, Tempranillo, Cabernet Sauvignon, Chardonnay and Parellada, grown in the same environment.

	The predawn leaf water potential (?b) measured with the pressure chamber found no significant differences, with average values that did not exceed the -0.35 MPa for any of them, which shows a lack of water stress during the period studied. However, the midday leaf water potential (?md) indicates significant differences for the year 2003, and is significant the fact that the variety Bobal has the potential less negative during the two years of study. 

	Most of the wines of the variety Bobal always been characterized by its low alcoholic strength, high acidity, intense color and hardiness of its tannins. If you go to other parameters different than sugar content and acidity, the optimal time to harvest always assumed one of the most difficult tasks in establishing quality wines. Therefore, in this paper we have made vintages with different states of maturity trying to determine the best time to do it. Together analyzed the phenolic ripeness of the grapes in order to establish possible wine-grape relationships. To optimize the extraction of polyphenols and potential varietal grapes Bobal was submitted to the technique of cold maceration prefermentative, vinifications were conducted in parallel with different times of maceration. 

	The grapes more mature produced wines with more polymerized tannins, lower index of gelatin and produced wines with more intense aromatic and olfactory characters. The cold maceration prefermentative provided more colored wine, with less astringency, lower polymerization and better taste quality.

	Prolonging the mashing time was a performance in line with expectations, with an increase of tannins, polyphenols and degree of polymerization. The sensory analysis offered no significant differences, although tasters showed a greater tendency toward longer macerated wines.