The musts of two grape varieties (Seibel 2 and Seibel 10.096) raised in the State of S. Paulo were blended in different percentages to observe their influence on the wine quality. The variety Seibel 2 produces wines of very poor quality. A must composed of 50% Seibel 2 and 50% Seibel 10.096 produced a much better wine. The most remarkable improvement was obtained through the fermentation of a must composed of 70% Seibel 10.096 and 30% Seibel 2.