Our aim here is to study the sugar reduction in musts to obtain wines with a slight alcohol reduction
by nanofiltration. Specifically, sugar reduction is achieved by two successive nanofiltration steps. To test
the method, we have worked with two types of musts: a white must from Verdejo grapes and a red one
from Tinta de Toro grapes. The musts obtained from the nanofiltration treatment have been mixed with
untreated must or with the retentate of the first nanofiltration stage in a proportion adequate to reduce
the alcohol content of the resulting wines by 2◦.
To verify the effectiveness of the process, each of these musts has been fermented along with an
untreated control sample of the same must. The alcohol reduction in the wines has been satisfactory.
However, a slight loss in the color and aroma of some compounds has been detected.