A Test of Fractional Addition of Wine Spirits to Red and White Port Wines

¹ Department of Viticulture and Enology, University of California, Davis.

The hypothesis that the major effect of fractional addition of wine spirits, compared to single addition, is the result of heads reduction appears to have been verified by this research. Heads, as measured by volatile aldehyde, appear definitely undesirable at high levels in white port, and the quality of the white port as measured by this panel of judges was a function of the degree of heads reduction produced. The relationship between heads content and quality is less clear in ruby port, because the effect of heads on sensory properties was smaller than other factors in these experiments.