TY - JOUR T1 - A Test of Fractional Addition of Wine Spirits to Red and White Port Wines JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 129 LP - 136 DO - 10.5344/ajev.1963.14.3.129 VL - 14 IS - 3 AU - V. L. Singleton AU - J. F. Guymon Y1 - 1963/01/01 UR - http://www.ajevonline.org/content/14/3/129.abstract N2 - 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. ER -