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November 2016 WINES&VINES 97 PRACTICAL WINERY & VINEYARD GRAPEGROWING grapes on own roots, or grafted to Ramsey, 1103 Paulsen, 140 Ruggeri and 101-14 root- stocks, positive linear relationships (R 2 =0.9) were obtained between grape juice K concen- tration and grape juice total soluble solids. 21 Furthermore, the slope of the relationships was the same at both sites, despite large differences in electrical conductivity of the irrigation water, specifically 0.4 decisiemens per meter at one site (Koorlong) and 2.1 decisiemens per meter at the other site (Merbein). Using data for grape juice K and total soluble solids obtained at harvest for each Chardonnay and Shiraz trial at four sites in- volving vines on own roots or grafted to eight different rootstocks, strong positive correla- tions (R 2 =0.7) were obtained between the variables. 23 Both sucrose and K are trans- ported in the phloem to developing berries. 12 This close association between the variables is further evidence of a potential relationship during phloem loading and unloading. Wine color hue is positively correlated with wine pH The strong correlation between K and pH in grape juice and wine has been noted. As previ- ously reported by T.C. Somers, high wine pH has a negative impact on wine color. 18 Using Shiraz wine data from the trials at four sites, where wine was made using fruit from own- rooted vines and from Shiraz grafted to five different rootstocks, wine color hue was posi- tively correlated with wine pH. 23 Low color hue means a brighter wine, conversely, a higher color hue with higher wine pH means less bright wines. Similar observations were made by H. Gong et al. 6 Distribution of K in grape berries When examined in terms of total berry K con- tent, the percentage of total berry K in skins has been found to be similar to the percentage of total berry K in pulp, with only a small per- centage of total berry K in seeds. For example, for the grape varieties Mus- cat Gordo Blanco, Shiraz, Riesling, Cabernet Sauvignon and Chardonnay, all grown on their own roots at Loxton, South Australia, the mean percentage of total berry K content in skin, pulp and seed was 43%, 50% and 7%, respectively. 20 Wine color hue was positively correlated with wine pH. Low color hue means a brighter wine; conversely, a higher color hue with higher wine pH means less bright wines. NOW AVAILABLE Powered by BREWEROMS A unique online system to locate, contact and sell to U.S. beer producers. The Wines & Vines Brewer Online Marketing System (BOMS) is a web-based system that allows you to search more than 4,300 North American breweries by specific criteria, and export data into custom reports. ORDER TODAY! winesandvines.com/boms