Potassium concentration and pH inter-relationships in grape juice and wine of Chardonnay and Shiraz from a range of rootstocks in different environments

作者：Walker R R^*; Blackmore D H

来源：Australian Journal of Grape and Wine Research, 2012, 18(2): 183-193.

DOI：10.1111/j.1755-0238.2012.00189.x

• grape
• H
• hue
• K
• pH
• wine

Background and Aims: pH adjustment during winemaking is a significant cost to the Australian wine industry. This study addresses potassium (K+) concentration and pH inter-relationships in grape juice and wine of Chardonnay and Shiraz. Methods and Results: Chardonnay and Shiraz on own roots, and on Ramsey, 1103 Paulsen, 140 Ruggeri, K51-40, Schwarzmann, 101-14, Rupestris St. George and 1202 Couderc were compared at Koorlong and Merbein (Victoria), and Padthaway, Nuriootpa and Rowland Flat (South Australia). Petiole K+ concentrations at flowering were a poor indicator of grape juice and wine K+ concentrations. The concentration of H+ ions in grape juice and wine decreased as K+ concentrations increased resulting in increased pH. The relationship between H+ and K+ concentrations was linear for Chardonnay but exponential for Shiraz, where K+ concentrations were higher. Wine K+ and grape juice K+ concentrations exhibited a positive linear relationship, with slope for Chardonnay about half that for Shiraz, indicating a net loss of K+ between grape juice and wine of 58% for Chardonnay and 13% for Shiraz. Conclusions: The study has linked higher wine pH to both higher juice soluble solids and K+, and to poorer wine colour hue. Loss of K+ during fermentation and cold stabilisation appeared higher for Chardonnay than for Shiraz. Significance of the Study: Rootstocks that lead to lower K+ concentrations and pH in grape juice and wine are identified. Differences in the K+ concentration dynamics between grape juice and wine of Chardonnay and Shiraz are described and quantified.

• 出版日期2012
• 单位CSIRO