Sensory attributes of wines made from vines of differing phosphorus status

Abstract

Aim: The implications of water and nutrient deficiencies for photosynthesis, dry matter production, and yield have been well documented. However, whereas multiple studies show that water deficits affect grape and wine quality as well as wine sensory characteristics, the corresponding implications of manipulating vine nutrient status through fertilizer additions remain largely unexplored. Methods and results: In this study, phosphorus (P) fertilizers were applied to P-deficient vineyards of Cabernet Sauvignon, Chardonnay, and Chenin blanc growing in rhyolite, granite, and schist derived soils. Bloomtime leaf lamina P levels, basic soil chemical characteristics, juice P, and wine chemical parameters were measured after harvest. A highly sensitive protocol for sensory evaluation was used to test the wines made from the treated and untreated grapes for differences in wine appearance, flavor, aroma, and taste. All P additions were effective in rapidly increasing both vine P status and P in the harvested juice. In Cabernet Sauvignon vines growing on rhyolite, juice P was linearly related to vine P status compared to a non-linear accumulation of juice P in Chenin blanc vines growing on an calcium-rich schist soil. Soil CEC and Ca levels were both higher in the schist derived soil than in the rhyolite or granite soils, indicating a possible association of P release with soil parent material. Differences were detected in appearance, flavor, aroma, and taste in wines made from all three varieties on all three sites. Also, increasing vine P status increased the concentration of anthocyanins and soluble phenolics in the wines, and reduced fermentation time in the Cabernet Sauvignon. Conclusions: The results of this study show that vine P nutrient status can be manipulated by the grower across different soil types. Vine nutrient status has also been shown to significantly affect vine bud fertility, photosynthesis, dry matter and fruit production, and grape and wine chemical parameters. However, there is a lack of data describing the effect of manipulating vine nutrient status through fertilizer additions on the resulting wine sensory profile. Our results show that vine P status can influence the sensory attributes of wines. Significance and impact of the study: The results of this study and earlier work with vine water status identify two vineyard sources of variation in wine sensory attributes that occur both naturally and can be manipulated by the grower across different soil types.

Keywords

• grapevine
• plant nutrition
• phosphorus
• soil chemistry
• wine sensory