Central Virginia Cabernet Franc Terroir Investigation (2017)

The purpose of this study is to evaluate the difference in wine quality and chemistry based on vineyard site and winemaking style using Cabernet Franc grapes grown in and around the Monticello Wine Trail appellation. This purpose was achieved through comparing the impact of growing area on wine style (by comparing how wines from different vineyard sites taste when produced by the same winemaker) as well as comparing different winemaking stylistic impacts on grapes from different regions (by tasting grapes from the same region being produced by different winemakers). Three winemakers traded their grapes to each other and fermented each other’s grapes according to their own stylistic practices. The results of this study suggest that winemaking practices are able to substantially impact many of the vineyard effects on wine chemistry. Wines produced at Veritas tended to be positively correlated with Tannin and either negatively correlated to Total Anthocyanin, or not correlated with Anthocyanin (Veritas Winery Veritas Grapes). Wines produced at Early Mountain Vineyards, on the other hand, were generally correlated to Total Anthocyanins and negatively correlated to Tannin. Horton winery tended to produce wines which were in-between the Veritas and Early Mountain wines, in many of these regards. Overall, these results suggest that while vineyard site places some boundaries on the chemical qualities of wine, chemical qualities can be easily driven by winemaking practices. However, vineyard site tended to have the greatest impact on sensory characteristics. Early Mountain grapes tended to have more Herbaceous and Acidic qualities, and Veritas grapes tended to have higher Fruit Intensity and Astringency. Horton grapes tended to have higher Overall Aromatic Intensity. However, winemaking practices were able to alter these sensory characteristics in some cases, so that there was not a simplistic division of vineyard sites into certain flavor profiles. Most parameters were not dominated by either winemaking or vineyard site, but a mixture of both was seen. In the future, many more studies should be performed, with more statistical rigor.

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The Impact of Soil Conductivity on Petit Verdot Ripeness and Wine Quality in VSP Trellising (in collaboration with Bubba Beasley) (2017)

This study attempts to quantify the impact of soil conductivity on VSP-trained Petit Verdot juice and wine chemistry, as well as on the sensory qualities of wine. Soil conductivity was determined by EM mapping performed by Bubba Beasley, in order to find areas of low and high conductivity within the vineyard block. The low conductivity soil had a low rock content, and the high conductivity soil had high rock content (75%, shale). Then, fruit from each conductivity region was harvested on the same day but kept separate and destemmed into two T Bins: One for low conductivity fruit, and the other for high conductivity fruit. Fermentations were punched down twice per day, and all other treatments between wines were identical. Yield and viticultural parameters suggest an ESVC:CW index of 1.2 for both the low conductivity and high conductivity. Acidity and potassium was higher in the high conductivity juice. Indeed, soil pH was found to be negatively correlated to petiolar potassium and positively correlated to fruit pH. Petiolar potassium was also found to be positively correlated to juice potassium. Wine made from higher conductivity grapes had higher acidity and lower potassium. The high conductivity treatment had slightly lower anthocyanin and tannin measures. These results, overall, suggest that the lower conductivity wine had generally “riper” characteristics. These results would not be expected, as the higher conductivity soil (with higher rock content) would be expected to have less total available water in the soil for the grapevines to use. It would be more expected, therefore, that the high conductivity vine would have had less water, and thus potentially more “ripe” chemistry characteristics. Overall, the wines were not found to be significantly different at tastings. There may have been a slight preference for the low conductivity wine, but if so it was very weak. There were slight tendencies for the high conductivity treatment to have higher Acidity and Bitterness, and slightly lower Body. These further suggest a less “ripe” wine was produced at the high conductivity block. This study should be repeated over multiple vintages in order to determine whether these results are replicable.

This study should be read with its companion study in Ballerina trellising.

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The Impact of Soil Conductivity on Petit Verdot Ripeness and Wine Quality in Ballerina Trellising (in collaboration with Bubba Beasley) (2017)

This study attempts to quantify the impact of soil conductivity on ballerina-trained Petit Verdot juice and wine chemistry, as well as on the sensory qualities of wine. Soil conductivity was determined by EM mapping performed by Bubba Beasley, in order to find areas of low and high conductivity within the vineyard block. The low conductivity soil had lower soil rock content (10%, channers), and the high conductivity soil had higher rock content (50%, shale). Then, fruit from each conductivity region was harvested on the same day but kept separate, and destemmed into two T Bins: One for low conductivity fruit, and the other for high conductivity fruit. Fermentations were punched down twice per day, and all other treatments between wines were identical. Average berry weight and cluster weight were slightly higher in the high conductivity treatments. Yield and viticultural parameters suggest an ESVC:CW of 1.7 and 1.9 for the low conductivity and high conductivity, respectively. Juice Brix and potassium was lower, and acidity and nitrogen were higher in the high conductivity treatment. These differences transferred through to wine chemistry. The high conductivity treatment seemed to have lower levels of phenolic compounds, and lower color. These results, overall, suggest that the lower conductivity wine had generally “riper” characteristics. These results would not be expected, as the higher conductivity soil (with higher rock content) would be expected to have less total available water in the soil for the grapevines to use. It would be more expected, therefore, that the high conductivity vine would have had less water, and thus potentially more “ripe” chemistry characteristics. Overall, these wines were not found to be significantly different in triangle testing. No preference trends could be seen. Additionally, descriptive analysis results were inconsistent between tastings, and no general trends can be seen except perhaps that the high conductivity wine had slightly lower Body. In the future, this study should be repeated over multiple vintages, on different grape varieties, and at different sites.

This study should be read with its companion study in VSP trellising.

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Influence of Soil Conductivity on Vineyard Maturity in Cabernet Franc (2014)

Soil electromagnetic conductivity may give information regarding soil drainage, salt composition, nutrient density, and texture.  High electrical conductivity correlates to high cation exchange capacity, and is often found in drier soils (due to less salt leaching) or clay soils.  Electromagnetic conductivity soil mapping was conducted on different vineyard blocks, and Cabernet Franc blocks of low and high conductivity were harvested separately but on the same day and processed identically.  There were no chemical differences between wines, and sensory results were not significant.  However, the trace metal content of the wines were different.

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Influence of Soil Conductivity on Vineyard Maturity in Merlot (2014)

Soil electromagnetic conductivity may give information regarding soil drainage, salt composition, nutrient density, and texture.  High electrical conductivity correlates to high cation exchange capacity, and is often found in drier soils (due to less salt leaching) or clay soils.  Electromagnetic conductivity soil mapping was conducted on different vineyard blocks, and Merlot blocks of low and high conductivity were harvested separately but on the same day and processed identically.  Although laboratory analyses showed little differences between the wines, sensory analysis revealed significant differences between these wines, with a preference for wines made from high conductivity soils.

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