The Effect of Desiccation Spray on Ripeness in Chambourcin (2016)

This study examines the impact of a desiccation spray on the chemical and sensory profiles of Chambourcin grapes and wine. One block of Chambourcin was divided so that one section of fruit was sprayed with a potassium bicarbonate desiccant, and another section was not sprayed. The desiccated fruit was sprayed at the beginning of veraison and then weekly for a total of four sprays over four weeks. The fruit was harvested and processed on the same day, and all treatments between the fruit were identical. The desiccation treatment slightly concentrated berry components, although not many differences were found in wine. The desiccation treatment, however, lowered the color intensity and slightly lowered the tannin and anthocyanin content in the wine. Other parameters were not greatly affected. At one tasting, the wines were found to be significantly different (p<0.05), and in general there was a preference for the wine made without desiccation. At another tasting, there was no significant difference between wines, and no major preference trends. More studies on desiccation across vintages would be beneficial to further elucidate the impact of these treatments in Virginia.

Read Full Report (PDF)

The Effect of LalVigne Foliar Spray on Chambourcin (2016)

This study examines the impact that LalVigne Foliar Spray (ScottLabs) has on the ripeness of Chambourcin grapes. Lalvigne was sprayed at 5% veraison and then 7-9 days later on a 2 acre parcel of Chambourcin at the recommended rate. Control and treatment grapes from the same block were harvested and processed on the same day, fermented separately as 1.5 ton lots in T Bins, and all other treatments between fermentations were kept the same. A third treatment was also added, were 75 pounds of Tannat skins were added to LalVigne-treated grapes at the beginning of fermentation. Although ripening kinetics between each treatment were similar (data not shown), anecdotally, the sprayed berries exhibited more color development. Juice from LalVigne-treated grapes exhibited higher nitrogen numbers (except lower ammonia). Wine produced with Tannat skins added had lower alcohol and pH (58% increase in proton concentration). In general, grapes treated with LalVigne showed increased color intensity and increased amounts of phenolic compounds. The sprayed grapes showed a large increase in Malvidin glucoside but a slightly lower count of monomeric and total anthocyanins. Tannat skins added to the LalVigne sprayed wine showed a smaller increase in color intensity, a larger increase in catechin, epicatechin, gallic acid, and tannin, and a decrease in anthocyanin content. For the triangle test, of 21 people who answered, 9 people chose the correct wine (43%), suggesting the wines were not significantly different. In general, people who answered correctly had a slight preference for the sprayed wine, but this preference was very weak. Descriptive analysis did not show many trends between wines. The control tended to have slightly lower Overall Aromatic Intensity to the sprayed wines, and the wine with Tannat skins seemed to have higher Fruit Intensity. The LalVigne spray wines tended to have slightly higher Herbaceous/Green scores, except for the wine with Tannat added.

Read Full Report (PDF)