The Impact of Adding Viognier Skins to Petit Verdot Fermentations (2017)

This study examines whether adding Viognier skins to Petit Verdot fermentations alters the chemical and sensory qualities of the wine. The goal of adding Viognier skins was to mellow out some of the harsher characteristics of Petit Verdot. Petit Verdot grapes were crushed and split into two separate T Bins. To one bin, 10% w/w of Viognier skins were added (the skins were received a couple of days before processing Petit Verdot and were refrigerated prior to addition). An attempt was made to sort stems out of the Viognier skins. The other bin did not receive Viognier skins. All other treatments between wines were identical. Volatile acidity was slightly higher in the wine with Viognier skins. Color, and several phenolic parameters, were reduced in the Viognier skins treatment. For the triangle test, of 7 people who answered, 2 people chose the correct wine (29%), suggesting that the wines were not significantly different. No preference trends were discernible. For the descriptive analysis, there were no strong trends for the descriptors used in this study. The wines with Viognier skins had a slight tendency towards higher Bitterness, and perhaps higher Astringency. Although the chemistry suggests that the Viognier would reduce the tannic character of the wine, the sensory results suggest otherwise. More studies are needed in order to more fully evaluate the impact of adding white grape skins to red wine fermentations on chemical and sensory qualities.

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The Effect of Different Aging Vessels on the Sensory Qualities of Viognier (2016)

This study examines the effects of aging Viognier wine in concrete eggs, stainless steel barrels, and acacia barrels on the chemical and sensory qualities of Viognier. One lot of Viognier wine was split into these different aging vessels after a week of fermentation. The wine was aged in these vessels for approximately four months. No chemical differences could be found between wines, except that acacia barrels exhibited the lowest levels of dimethyl sulfide. Aging in acacia barrels tended to reduce Fruit Intensity and Overall Aromatic Intensity and increase Yeast Character. Stainless steel and concrete egg aging tended to help maintain Fruit Intensity and Aroma. In general, aging in acacia barrels was least preferred compared to other treatments. More studies on these different aging vessels should be performed, perhaps with different aging times and types of wine.

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Low Sulfur Dioxide Winemaking with Viognier (2015)

Viognier was fermented using traditional winemaking and sulfur dioxide-free winemaking at the pressing stage.  Sulfur dioxide was used after the completion of alcoholic fermentation.  The wine produced had very little chemical differences, except that the sulfur dioxide-free wine had much more malic acid.  The traditional wine in general had a slightly higher microbial presence.  Although sensory differences were distinguished between the wines, there was no sensory preferences between the wines.

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Glutathione Addition in Viognier – FreshArom (2014)

This study compares the chemical and sensory aspects of Viognier wines whose juice had been treated with FreshArom (Laffort), a glutathione product.  Glutathione is thought to help prevent oxidation in juice.  No chemical differences were observed in the wines except that titratable acidity was higher in the wine treated with FreshArom.  Significant sensory differences were observed between the wines.  However, preference and descriptive data were not collected, so the effect of FreshArom in this study is still undetermined.

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Co-Fermenting Cabernet Franc with Viognier (2015)

Two lots of Cabernet Franc harvested from the same block were sorted and processed identically. Prior to fermentation Viognier pomace was added to the trial lot (5-7% by volume). The trial wine had lower phenolic and color attributes, likely due to adsorption of phenolic and color compounds on the Viognier pomace.  Tannin was not much lower, but color was greatly lowered.  There were only slight differences in chemistry.  A sensory difference could be distinguished between the control and the trial, with most people preferring the control.

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Hand vs. Machine Harvesting with Viognier (2015)

Machine and hand-harvested Viognier were compared for chemical and sensory differences. The machine-harvested wine had higher pH, higher volatile acidity, and lower titratable acidity.  There was a significant sensory difference between wines, with most people preferring the machine-harvested wine.  This may have been due to some oxidation that the hand-harvested wine experienced.

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