The Effect of Different Cap Management Techniques on Merlot Wine (2016)

This study examines the effect of different cap management techniques on the chemical and sensory qualities of Merlot wine. Merlot grapes were harvested on the same day and split into 3 separate 1-ton T bins with three different treatments: 2 punchdowns per day, 4 punchdowns per day, and 2 pumpovers per day. The timing between 2 punchdowns and pumpovers were approximately 5-8 hours apart, and the timing between 4 punchdowns was approximately 1-2 hours apart. Increasing punchdowns and pumpovers increased the pH (5% and 22% lower proton concentration, respectively) and pumpovers slightly decreased TA. The treatments also increased the volatile acidity and increased the sulfur dioxide binding capacity of the wine. Increasing the number of punchdowns had the greatest impact on color, catechin, and tannin accumulation, although pumpovers slightly increased this as well. Anthocyanins were decreased by the treatments, especially with the 4 punchdown treatment. Overall, these wines were not perceived to be very different from each other. The 2 Punchdown wine seemed to be slightly more preferred than the rest of the treatments, but this was a weak preference. Descriptive analysis from both tastings suggest that the 2 Punchdown wine may have been slightly lower in Astringency, Bitterness, Body, and Herbaceous/Green character. However, if so then this was a very weak trend.

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The Effect of Macro-Oxygenation on Phenolic and Sensory Attributes of Red Wine (2016)

This study examines the effect of different rates of macro-oxygenation on the phenolic and sensory qualities of Cabernet Franc. Grapes were harvested on the same day but kept separate, and all treatments between lots were kept the same except that one T Bin received no macro-oxygenation, one T Bin received a rapid macro-oxygenation to attain 5mg/L added oxygen after punchdowns (<1 hour aeration), and another T Bin received a slow aeration to attain 5mg/L added oxygen after punchdowns (3-4 hours aeration). Oxygen was added after punchdowns. No major chemical or phenolic differences are noticeable between treatments, except that phenolics slightly decreased in aerated wines. Macro-oxygenation tended to lower Overall Aromatic Intensity, with rapid macro-oxygenation tending to lower it the most. There were slight tendencies for macro-oxygenation to increase oxidation qualities and lower Fruit Intensity, and rapid macro-oxygenation tended to have slightly higher Bitterness/Astringency. These tendencies, however, were very weak. In general, people tended to prefer wine made without macro-oxygenation, and least preferred the wine made with rapid macro-oxygenation. Because these trends were very weak, this study should be repeated a few more times before making strong conclusions about macro-oxygenation.

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Whole Cluster Inclusion of Cabernet Franc (2014)

This study examines various stem inclusion and cap management methodology on Cabernet Franc.  One wine was 0% whole cluster inclusion and pressed at dryness, another was 30% whole cluster inclusion and pressed at dryness, and another was 100% whole cluster inclusion and pressed after 3 days.  Whole cluster inclusion slightly increased volatile acidity.  Color intensity decreased with increasing inclusion, as did hue.  In general, people preferred wines with less cluster inclusion.

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Different Maceration Techniques in Cabernet Franc (2015)

Cabernet Franc was fermented in three separate ways.  The control received no cold soak nor extended maceration.  One wine was fermented in the Maceration a Chaud du Marc style, where fermenting juice was racked into another tank where the temperature was kept around 20C (70F), the skin was left in the Tbin and temperature was brought up to 42C (107F) until the juice reached a specific gravity of 1.020 and was blended back with the skin.  The third wine received both a cold soak and extended maceration.  No chemical differences were observed between wines, except that the wine with cold soak and extended maceration had higher pH, lower TA, and lower ethanol.  Maceration a Chaud du Marc slightly increased polymeric pigment and color, and slightly decreased hue.  People tended to prefer the Maceration a Chaud du Marc, in spite of being described of having some typical Brettanomyces aromas.

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Cap Management Comparison with Merlot (2015)

Four Merlot wines were made with varying cap management regimes (all wines were destemmed): 2 punchdowns per day, 4 punchdowns per day, 2 punchdowns per day in addition to being crushed, and 2 pumpovers per day.  There were no real chemical, phenolic, or microbial differences between treatments except that the wine with pumpovers had slightly higher volatile acidity.  People tended to prefer the wine made from crushed grapes with two punchdowns per day.

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