The Impact of Cold Soak vs Extended Maceration in Petit Verdot Wine (2017)

This study examines the impact of cold soaking vs extended maceration on Petit Verdot wine, with maceration time being equal between treatments. The goal was to have on treatment spend more time exposed to an aqueous phase, with the other treatment having more time exposed to an alcoholic phase. Petit Verdot grapes from the same vineyard block were harvested on the same day and destemmed into two separate T Bins. One T Bin underwent a 4 day cold soak prior to inoculation, whereas the other was immediately inoculated without cold soak. Both treatments underwent a 25 day maceration before being pressed off on the same day: thus, the cold soak received less time in contact with must in an alcoholic phase. All other treatments between wines were identical. Wine chemistry and ester profiles were not much different between treatments. The extended maceration treatment had higher levels of color, epicatechin, and tannin, but other phenolic compounds were not much different. The wines were not found to be significantly different via triangle testing. However, there was a strong trend for the cold soak wine to have higher Astringency than the extended maceration wine. There was a slight tendency for this wine to have increased Bitterness and lower Body as well. The total maceration time for these wines was long in both cases, and as such the differences seen here may be greater if smaller overall maceration times are used. In the future, this should be performed, and more microbial analysis should be performed as well.

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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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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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Extended Maceration on Merlot (2015)

Two merlot wines from identical lots of grapes were separated so that one received 3 weeks of extended maceration while the other was immediately pressed after alcoholic fermentation.  There were no chemical differences between these wines, with a slight increase in VA in the extended maceration. The extended maceration wine had more tannin but less anthocyanin, and slightly more browning. Microbial presence was the same between wines.  There were no significant sensory differences or preferences between wines.

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Cold Soak vs. No Cold Soak with Merlot (2014)

Two different Merlot clones (181 and 343) were evaluated for chemical and sensory differences due to cold soaking.  Not much color difference was observed between wines that had undergone cold soak compared to controls.  However, significant sensory differences existed between wines, with most people preferring cold soaked wines.

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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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