Carbonic Maceration in Norton (2017)

This study examines the impact of different winemaking styles on resulting Norton wine. Norton grapes were harvested over two days, and on the first day whole cluster, undamaged grapes were placed into a CO2-purged stainless steel tank with dry 71B yeast on the bottom (this yeast promotes ester formation) while on the second day grapes were destemmed and crushed into multiple T bins. This carbonic maceration tank was gassed with carbon dioxide daily throughout the maceration (approximately 17 days) and held at 65°F. The grapes were then pressed on November 6, and the press fraction was separated, inoculated, and fermented to dryness. The other treatment was punched down twice per day in T Bin throughout fermentation, and the T bins were inoculated with a mix of Lalvin C and Clos yeasts. The T Bins were pressed off on November 3. The carbonic maceration wine has higher alcohol, pH, and VA, with lower TA and lactic acid. The carbonic maceration wine has higher color and phenolic parameters, except for catechin. In sensory analysis, 58% of judges were able to correctly distinguish the wines, suggesting that the wines were significantly different (p<0.01). People who were able to distinguish the wines tended to prefer the carbonic maceration wine. There was a strong trend for the carbonic maceration wine to have higher Body than the traditional fermentation wine. There was a slight tendency for the carbonic maceration wine to have higher Ester Intensity. More studies should be performed on carbonic maceration in Norton and other non-vinifera grape varieties. Additionally, more studies should examine the evolution of aroma and flavor of these wines over time, and how this impacts overall consumer preference.

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Carbonic Maceration in Merlot (2017)

This study examines the difference in aroma, flavor, and mouthfeel produced from fermenting Merlot traditionally versus through carbonic maceration. Merlot grapes were harvested on September 27, and some was split into a macrobin while the rest was added whole cluster to a carbon dioxide-flushed stainless steel tank. The carbonic maceration treatment tank was flushed with carbon dioxide twice per day, and the tank was not opened for 7 days. After 7 days, the carbonic maceration whole clusters were removed, and destemmed into a T bin, where it also received a more traditional fermentation. Musts in T Bins received 2 punchdowns per day. Both T Bins (the traditional and the carbonic maceration one) were pressed off on the same day (October 19). All other treatments between wines were equal. The carbonic maceration wine had lower ethanol, higher TA, and higher succinic acid. Most higher alcohols and esters were higher in the carbonic maceration wine. Color and phenolics were lower in the carbonic maceration wine. There was a significant sensory difference between the carbonic maceration and traditional fermentation wines (p<0.001), with a slight preference for the carbonic maceration wine. These results suggest that carbonic maceration reduces Astringency and increases Ester Intensity and Overall Aromatic Intensity.

 

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Carbonic Maceration vs Traditional Fermentation in Merlot (2016)

This study examined the impact of carbonic maceration on the chemical and sensory qualities of Merlot in comparison to traditional fermentation. Carbonic maceration lowered all phenolic and color attributes in the wine. Most wine chemical parameters stayed the same, except that lactic acid was greatly increased in carbonic maceration. These results suggest that carbonic maceration reduces Body and Astringency compared to traditional fermentation. These results also suggest that the aroma in carbonic maceration changes greatly over a short period of time, as the Fruit Intensity and Ester Intensity of the carbonic maceration tended to more approach that of the traditional fermentation over time. Tasting order had a very large impact on descriptive analysis, so much of these results should be interpreted with care. Because the carbonic maceration wine is intended to be used as a blending component in red winemaking at this winery, in the future blending trials should be performed. Additionally, different carbonic maceration techniques should be employed, such as altering the temperature and time of carbonic maceration, or destemming berries at processing prior to maceration.

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