Fermenting Merlot in T Bins vs Tanks (2017)

Fermenting in T bins is a common practice in Virginia but may impact wine quality in ways different from fermenting in stainless steel tanks. Thus, investigating the use of these vessels is important for the Virginia wine industry. This study compares fermenting Merlot grapes in T Bins or in Stainless Steel Tanks. Merlot grapes were harvested from the same block and chilled overnight in a refrigerated truck. Grapes were then destemmed but not crushed into a 0.75 ton T Bin as well as a 3 ton stainless steel tank. Fermentations were punched down twice daily throughout fermentation and pressed off after 19 total days. Wine was settled in tank after pressing for 5 days before barreling. All other treatments between wines were identical. The area:height ratio of the tank and the T Bin are approximately 1.340m2/m and 1.355m2/m, respectively. Thus, differences seen are likely not due to dimensions. The T Bin fermentation reached higher fermentation temperatures and exhibited a slightly faster fermentation. The T Bin fermentation resulted in decreased alcohol and increased TA. The T bin had higher tartaric acid, lactic acid, and succinic acid. Color intensity and many phenolic parameters were decreased in the T Bin wine as well. For the triangle test, of 27 people who answered, 15 people chose the correct wine (56%), suggesting a statistically significant difference between wines (p<0.01). These wines were voted to have an average degree difference of 4.6 (out of 10), suggesting that the wines were moderately different. In general, people who answered correctly preferred the tank fermentation the most. For the descriptive analysis, there were no strong trends for the descriptors used in this study. There was a slight tendency for the T Bin wine to have higher Fruit Intensity and Herbaceous/Green character, and lower Bitterness, Astringency, and perhaps lower Body. Judges remarked that there may have been a strange aroma in the T Bin wine, ranging from sulfuric to volatile acidity to ethyl acetate. This may have impacted the perception of Fruit Intensity in this wine. From the chemistry, it is not clear what may be causing this aroma. These differences are hypothesized to be caused by differences in temperature and oxygen exposure between treatments, although not enough data is available to confirm or deny this. In the future this study should be repeated multiple times to gain more information and should be analyzed in more detail.

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The Impact of Barrel Stirring on Cabernet Franc (2017)

This study examines the effect of barrel stirring during aging on Cabernet Franc. Cabernet Franc wine (free run and pressings) was settled for 48 hours and then racked into two identical neutral barrels. After malolactic fermentation, barrels were sulfited and one barrel was left unstirred whereas the other barrel was stirred once per week for three months. All other treatments between wines were equal. Wine chemistry was not different between treatments. The barrel stirred wine had slightly higher levels of acetic acid bacteria, some lactobacillus species, and perhaps Saccharomyces cerevisiae. O. oeni was higher in the barrel stirred treatment as well. Tannin may have been slightly lowered by barrel stirring, and catechin may have slightly increased. Overall, the wines were not found to be significantly different. Of the people who correctly distinguished the wines, there may have been a slight preference for the unstirred wine (although the tendency to have no preference was also strong). This study should be repeated again in the future, perhaps with differing levels of lees in each treatment as well and with the turbidity measured.

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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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Chardonnay Lees Management (2016)

This study examined the impact of lees stirring during Chardonnay aging on the chemical and sensory qualities of the wine. It is a companion study to Blenheim’s Chardonnay Lees Management with Extralyse (ARC) study (2016). Chardonnay juice was fermented in sets of barrels, after which one was left unstirred while the other was stirred during aging. Stirring occurred once per week for 8 weeks. No major chemical differences could be observed between the finished wines. Wine tended to become more cold stable over time, but the unstirred wine required the lowest bentonite addition to become heat stable. Additionally, increasing bentonite additions to become heat stable were necessary after aging. This study suggests that stirring has a noticeable effect on finished wine, but this effect is not necessarily preferred or disliked (perhaps a slight preference towards stirred wines). The descriptors used generally did not help elucidate which qualities in wine were affected by stirring. Some trends seemed to result from stirring, such as a potential increase in body, yeast character, and depth of flavor. Bitterness may have been slightly decreased as well. However, no firm conclusions can be drawn in these regards. The stirring regime for this study was relatively short (8 weeks). In the future, more realistic stirring regimes should be implemented to see whether differences tend to increase over time.

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Chardonnay Lees Management with Extralyse (ARC) (2016)

This study examined the impact of lees stirring and batonnage enzyme addition during Chardonnay aging on the chemical and sensory qualities of the wine. It is a companion study to Blenheim’s Chardonnay Lees Management (2016), which compared the effects of not stirring Chardonnay to stirring Chardonnay. Chardonnay juice was fermented in barrels, and afterwards two different treatments were imposed: stirred, and stirred with Extralyse (Laffort). Stirring occurred once per week for 8 weeks. No major chemical differences could be observed between the finished wines. Wine tended to become more cold stable over time. Additionally, increased bentonite additions to become heat stable were necessary after aging. In general, people often could not distinguish between stirring and stirring with Extralyse. When people could distinguish, there appeared to be a slight preference for wine made with Extralyse. The descriptors used generally did not help elucidate which qualities in wine were affected by stirring. There may be a small tendency for Extralyse to enhance Fruit Intensity and Depth of Flavor, but these tendencies were weak. However, the stirring regime for this study was relatively short (8 weeks). In the future, more realistic stirring regimes should be implemented to see whether differences tend to increase over time.

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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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Screw Cap Closure Comparison (2015)

The effect of three different Amcor Stelvin screw caps with different oxygen transfer rates on bottled Chardonnay wine were compared in this study.  The chemical parameters measured in this study did not show much differences; however in general tasters preferred the screw caps with lower oxygen transfer rates.  The length of time from bottling to tasting and analysis, however, may have been too short to truly distinguish differences.

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Sulfur Dioxide Resistant Strains of EC 1118 (2014)

EC 1118 produces high concentrations of sulfur dioxide during fermentation.  Some sulfur dioxide-resistant strains of EC 1118 have been developed in response to this tendency.  This study examines the difference in wine chemistry, fermentation kinetics, and sensory characteristics of wine produced using traditional EC 1118 and the sulfur dioxide-resistant strain of EC 1118.  The resistant strain produced less volatile acidity, but resulted in a longer fermentation.  No significant sensory differences were found between wines.

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Anchor and ScottLabs Yeast Comparison in Merlot (2014)

ScottLabs EC 1118 PDM, ScottLabs CRVP, Anchor NT50, and Anchor NT202 yeast strains were compared for their effect on pH, ethanol and volatile acidity production in 2014 Merlot.  Fermentation kinetics were also compared.  CRVP exhibited the fastest fermentation kinetics but produced the highest volatile acidity. EC 1118 PDM produced the highest ethanol and lowest volatile acidity.

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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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