The Impact of Adding Chardonnay Lees to Aging Red Wine (2017)

This study examines the impact of adding chardonnay lees to aging Cabernet Franc wine on mouthfeel and aroma. Cabernet Franc wine was cleanly racked into 3 separate, identical barrels on December 29, 2017 so that very little lees were transferred. Then: 1) one barrel received no addition of Chardonnay lees, 2) one received 1 liter of Chardonnay lees, approximately 1.02E6 cells/mL (Low NTU), and 3) one received 3 liters of Chardonnay lees, approximately 3.06E6 cells/mL. Lees were light lees, harvested from Chardonnay wines fermented with D254. The yeast in the lees were budding under microscope, and so 90ppm of sulfur dioxide was added to the lees before adding to barrel. The wines were stirred once every two weeks until taken for sampling in late March, 2018. No major wine chemistry differences were apparent between treatments. Sulfides were all similar between wines, with some differences in Dimethyl Sulfide. Microbial cell counts were generally higher in wine with lees additions. Color intensity was slightly lower in wine with lees added. Phenolic profiles were very similar, with perhaps a slight decrease in tannin with lees addition. Overall, low lees addition had a slight tendency to increase Fruit Intensity. Lees addition in general seemed to slightly lower Astringency. However, many of these differences were weak, and differed between tastings. The lees addition wines were generally more preferred over the control wine. This suggests that lees addition to red wines can be of benefit to red wine quality. More research with more rigorous sensory analysis is needed to further clarify what aspects of wine sensory characteristics are impacted by lees addition.

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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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The Impact of Racking and Returning on Wine Quality (2017)

This study examines the impact of racking and returning during aging on red wine quality. Petit Verdot wine was split into two identical barrels. Once malolactic conversion was completed, one barrel was racked into tank, the barrel was pressure washed and ozonated, and then the wine was returned to the barrel and topped. The other barrel had no treatment. All other treatments between wines were identical. No major chemical differences were apparent between treatments. VA was slightly lower in the racked wine. Some sulfide parameters were lower in the racked wine, although whether these differences would impact flavor is hard to say. For the triangle test, of 20 people who answered, 7 people chose the correct wine (35%), suggesting that these wines were not significantly different. In general, of those who correctly identified the wines, 2 had no preference, 2 preferred the control, and 3 preferred the rack and returned wine. For the descriptive analysis, there were no trends for the descriptors used in this study. Judges commented that these wines were very extracted, which may have masked differences between wines. In the future, this study should be repeated on less intense grape varieties. Furthermore, the wine should be allowed to age more in future studies.

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The Impact of Lees Stirring on Red Wine Quality (2017)

This study examines impact of stirring the lees of barrel aging red wines. Cabernet Franc wine was settled overnight in tank after pressing and then racked into two identical neutral barrels. Barrel stirring occurred once malolactic fermentation completed and continued once every two weeks until wine was sampled in late April. No major differences were found in wine chemistry. Some lactic acid bacteria counts were higher, and Brettanomyces and Saccharomyces was higher in the stirred wines as well. No differences were apparent in phenolics, except for an increase in tannin in the stirred wine. For the triangle test, of 21 people who answered, 7 people chose the correct wine (33%), suggesting that the wines were not significantly different. In general, of those who correctly distinguished the wines, 3 had no preference, 2 preferred the stirred wine, and 1 preferred the no stirring wine. For the descriptive analysis, there were no strong trends for the descriptors used in this study. There was a very slight trend for the stirred wine to have lower Astringency. In the future, more studies should be performed with red wine lees stirring, perhaps with differing levels of lees in the wines as well.

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The Effect of Different Sources of Lees and Lees Products on Aging Cabernet Franc Wine (2016)

This study examines the impact of adding different sources of lees to aging Cabernet Franc wine. Cabernet Franc wine was split into 5 barrels with the following treatments: 1) no lees addition, 2) 2 pints of Chardonnay lees added, 3) 2 pints of Viognier Lees added, 4) Laffort Autolees added, and 5) AEB Batonnage Elevage added. The wines were stirred once every two weeks until taken for sampling (in February). Wine chemistry did not differ between treatments. The sulfide profile did not differ at the limit of detection of the laboratory analyses. All treatments slightly lowered color intensity and increased hue, except for the AEB Batonnage treatment, which increased color intensity and decreased hue. In the first tasting, the Control and the Laffort Autolees treatment strongly increased Fruit Intensity, but this was not replicated at the second tasting. There were weaker tendencies between tastings, however. Lees which originated from wine (Viognier and Chardonnay Lees) appeared to have a consistent impact on the aroma of the wines, whereas lees which originated from products had less impact on wine aroma. An exception would be the AEB Battonage Plus treatment, which appeared to increase Herbaceous/Green qualities. The AEB lees tended to have the largest impact on Astringency. No major preference trends could be seen. These results were very mixed, likely due in part to the complexity of the project. This project produced interesting results, and more work on the impact of lees management in red wines should be done before drawing hard conclusions about these different lees sources. Stylistic possibilities of adding aromatic white wine lees to red wine should also be considered in future studies.

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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. Chardonnay juice was fermented in barrels, and afterwards 3 different stirring regimes were imposed: unstirred, stirred, and stirred with Extralyse (Laffort). Stirring occurred once per week for 8 weeks. The finished wines showed decreasing levels of residual sugar with stirring and with enzyme addition. Some malolactic fermentation could be observed in the stirred wine with Extralyse as well. Wine tended to become more cold stable over time, but the unstirred wine showed the highest level of cold stability but also the highest level of bentonite addition necessary to become heat stable. These results suggest that stirring may enhance Sweetness, Depth of Flavor, Yeast Character, and Body, although many of these effects were weak. The effect of Extralyse in combination with stirring was not too different than from stirring itself. 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, particularly with respect to Extralyse.

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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 wine. Chardonnay juice was fermented partially in tank before being aeratively racked with lees inclusion to finish fermentation in barrels, and afterwards 2 different stirring regimes were imposed: unstirred and stirred with Extralyse (Laffort). Stirring occurred once per week for 8 weeks. No major chemical differences could be observed between treatments, and both wines underwent partial malolactic conversion. Wines tended to become more cold stable and heat stable over time, with stirring and Extralyse potentially making the wine slightly more heat stable than not stirring. Of 10 judges, 9 were able to correctly distinguish the wines from each other, showing that these wines were significantly different (p<0.001); however, this may have been because the stirred wine was cloudy. 8 out of 8 people tended to prefer the wine with Extralyse; however, the unstirred wine may have had some oxidized characteristics. Wine produced with Extralyse and Stirring had a strong tendency to be higher in Sweetness and Body, and tended to have slightly higher Yeast Character and Depth of Flavor. 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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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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