Levulia Alcomeno Yeast Trial (AEB) (2017)

This study examines the impact of Levulia Alcomeno yeast (AEB) on Cabernet Franc wine quality. Levulia Alcomeno is a non-Saccharomyces yeast strain (K. thermotolerans) which can promote acid formation and decrease acidity during early stages of fermentation. Cabernet Franc grapes were divided into two T Bins, one of which received Levulia Alcomeno and the other did not. Both T Bins underwent a 7 day cold soak. Afterwards, the control was inoculated with FX-10, and both T Bins were fermented identically. Roughly halfway through fermentation, the Levulia treatment received FX-10 as well in order to ensure complete fermentation. All other treatments between wines were identical. Chemistry was not altered during cold soak. Fermentation kinetics were very similar between treatments. Levulia Alcomeno wine saw increased TA, lactic acid, and volatile acidity. However, this wine also had higher pH. The Levulia Alcomeno wine had higher levels of ethyl acetate and isobutanol, and slightly lower levels of amyl alcohol and isoamyl alcohol. Color was not very different between treatments. The wines were not determined to be significantly different via triangle testing. Of those who answered the triangle test correctly, they preferred the control wine, and there may have been a nondescript off flavor in the Levulia wine. For the descriptive analysis, there were no strong trends for the descriptors used in this study. The descriptive data suggests that there may have been some glass-to-glass variation, possibly due to biases from tasting order. Drawing sensory results is thus difficult. Levulia Alcomeno is recommended to be used in conjunction with Fermol yeasts, which may have impacted results. In the future, more studies should be performed on this yeast in conjunction with AEB Fermol yeasts.

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Yeast Strain Selection to Produce Sulfur Dioxide-Free Merlot Wine (2017)

This study examines the efficacy of non-Saccharomyces yeast selection to produce wines without the use of sulfur dioxide. Merlot grapes were harvested on September 28 and stored overnight at 45°F. The next day fruit was destemmed, sorted, and crushed into two separate bins (0.5 tons per treatment). One bin received 6g/hL sulfur dioxide (control), and the other received 5g/hL Primaflora VR Bio (AEB) as a sulfur dioxide replacement (no sulfur dioxide treatment). Both bins received a two day cold soak (one punchdown per day, with dry ice additions), and then the control bin received 15g/hL FX10, and the treatment received 15g/hL FX10. At this point the bins were moved out of the cold room in order to warm up. Punchdowns were twice per day until fermentation became vigorous (October 6), which then received 3 punchdowns per day. Fermentation lasted for 8 days, after which the wine was drained off the skins and put into stainless steel tanks for aging (only free run was used). On November 30, wines were filtered with K250/EK filters and sterile filtered (0.45 micron) and bottled on December 7. At bottling, the control received 1g/hL sulfur dioxide. The wine without sulfur dioxide had slightly less alcohol and lactic acid, and slightly increased volatile acidity. It also had less color and had a slightly longer lag phase in fermentation. The no sulfur dioxide wine seemed to have more yeasts throughout its life except for Hanseniaspora, relative to the control. Both fermentations had similar bacterial counts. Overall, judges were more or less able to correctly distinguish the wines made with and without sulfur dioxide, although in one tasting this was statistically significant and at the other it was not. Judges tended to prefer the wine made without sulfur dioxide. The no sulfur wine may have had higher Fruit Intensity, higher Overall Aromatic Intensity, and higher perceived Acidity relative to the wine made with sulfur dioxide.

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The Effect of Zymaflore Alpha Yeast (Laffort) during Cold Soak on Cabernet Franc Wine (2016)

This study examines the impact of adding Zymaflore Alpha (T. delbrueckii) (Laffort) yeast prior to a cold soak on the chemical and sensory characteristics of Cabernet Franc wine. Cabernet Franc from the same block was harvested on the same day and processed into two separate T Bins. All additions were identical, except that one T Bin received Zymaflore Alpha yeast and the other received no yeast. Both bins then underwent a 6 day cold soak at 50°F. After cold soak, both bins were inoculated with FX 10 yeast. All other treatments were identical. Wine was pressed around 3 weeks after processing. The Zymaflore treatment lowered titratable acidity and slightly lowered ethanol, but otherwise no major chemistry differences were apparent between wines. The Zymaflore treatment had increased acetaldehyde and propanol, but most other higher alcohols and fusel oils were lowered by the treatment. The Zymaflore treatment also slightly lowered color intensity. Triangle testing showed that, of 7 people who answered, 4 people chose the correct wine (57%), suggesting that the wines were not significantly different. However, the wines were almost significantly different. 3 out of 4 judges who answered correctly preferred the Zymaflore treatment to the control, and the other judge had no preference. The wine with Zymaflore was described as being slightly smoother, less harsh, or more balanced in terms of acidity. No major trends were discovered for the descriptors used in this study. There was a slight tendency for the Zymaflore wine to have lower Astringency and Overall Aromatic Intensity. The use of non-Saccharomyces yeast strains merits further work.

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Levulia Alcomeno (AEB) Yeast Trial on Cabernet Franc (2016)

This study examines the impact of Levulia Alcomeno (K. thermotolerans) yeast inoculation followed by inoculation with FX-10 after 4 days versus inoculating with FX-10 alone on Cabernet Franc wine. K. thermotolerans is a yeast species which often produces wine of higher acidity and lower ethanol. Although the Levulia Alcomeno fermentation had a longer lag phase, they both finished fermentation around the same time. Wine fermented with Levulia Alcomeno showed slightly increased TA, lactic acid, and decreased pH and ethanol, which is consistent with K. thermotolerans fermentation profiles. The decrease in pH corresponds to a 23% increase in proton concentration. Additionally, this wine showed less acetaldehyde and more isoamyl alcohol. These results suggest that Levulia Alcomeno, while potentially affecting the chemical makeup of wine, did not have a strong impact on the sensory qualities of wine. It may have slightly increased Fruit Intensity and decreased Astringency, but if so this was a weak trend. This yeast shows promise, however, and more studies are warranted to determine whether this yeast can reproducibly produce these effects, and whether these effects are enhanced based on different starting fruit chemistry. At this point, no firm conclusions can be drawn.

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