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.
This study examines the impact of different yeast strains on green character in Cabernet Franc. Cabernet Franc grapes were harvested and processed on the same day into 3 separate T Bins. Each T Bin received 25ppm sulfur dioxide and were then inoculated with either CSM (ScottLabs), D254 (ScottLabs), or D20 (Enartis). D20 yeast may reduce green character through higher fermentation temperatures blowing off pyrazine (Enartis 2018), therefore this T bin was fermented in the sun. CSM was chosen because it is also marketed as being able to reduce green character (Scott Laboratories 2018), but since it did not specify a higher fermentation temperature, this treatment was not fermented in the sun. Each T Bin was punched down twice per day and pressed on the same day for 9 days of maceration. All other treatments between wines were identical. All yeast strains had similar fermentation kinetics, with D20 perhaps being slightly warmer. Wine chemistry was similar between treatments, except that IBMP was slightly lower in the D20 yeast treatment. There were no strong trends for the descriptors used in this study. There was a slight trend for the CSM wine to have higher Fruit Intensity, and for the CSM and D20 wines to have higher Astringency. There was a slight preference for the D254 wine.
This study examines the impact of Rubino Extra (2B), BM45 (ScottLabs), and Alchemy III (Anchor) on the phenolic and aroma characteristics of Cabernet Franc wines. The goal was to see if the Rubino Extra yeast could enhance anthocyanin and aroma extraction from the grapes, relative to other yeast strains. Grapes were harvested on the same day and processed into 3 separate T Bins. Each of the three T Bins were inoculated with one of the three yeasts. All other treatments between wines were identical. The BM45 trial fermented slowest, and Rubino Extra trial fermented fastest. Lactic acid was higher in the wine produced with BM45. Color intensity varied among yeasts. Anthocyanins were higher in the Alchemy 3 trial, and lower in the Rubino Extra trial. Overall, not many trends were seen between these wines. The Rubino Extra yeast tended to produce wines with slightly lower Overall Aromatic Intensity and Fruit Intensity. The Alchemy 3 and BM45 yeasts were fairly similar, except that BM45 was perhaps more in-between the Rubino Extra and the Alchemy 3 yeast. The Alchemy 3 yeast appeared to produce a distinctive floral or fruity quality. Preference trends reversed between tastings, and as such it is unclear which yeast strain was the most preferred.
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.
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.
This study examines the effect of different low H2S-producing yeast strains on the sensory attributes of Cabernet Franc and Cabernet Sauvignon Rosé. The grapes were harvested on the same day, pressed together, and after settling was racked into four different 484L puncheons (2006 Hungarian oak from the same cooper). The barrels were inoculated with the following yeasts: Rhône 4600 (ScottLabs), Allegro (Phyterra), Sensy (ScottLabs), and Fermol Elegance (AEB). Rhône 4600 is not marketed as a low H2S-producing yeast strain and was intended to act as a soft control. The strains showed similar fermentation kinetics except for Rhône 4600, which was markedly slower. Additionally, the wine produced by Rhône 4600 had a higher alcohol content and higher total SO2, possibly from yeast production. The sulfide contents of the wines, however, were essentially indistinguishable. No strong trends were found with the descriptors used for this study. Rhône 4600 tended to show higher Fruit Intensity and Overall Aromatic Intensity. Many of these wines were perceived as slightly reduced. In general, people tended to prefer wines produced with Rhône 4600 and Allegro yeasts.
The yeast strains Enartis ES488 and Lallemand GRE were used in order to lower green character in Cabernet Franc. The titratable acidity between wines was fairly different, but sensory analysis did not show significant differences between the two wines. This study does not conclusively show whether these yeasts can diminish green character.