Understanding Yeast, SO2 and More: Winemakers Take to Trials to Learn More About Common Practices
May 08, 2018
NAPA, CA -- Innovation + Quality 2018 is the fourth annual show dedicated to the concept of using innovation to advance wine quality for luxury and ultra-premium wineries. Wine Business Monthly, presenter of the show, believes that winemaking trials are essential in the pursuit of quality. Now held May 23-24, 2018 at the Silverado Resort & Spa (formerly at Charles Krug), Innovation + Quality, will feature more than 20 winemaker produced trials, with the winemakers themselves presenting and pouring the resultant wines.
This year, a number of winemakers submitted trials related to the additions they make throughout the winemaking process-whether that's in the timing of inoculation, the type of yeast, or whether to add SO2 at all. Join the winemakers from Erath Winery, Van Duzer Vineyards, Hess Collection Winery, Francis Ford Coppola Winery and more, at Innovation + Quality 2018-they'll be on hand to pour wines, discuss the benefits and disadvantages of their tested methods and how each affected their winemaking processes. Tickets for the Winemaker Trials Tastings are just $25, and include lunch, unparalleled networking opportunities and more.
Here's a sneak peek at those trials:
Increased SO2 at Crush to Enhance Color Extraction in Pinot Noir
Winery Name: Chemeketa Cellars
Trial Objective: To determine if increasing SO2 at crush will enhance color extraction in Pinot Noir.
Trial Description: Hypothesis: Increased SO2 concentration during cold soak and maceration can result in increased color extraction. However, this must be balanced with the potential mutation of yeast and ML bacteria. Three tons of Pinot Noir were harvested from a single block on the same day. There was not enough of a single clone, so clones were mixed homogeneously. Fruit was de-stemmed and crushed and divided into four 3/4-ton lots, each in plastic fermentation bins of the same size, shape, etc. Each lot received different amounts of liquid SO2: Lot 1 at 50ppm (control), Lot 2 at 100ppm, Lot 3 at 150ppm and Lot 4 at 200ppm. Each lot was inoculated immediately (BRL97), forgoing cold soak in order to eliminate a compounding variable. Cap management was identical between lots, and specific gravity and fermentation temperatures were monitored daily. Upon completion of alcoholic fermentation, 228L of free run juice from each lot was transferred to identical neutral barrels prior to pressing. Each barrel was inoculated with 1 g/hL ML bacteria (VP41). Malolactic fermentation was monitored as time allowed using [L-malic] spectrophotometric analysis; 55 ppm SO2 (l) was added once MLF was complete.
Lot 1: PN 60 ppm SO2 (control)
Lot 2: PN 100ppm
Lot 3: PN 125ppm
Lot 4: PN 150ppm
Trial Conclusion: Lots had similar alcoholic fermentation kinetics but different malolactic fermentation (MLF) kinetics. The control lot completed MLF (<0.1g/L) 10 days post racking with a linear increase in completion time relative to SO2 concentration at crush thereafter up to 26 days. At 27 days post-addition there was a 49 percent total increase in color intensity (420nm+520nm+620nm) that was linear (R2 0.97) with increased SO2 additions. At 25 days post-addition tannin concentration had increased by 28.5% between the control and the 200ppm lot as well as an increase in total anthocyanin content of 30%. Additionally, a 100% overall increase in the concentration of resveratrol was observed that was linear (R2 0.95) between treatments. These results suggest that increased concentrations of sulfur added at crush could be used to increase anthocyanin and tannin concentration without preventing or significantly delaying malolactic or alcoholic fermentation. However, it is unclear if this color effect is stable and therefore long term. Further investigation into stabilizing co-factors including tannin additions and cooperage is needed.
Comparing the Use of Air and Nitrogen as Flotation Gases
Winery Name: Erath Winery
Trial Objective: The objective of the trial was to compare the sensory effects and analyze the phenolic composition of juice float clarified with air and nitrogen.
Trial Description: A homogenous press fraction of Pinot Gris juice (Umpqua AVA) was processed with a standard pre-floation protocol (pectinase, bentonite, etc.), then split into two separate tanks. One tank was float clarified with air and the other with N2. Two SSDs were collected from each tank, inoculated and fermented until dryness. KMB was added once fermentations were complete and the paired SSDs were racked out to fill a neutral barrel.
Lot 1: 2017 Pinot Gris - float clarified with air
Lot 2: 2017 Pinot Gris - float clarified with nitrogen
Trial Conclusion: Despite starting from an identical and homogeneous press fraction, the two different modes of clarification yielded distinctly difference phenolic profiles. Both resultant wines yielded nearly identical amounts of tannin (10.3 ppm for N2 and 10.7 ppm for air). However, there was a marked difference in GRP, caftaric acid, caffeic acid (~10x more in the N2 float vs. the air float). There was also a significant difference in quercetin glycosides (~7x more in the N2 float vs. the air float). While these are predictable results brought about by oxidation, the resultant wines are distinctly different from a sensory basis. This provides a couple of useful options that might net more degrees of freedom when making stylistic decisions about float clarification and treatment of juice.
Non-Saccharomyces Yeast Comparison in Barrel-fermented Chardonnay
Winery Name: Sonoma-Cutrer Vineyards
Trial Objective: The objective is to see if non-Saccharomyces yeast add more complexity to barrel-fermented Chardonnay.
Lot 1: Alpha + VL2
Lot 2: Concerto + VL2
Lot 3: VL2 Only
Trial Conclusion: TBD. We need multiple years of non-Saccharomyces yeast trials to determine sensory effects.
Co-inoculation of Malolactic Bacteria vs. Sequential Inoculation in Carneros Pinot Noir and Dry Creek Valley Cabernet Sauvignon
Winery Name: Francis Ford Coppola Winery
Trial Objective: To enhance fruitiness and mouthfeel, producing true appellation expression, controlling spontaneous ML fermentation, and getting our wines ready for market sooner and stabilizing color and tannin.
Trial Description: We are looking to achieve a more fruit-forward wine style as well as enhance quality and decrease overall cost. Using a co-inoculation method, we were able to achieve an enhanced fruit expression and a wine ready for maturation and market sooner than traditional sequential ML inoculation. Trial Steps: Inoculated experiment tank 24 hours after primary fermentation had started. With 1° Brix drop, inoculated with malolactic bacteria. Control tanks were inoculated with ML after primary fermentation completion. Normal fermentation analysis protocols continued through the primary fermentation. Nutrient additions were made at Day 1 and at 12° to 18° Brix. ML and VA were tracked daily if possible.
Lot 1: Carneros Pinot Noir - Control
Lot 2: Carneros Pinot Noir - Co-inoculated
Lot 3: Dry Creek Valley Cabernet Sauvignon - Control
Lot 4: Dry Creek Valley Cabernet Sauvignon - Co-inoculated
Trial Conclusion: Co-inoculation with malolactic bacteria is a useful tool to enhance fruitiness, increase mouthfeel, and achieve stability securely and more efficiently. We were able to re-use press lees to inoculate and complete other wines. We were able to SO2 sooner and have less VA pick up, requiring less SO2 in the lifetime of this wine. By controlling MLF fermentation, we are protecting against any off flavors from lactobacillus and pediococcus, as well as enhancing and supporting specialty yeasts.
Effect of Direct Inoculation vs. Normal Rehydration of GVS107 Yeast on Chardonnay
Winery Name: Hess Collection Winery
Trial Objective: The objective of the trial is to compare the fermentation and the resulting wine of Chardonnay made from an easy-to-use Fermentis yeast used with a normal rehydration protocol versus a direct inoculation in the tank.
Trial Description: The Chardonnay juice was homogenized between two similar tanks of 25,000 gallons in order to reach identical initial conditions. The first tank was inoculated following a normal rehydration at a rate of 20g/hl. Yeast in 10 times its weight of tap water at 30° to 35°C in a wide vessel was poured in covering all the water surface area by creating a thin layer of yeast and rested for 20 minutes. Volume of the yeast suspension was slowly doubled by adding must from the tank while stirring in order to decrease the temperature of the yeast starter and to start the activation of the yeast, and then rested for another 10 minutes. Yeast starter was homogenized and incorporated to the must. The second tank was directly inoculated in the tank, at the same time and also at a rate of 20g/hl. All additions and operations were identical for the two tanks. YAN was adjusted to 250ppm on both tanks. Data collection for each tank included initial and final chemistry as well as daily Brix/temperature.
Lot 1: Chardonnay - Normal rehydration
Lot 2: Chardonnay - Direct inoculation
Trial Conclusion: The fermentation data will be provided to prove that there is no significant difference between the fermentation profile of the two tanks (lag phase, time to dryness, general fermentation curve, temperature curve).
Using No-SO2 Wine Production Methods on Pinot Noir
Winery Name: Van Duzer Vineyards
Trial Objective: The objective of the trial is to produce wines without, or with a low amount of, SO2, using allergen-free alternatives for the entire winemaking process.
Trial Description: The trial has been done on Pinot Noir grapes, harvested at the same time, from the same block using Enartis Ferm MB15 yeast. The control has been processed with the standard addition of SO2 (40 ppm). The full no-SO2 protocol has been processed using alternatives such as Enartis Stab Micro M (pre-activated chitosan) for antimicrobial, Enartis Tan Fermcolor (sacrificial tannins) as anti-oxidant, Enartis pro blanco (yeast derivatives rich in sulfur peptides and Enartis Tan SLI as anti-oxidant during barrel ageing. Weekly assessment and monitoring of spoilage microbes was conducted.
Lot 1: Pinot Noir - Control
Lot 2: Pinot Noir - No SO2 Enartis protocol
Trial Conclusion: Chitosan appears to be an effective way to control microbial growth from harvest to bottling. By reducing, or in this case removing, SO2 usage, the final wine appears to have darker color intensity and showcases more aromatics. It is noticeable to mention that Chitosan do not protect against oxidation and that a strategy including the usage of tannins and polysaccharides needs to be implemented for successful results.
For a full list of trials being presented and poured at the conference, visit www.winebusinessiq.com.
All Winemaker Trials Tastings will be held on May 24, 2018. Tickets are $25. Access to trials pourings is included with IQ Session Pass Tickets. Click here for more information and to register.
About Innovation + Quality
Innovation + Quality (IQ) 2018 is the fourth annual forum for ultra-premium wineries focused on cutting-edge innovations that advance wine quality. This two-day event takes place May 23 & 24, 2018 at Silverado Resort & Spa in Napa Valley (formerly at Charles Krug Winery).
This event is produced by Wine Business Monthly, the leading print publication for the wine industry, in partnership with Napa Valley Vintners and the Napa County Farm Bureau.