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World's Leading Smoke Taint Researchers Converge for Innovation + Quality 2018

From educational sessions, to winemaker trials and a fundraiser to enable researchers to better understand the phenomenon, IQ 2018 will dive deep into the effects of smoke taint on premium wines.
May 10, 2018

NAPA, CA--The world's foremost smoke taint researchers are converging at Innovation + Quality, held May 23-24, 2018 at the Silverado Resort and Spa, to provide insight into the leading explorations and investigations on a type of natural disaster that has affected winemakers and regions across the globe this year. What do we know (or don't know) about how smoke taint affects wine? Are there removal methods? Join researchers from Australia, Italy, Canada, California and Washington state as they discuss their latest findings, best practices and more.

Speakers:
Moderator: Cyril Penn, Wine Business Monthly
Anita Oberholster, Ph.D., University of California, Davis
Kerry L. Wilkinson, Ph.D., University of Adelaide
Tom Collins, Ph.D., Washington State University
Wesley Zandberg, Ph.D., University of British Columbia
Fabio Mencarelli, University of Tuscia

Following this session, join the researchers, winemakers and more for IQ Connect, a reception and fundraiser created by the team at Wine Business Monthly. Proceeds from ticket sales benefit enterprising smoke taint researchers looking for new discoveries on how it affects a final wine, removal methods and more. Admittance to IQ CONNECT is included with an IQ All Access pass, or can be purchased independently for $150. IQ Connect pass holders also gain admittance to the Winemaker Trials Tasting the next day.

Several of those researchers and the winemakers from Carneros Vintners and A to Z Wineworks will present the results of their smoke taint trials. Here’s a sneak peek:

Assessing Smoke Taint Risk

Winery Name: Washington State University

Trial Objective: The objective of the trial is to generate smoke affected wines by exposing field-grown grapevines to simulated wildfire smoke

Trial Description: Merlot and Cabernet Sauvignon grapevines at the WSU Prosser Irrigated Agriculture Research and Extension Center (IAREC) were exposed to simulated wildfire smoke during the 2017 growing season. For each variety, four rows of 30 vines were covered by temporary hoop-house structures, two rows each for the control and for the smoked treatment, for a total of 60 vines for each treatment. The vines in the smoke treatment were exposed to simulated wildfire smoke generated by burning either a mixture of plants typically found in rangelands in eastern Washington for the Merlot vines or a mixture of conifer bark mulch for the Cabernet Sauvignon vines. Smoke intensity was monitored using TSI Dusttrak aerosol particle monitors (TSI, Inc., Shoreview, MN) while smoking duration was 38 hours for the Cabernet Sauvignon vines and 48 hours for the Merlot vines. Smoke was delivered from the smoke generator to the fruiting zone in the vineyard canopy using 4-inch flexible drain lines.

Wines were made from the control and smoke affected fruit at the Chateau Ste Michelle/WSU Wine Science Center in Richland, WA, using standard WSU red wine protocols. Samples were collected daily throughout the fermentation and stored at -80C for subsequent analysis of smoke taint related volatiles using GC/MS and non-volatiles (glycosides) using UHPLC/QTOF-MS. Additional samples have been collected at weekly intervals since the end of fermentation to assess changes in composition over time.

Lot 1: Merlot, control vines
Lot 2: Merlot, smoked vines
Lot 3: Cabernet Sauvignon, control vines
Lot 4: Cabernet Sauvignon, smoked vines

Trial Conclusion: The Merlot and Cabernet Sauvignon vineyard blocks used for this trial were exposed to real wildfire smoke during the 2017 growing season, in addition to the smoke applied as treatment during this trial. The intensity and duration of these "wild" wildfire episodes were monitored using the TSI Dusttrak monitors, which recorded time weight averages for the two smoke episodes that were much lower than the treatments applied during the trial. In spite of this exposure there are differences in the sensory perception of the control and smoked treatments for both varieties. Analysis of the volatile and non-volatile composition is ongoing.

Flash Detente as a Mitigation Technique for Smoke-exposed Grapes

Winery Name:
Carneros Vintners

Trial Objective: The objective was to assess the use of Flash Detente as a mitigation technique for smoke-exposed grapes.

Trial Description: Due to the recent firestorms in the North Coast, much attention has been focused on the issue of smoke taint. This trial attempted to assess the effects of flash on the chemistry and sensory character of smoke exposed grapes from Napa and Sonoma. Grapes harvested after Oct. 8 with known exposure to smoke were received by Carneros Vintners, with the client's intention of using flash to reduce the smoke's impact. A portion of the grapes were set aside for 'traditional fermentation' in small lots and the balance was flashed. The resulting wines were analyzed and several pairs will be available for tasting.

Lot 1:
Cabernet Sauvignon (Napa)- Control
Lot 2: Cabernet Sauvignon (Napa)- Flash
Lot 3: Merlot (Sonoma)- Control
Lot 4: Merlot (Sonoma) - Flash

Trial Conclusion: In these wines, Flash decreased the amount of free guiacols by an average of 53 percent. Total guiacols showed more moderate reductions (12 percent). However, total guiacols were not increased in the flash wines, as might have been feared. Benchtop sensory shows the flash samples have an improved nose, with the most offensive aromas being reduced or even eliminated. Smoke flavors, particularly the retro-nasal "ashtray" finish, are slightly reduced by flash treatment but still present. In that regard, the analysis and tasting tell a consistent story. While Flash might be a step in the right direction, the problem of completely removing smoke taint is likely to require addressing the bound forms. Given the intermittent nature of smoke taint, a chance to taste these trials seems worthwhile.

The Effect of Maceration Timing on Smoke Taint Extraction

Winery Name:
A to Z Wineworks

Trial Objective:
The objective of the trial is to determine whether pressing a ferment before dryness or including a cold soak will affect the levels of smoke taint compounds in the finished wine.

Trial Description:
Three 1.5 ton fermenters were filled with machine-harvested Pinot Noir from the same vineyard block. A blend sample of the three tanks was sent in for smoke taint analysis 12 hours after filling, or approximately 20 hours of total soaking time. This result showed a guaiacol concentration of 8.8 µg/L. The first tank had no cold soak, and was fermented to dryness, for a total of 8 days on skins. This tank had a final guaiacol concentration of 14.3 µg/L. The second tank had a 3-day cold soak and was then fermented to dryness, for a total of 12 days on skins. This tank had a final guaiacol concentration of 13.0 µg/L. The third tank had a 3-day cold soak and was then pressed at 5° Brix, for a total of 8 days on skins. This tank had a final guaiacol concentration of 13.3 µg/L. All three tanks had a final 4-methylguaiacol concentration of 2.0 µg/L.

Lot 1: Pinot Noir with no cold soak, fermented to dryness - 8 days on skins
Lot 2: Pinot Noir with a 3-day cold soak, fermented to dryness - 12 days on skins
Lot 3: Pinot Noir a 3-day cold soak, pressed at 5° Brix - 8 days on skins

Trial Conclusion: Despite having 4 days more on skins than the other two tanks, the second tank did not show any additional extraction of guaiacol or 4-methylguaiacol, but actually contained slightly less guaiacol. It also did not seem to make much difference. This suggests that all the smoke taint compounds were extracted in the first 8 days on skins, so macerating for an additional 4 days did not increase levels of smoke taint. In addition, we found that by extracting more tannin from the skins in those additional days of maceration, the smoke taint compounds might be less perceptible in tastings compared to the lots with less time on skins.

Using Ozone (Purovino) to Remove Smoke Taint

Winery Name: Deerfield Ranch/University of Tuscia

Trial Objective: To eliminate/reduce the impact of grapes tainted by the Oct. 2017 fires and to produce a finished product that exhibits not only no smoke taste but also exhibits the characteristics of the Purovino process to include enhanced extraction and increased antioxidants.

Lot 1: Cabernet Sauvignon - Untreated (Control)
Lot 2: Cabernet Sauvignon - Treated with Purovino process in same oak barrel as control wine
Lot 3: Cabernet Sauvignon - Treated with Purovino process in different oak barrel as control

Trial Conclusion: There was no detectable evidence of smoke taint in the Purovino treated lots in either barrel type vs the control and the level of phenolics and antioxidants was increased.

How Fermentation Temperature and Oak Regimen Affect Smoke-tainted Cabernet

Winery Name: UC Davis Research and Teaching Winery

Trial Description:
Wines were produced from 2017 Cabernet Sauvignon smoke impacted grapes at the UC Davis Research and Teaching winery. The impact of both fermentation temperature and oak additives on smoke taint characteristics were investigated as these are among the general recommendations made to wineries regarding potential mitigation of smoke taint development in wines.

Trial 1:
Comparing wines fermented at 25° C and 15° C as the Australians recommend cooler fermentation; reds in their trials are fermented at 15° C (2 wines).

Trial 2: Fermenting smoke-impacted grapes with two different types of oak chips compared to a control (3 wines).


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.


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