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Enology – Enological Method Development Session
June 18, 2026 | 4:10 pm – 4:50 pm | Location: Grand Ballroom 100C
Research Reports
Moderator:
To be announced.
Speakers:
| 4:10 pm – 4:30 pm | Rapid Measurement of “Green” and “Moldy” Odorants in Grapes using Direct Analysis in Real Time Mass Spectrometry Zoe Scott, Cornell University, Ithaca |
| 4:30 pm – 4:50 pm | High-Throughput Tannin Fragmentation Fingerprinting Links Chemistry to Astringency Yanxin Lin, The Pennsylvania State University, State College |
Dallas Parnigoni | Federico Casassa* | Sean Kuster | Bob Coleman | James Nelson | Jesus Villalobos
Effects of Contrasting Cap Management on ORP, Phenolic, and Volatile Outcomes in Pinot noir and Petite Sirah Wines
Dallas Parnigoni , Federico Casassa,* Sean Kuster, Bob Coleman, James Nelson and Jesus Villalobos
*Wine and Viticulture Department – Cal Poly San Luis Obispo, 1 Grand avenue , San Luis Obispo, CA, 93407, lcasassa@calpoly.edu
Pinot noir and Petite Sirah wines were produced using five and six cap management protocols: punch-downs (PD, twice daily); pump-overs (PO, two full volumes, twice daily); and gas mixing executed by gas injections into must: air mixing (AirMix, 1 hr, twice daily), nitrogen mixing (N₂Mix; 1 hr, twice daily); ORP-control through air additions (ORPConAir; 10-sec air when ORP < -40 mV); and in Pinot noir only, simultaneous N₂ additions coinciding with ORPConAir (ORPConN₂; 10-sec N₂). Oxidation-reduction potential (ORP), reduced glutathione (GSH), and oxidized glutathione (GSSG) were monitored throughout a 10-day alcoholic fermentation. In both varietals, average ORP values were similar between PD and PO wines; however, PO wines exhibited peaks ≥100 mV during pump-overs, while PD wines maintained a negative ORP at peak fermentation, even during punch-downs. At pressing, N2Mix wines showed GSH:GSSG ratios of 6.6:1 and 5.0:1, while PD wines showed ratios of 0.7:1 and 1.3:1 in Pinot noir and Petite Sirah, respectively. At pressing, there were no differences in anthocyanin or tannin in any treatment other than AirMix wines in either varietal. Alternatively, AirMix wines showed reductions in total phenolics at pressing of 21% and 30% compared to PD wines in Pinot noir and Petite Sirah, respectively. Compared to PO wines, PD wines had increased flavan-3-ols by 48% and 8% in Pinot noir and Petite Sirah, respectively. Ethyl n-octanoate had the greatest odor activity values (OAV) in all treatments of Pinot noir, ranging from 147 (PO) to 116 (AirMix), while isoamyl acetate was most odorous in Petite Sirah, ranging in OAV from 248 (ORPConAir) to 120 (AirMix). These cap management protocols produced unique ORP evolutions, influenced GSH:GSSG ratios, and differentially affected phenolic and volatile composition, with consistent trends despite varietal differences.
Funding Support: Gallo
