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58 W i n e s & V i n e s D e C e M B e R 2 0 1 4 of TPO for each bottle immediately after filling was calculated by combining O 2 in the headspace (HSO) plus oxygen dis- solved in the wine (DO). Headspace and filled wine volumes were used to compute TPO for a specific bottle as opposed to its adjacent fellows. This level of granularity had never before been imagined. Formation of the Collaborative Council In 2012, Nomacorc organized a panel of 40 industry experts including pro- duction winemakers, academic enolo- gists, quality-control specialists and winery research team leaders to oversee collaborative studies that might shed light on the sources and extent of TPO variation. The Wine Science Forum (WSF) advisory council now meets regu- larly to coordinate research, discuss results and organize seminars to share the group's work and solicit input from wine producers at large. Initial findings presented at the Confer- ence on Oxygen and Wine Quality in March 2013 were not encouraging. TPO was seen to vary typically by 1 mg/L within the spouts from a standard 30-spout filler. Research was presented to suggest that such variability caused differ- ences in freshness, fruit intensity and other key quality determinants in whites. Even in reds, where oxygen pickup can be beneficial, sensory effects also varied bot- tle to bottle. On the bright side, the NomaSense apparatus proved itself a valid scientific instrument, and the methodology of cal- culating TPO entered the mainstream of academic enological parlance. Getting serious Subsequent to the conference, the WSF advisory council determined that a more wide-reaching study of bottling variation should be undertaken that could account for variability in practices among produc- ers in order to gain a sense of the overall situation in the industry. The team formed to conduct the survey was led by Dr. Hend Letaief, newly recruited to California State University, Fresno, after cutting her teeth under leaders in the phenolics research field at the University of Montpelier. She was assisted by Ashley Heisey, one of Napa's most clued-in and meticulous winemak- ers. Added to this team were Pauline Martinaggi and Bertille Goyard, French interns on loan from ESA Angers School. Seventeen California wineries of varying size were chosen for an in-depth audit of a single day's bottling. Bottlings of nine red wines and eight white wines were studied. Wineries varied from 22 to 550 bottles per minute, employing between eight and 100 filler heads, and bottled volume ran from 525 gallons to 27,000 gallons. Eight runs employed natural corks, five used Noma- corc synthetic closures, one inserted agglomerated cork alternatives, and four were sealed with screwcap closures. Most wineries reported use of inert gas before and after the process; liquid nitro- gen drops and wine recirculation for priming also were evaluated. For each winery, dissolved oxygen (DO) was monitored throughout the day in the bottling tank bottom valve and at the filler at one, 50, 150, 300 and 500 bottles into the run as well as at the end. Indi- vidual bottles from up to 16 heads were assessed for HSO and DO at the begin- ning, middle and end of the run. Triplicate samples enabled estimation of error bars. As you will soon see, this beautiful study allows us to discriminate between measurement precision and actual sources of variability; between the noise of our instruments and the signals 707-938-1300 info@acrolon.com ® G R A P E G R O W I N G W I N E M A K I N G