Wine closure on volatile sulfur and aroma development during post-bottle aging

AVF Proj. ID: 371 / /Cat.:
Primary Investigator(s): Michael Qian, J.P. Osborneby

About 900 bottles of Chardonnay and 900 bottles of Pinot noir wines were bottled at Argyle winery on August 15, 2007. Four (4) different closures (synthetic, Saran-tin, Saranex, polyethylene) with various oxygen permeabilities and two (2) natural corks (upright and inverted) were used. All of the wines were stored at the warehouse of Argyle winery at controlled temperature. An ACR Smart Reader Datalogger Plus was placed in one of the wine cases to record the temperature the wine is exposed to for the duration of the test. About 400 glass ampules were also filled with the same wines and hermetically sealed under argon. These samples were stored at 60°F as the control samples with zero air transmission.

The initial Charonnay wine had 25 mg/L free SO2 and 97 mg/L total SO2 while the initial Pinot noir
wine had 33 mg/L free SO2 and 68 mg/L total SO2. The initial oxygen was measured within five minutes of bottling. Sample bottles were taken at the beginning and end of each closure’s run. Headspace oxygen was measured by Oxysense 4000B and Oxypress w/ puncturing needle. Dissolved oxygen was measured with an Orbisphere 3650. The starting headspace and dissolved oxygen level was listed in Table.

Table 1. Starting headspace and dissolved oxygen level
Chardonnay Saranex LDPE Saran-tin Cork Up Cork Inv Synthetic
Hdspace (%02)
Start 8.9 5.5 12.4 16.4 14.7 7.9
End 12.5 8.6 12.2 15.6 16.1 5.2
Diss (ppb 02)
Start 121 112 111 91 76 68
End 110 108 97 80 72 65

Pinot Noir Saranex LDPE Saran-tin Cork Up Cork Inv Synthetic
Hdspace (%02)
Start 10.9 9.9 10.8 13.9 14.7 4.4
End 10.5 9.6 10.7 15.5 14.9 4.5
Diss (ppb 02)
Start 250 167 64 84 71 202
End 71 70 75 66 284 81

As shown in the table, slight pressure under natural corks increased Oxysense reading, while slight
vacuum under synthetic cork lowered Oxysense reading. In addition, the stop/start nature of this bottling process produced the variations in the beginning and ending headspace and dissolved oxygen readings. In steady-state bottling during the middle of the runs, the oxygen levels were likely the same as the lower readings recorded. The cork oxygen readings also do not take into account the amount of air that will escape the compressed corks after bottling. However, theses variation will be minimum compared with the total amount of oxygen transmission during the storage. The wines will be test for volatile sulfur compounds, volatile aroma compounds, oxygen and other parameters detailed in proposal at 6 months of storage.