Oxygen Transmission Through Different Closures Into Wine Bottles

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JULY/AUGUST 2007 1 PACKAGING Oxygen transmission through different closures into wine bottles

BY Paulo Lopes, Cédric Saucier, Pierre-Louis Teissedre, Yves Glories Faculté d’Oenologie de A Bordeaux, Université Victor 2.8 Segalen Bordeaux 2 UMR 1219 INRA. 2.3 Talence Cedex, France ) [email protected] L m (

1.8 n e g

geing of wine is extremely y x

dependent on the amount O 1.3 of oxygen 0a wine receives Aduring the winemaking 0.8 process.1 Opportunities for oxygen exposure include contact during 0.3 vinification prior to bottling, oxygen 0 3 691215 18 21 24 27 30 33 36 pick up during transfer to the filler, Horizontal storage (months) in the bottling line, in the headspace (dependent of volume, pressure, and 2.8 ) gas composition), and oxygen L m (

ingress through the closure during n 2.3 e g post-bottling storage. The latter y x

O B depends on the oxygen barrier pro- 1.8 vided by the closure used.

To summarize our experiment, a 1.3 non-destructive (a single bottle can be analyzed without compromising the closure seal) colorimetric 0.8 method was developed to measure oxygen ingress from 0.25 to 2.5 mL 0.3 0 3 691215 18 21 24 27 30 33 36 into wine bottles. This method infers Vertical storage (months) oxygen ingress through a closure by direct colorimetric scan of flint wine CONTROL FLOR GRADE FIRST GRADE bottles (375 mL) containing indigo TWIN TOP SUPREMECORQ NOMACORQ carmine solutions that gradually NEUTROCORK changes color from yellow to indigo as oxygen reacts with the reduced indigo carmine. This method mea- Figure I. Kinetics of oxygen ingress through different closures into wine bottles stored in horizontal position over 36 months (A) and vertical position over 28 months (B). Error bars sures the oxygen ingress through represent the standard deviation of four replicates. 2 JULY/AUGUST 2007 PACKAGING

different closures over the time Table I: Full ranges of oxygen ingress rates (µL/day) through screw caps, under identical conditions to wine “technical” and natural cork stoppers, and synthetic closures, during the bottle ageing. Details concerning this first month and the subsequent months of storage. methodology are provided in Lopes Storage et al.2 Closure Type First month Horizontal Vertical Closures tested include: two nat- a ural cork stoppers (45 x 24 mm), the Screw caps (tin liner) <500 0.2–0.7 — best grade (“flor”), and the interme- “Technical” corks 15–40 0.1–0.4 0.1–0.9 1.7–6.1b 0.5–4.4b diate grade (first); two “technical” Natural corks 25–45 0.1–2.3 c 0.1–2.7 c cork stoppers (Twin Top and Nomacorc synthetic closure 30–40 6 8–9 Neutrocork ); two synthetic closures, SupremeCorq synthetic closure 35–45 11–15 11–12 Nomacorc classic closure (43 x 22 a at moment of bottling b ™ from 2 to 12 months of storage mm) and Supremecorq 45 ; and four c different screw-cap (saran-tin liners) from 12 to 36 months (horizontal) and 12 to 28 months (vertical) storage closures (Stelvin, Auscap, Cospak, and CSA). barrier properties of each closure. per day), then rose gradually (0.1 to An airtight bottle containing a Probably, the important increase in 2.3 µL per day) until completion of reduced indigo carmine solution, color change during first month is the study at 36 months (Table I). sealed by flame, was used as a con- likely to be due to oxygen within clo- These data shows that natural corks’ trol. Four bottle replicates of each of sures that diffuses out of the closure permeation varied by a factor of 3.5 the sealing systems were assessed. during compression. The oxygen between two and 12 months and 23 All bottles were sealed and then entrained at fill was negligible (less in the following months, which are stored horizontally and vertically than 9µg/L, measured by polaro- substantially lower than the oxygen under constant temperature of 20 graphic probe). transmission rates and 1000-fold 1,4 +⁄–1ºC and constant relative humidity “Technical” cork stoppers (Twin variation reported by other studies. of 65 +⁄–1%. More details regarding Top and Neutrocork) exhibited a low The main reason for this differ- closures, bottling, and storage condi- level of oxygen permeation (0.1 to ence is the methodology used to 0.4 µL per day, Table I). In contrast, measure oxygen permeation of nat- tions are available in Lopes et al.3 synthetic closures, Nomacorc and ural corks (moisture-sensitive). Our This report provides results of the Supremecorq, exhibited the highest method measures oxygen ingress total oxygen ingress through differ- oxygen permeation, reaching a limit through natural corks inserted in ent cylindrical and screw-cap clo- of quantification for our method (2.5 commercial glass bottles filled with sures into wine bottles after bottling mL of oxygen) within 140 and 290 an aqueous indigo carmine solution, up to 36 and 18 months of horizontal days, respectively (Figure IA). while the Mocon method, used by storage, respectively. The impact of Natural cork stoppers exhibited other researchers, is based on mea- bottle orientation over 28 months of medium levels of oxygen perme- surement of oxygen transmission storage was also assessed. ation. On average, the best grade of rates through corks inserted in a cut Results natural cork stoppers (“flor”) exhib- bottleneck without liquid contact. Figure I shows the kinetics of oxy- ited lower oxygen ingress than the The contact with liquid is an gen ingress through different clo- intermediate one (first grade) important factor in oxygen transmis- sures into wine bottles stored hori- (Figure IA). This latter grade pre- sion through corks irrespective of zontally and vertically over 36 and sented some variability among four bottle orientation. Even in upright 28 months, respectively. It can be replicates, which can perform as storage, the relative humidity inside observed that only the control (bottle well as the natural “flor” grade or a bottle is maintained at 100%, sealed by flame) was completely air- similar to the less permeable Noma- which allows the absorption of con- tight, while other closures were per- corc synthetic closures. siderable amounts of moisture by meable to oxygen. Oxygen pickup The oxygen permeation patterns the corks. through cylindrical closures was for natural corks differed from other Oxygen diffusion through screw- much more important in the first closures. Generally, oxygen ingress cap closures differed from cylindri- month than in the following months through natural corks decreased cal closures. The apparent entry of of storage. This latter period was over time, mainly between the sec- oxygen into wine bottles was sub- extremely dependent on the oxygen ond and twelfth month (1.7 to 6.1 µL stantially higher during bottling JULY/AUGUST 2007 3 PACKAGING

than in the following 18 months of months of storage, only the control Judging by our findings and other storage. This appeared to be due to bottle (bottle sealed by flame) was recent research, it is clear that ageing the insertion of oxygen contained air-tight. Other closures displayed of wine in bottle occurs under micro- within the screw-cap in bottle head- different levels of oxygen perme- oxygenation. However, the current space at the time of sealing. After ation: low in screw-caps and “tech- issue is how much oxygen trans- bottling, screw-caps allowed the nical” corks, intermediate in conven- mission is required from a closure ingress of consistent low amounts of tional natural cork stoppers, and for wines to age correctly in bottle, oxygen (0.2 to 0.6 µL per day, Table I) high in synthetic closures. without oxidation or reduction prob- with no significant differences between manufacturers. The different oxygen barrier properties of each type of closure tested explain the large divergence in composition and sensory properties of wines sealed with different closures reported by several recent studies.5,6,7 These studies showed that oxygen ingress rates exhibited by synthetic closures, result in wines with a high level of browning and high-oxidized aroma scores. On the other hand, too low oxygen ingress rates, as shown by screw-cap closures and glass ampoules, promotes the develop- ment of rubbery or struck flint sul- fide-like aroma characters (post-bottling reduction). Generally, cork stoppers presented intermediate performance.6, 7 Another finding was that bottle storage orientation (upright or lying down) had little impact on oxygen ingress through most of the closures into wine bottles, at least over the first 28 months of the experiment under controlled conditions of temperature and humidity (Figure IB, Table I). These results agree with those recently reported by G. K. Skouroumounis et al. showing that no storage effect on the composition and sensory properties of white wines over five years, when the storage conditions are constant and controlled.7

Conclusion Different closures and sealing systems tested in this study resulted in a large divergence of oxygen barrier properties. After 18, 28, and 36 4 JULY/AUGUST 2007 PACKAGING

2.8 ) L

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e 1.8 g y x 1.3 O

0.8

0.3 0 24 6 810 12 14 16 18 Bottle #1 [left] (control) contains indigo Horizontal storage (months) carmine solution after 36 months of horizontal storage. Bottle #2 contains STELVIN AUSCAP COSPAK CSA indigo carmine solution sealed with “technical” Netrocork® cork stopper after Figure II. Kinetics of oxygen ingress through screw cap closures into wine bottles stored 36 months of horizontal storage. Bottle #3 horizontally during 18 months. Error bars represent the standard deviation of four replicates. contains indigo carmine solution sealed with natural cork stopper after 36 months of horizontal storage. Bottle #4 [right] consumer in optimal condition – the Robinson. “Wine bottle closures: physi- contains indigo carmine solution sealed wine, the closures and other packaging cal characteristics and effect on composi- with Nomacorc Classic® synthetic closure variables. A review of AWRI research tion and sensory properties of a after 10 months of horizontal storage. examining the changes that occur in Semillion wine. Performance up to 20 wine after bottling.” Wine Industry months post-bottling.” Aust. J. Grape & lems. This will depend on grape Journal 2005, 20 (4), 20–30. Wine Res. 2001, 7, 62105. varieties, winemaking practices, bot- 2. Lopes, P., C. Saucier, Y. Glories. 6. Francis, L., J. Field, M. Gishen, A. tling procedure, closure perfor- “Nondestructive colorimetric method to Coulter, P. Valente, K. Lattey, P. Hoj, E. mance, and storage conditions. determine the oxygen diffusion rate Robinson, P. Godden. “The AWRI clo- The bottom line is that only a bet- through closures used in winemaking.” sure trial: sensory evaluation data 36 ter understanding of the wine chem- J. Agric. Food Chem. 2005, 53, 6967–6973. months after bottling.” Aust. & New Zeal. istry and the sources of oxygen will 3. Lopes, P., C. Saucier, P.L. Teissedre, Grapegrower & Winemaker 2003, 475, enable us to determine the optimal Y. Glories. “Impact of storage position on 59–64. amount of oxygen needed for wine oxygen ingress through different clo- 7. Skouroumounis, G. K., M. J. Kwiat- to develop properly in the bottle. n sures into wine bottles.” J. Agric. Food kowski, I.L. Francis, H. Oakey, D. References Chem. 2006, 54, 6741–6746. Capone, B. Duncan, M. A. Sefton, E. J. 1. Godden, P., K. Lattey, L. Francis, 4. Hart, A., A. Kleinig. “The role of Waters. “The impact of closure type and M. Gishen, G. Cowey, M. Holdstock, E. oxygen in the aging of bottled wine.” storage conditions on the composition, Robinson, E. Waters, G. Skouroumounis, Wine Press Club of New South Wales INC. colour and flavour properties of a M. Sefton, D. Capone, M. Kwiatkowski, 2005, 1–14. www.winepressclub.com.au Riesling and a wooded Chardonnay J. Field, A. Coulter, N. D’Costa, B. 5. Godden, P., L. Francis, J. Field, M. wine during five years’ storage.” Aust. J. Bramley. “Towards offering wine to the Gishen, A. Coulter, P. Valente, P. Hoj, E. Grape & Wine Res. 2005, 11, 369–384.

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