JULY/AUGUST 2007 1 PACKAGING transmission through different closures into

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 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 , Horizontal storage (months) in the , in the headspace (dependent of volume, pressure, and 2.8 ) gas composition), and oxygen L m (

ingress through the 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 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 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 ( 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 varied by a factor of 3.5 the sealing systems were assessed. during compression. The o