Issue link: http://winesandvines.uberflip.com/i/63937
WINEMAKING Closure 1 + 1 (A) 1 + 1 (B) Micro Agglomerate Agglomerated Natural cork (Grade 1) Natural cork (Grade 2) Natural cork (Grade 3) Plastic (A) Plastic (B) Plastic (C) Screwcap No. of Bottles 126 18 18 18 54 36 90 90 18 54 18 Total: 540 a rule). As a rule, 1mg/L of oxygen will consume 4mg/L of free sulfur dioxide, so if oxygen pickup at bottling (which can vary widely and is often as high as 3 or 4mg/L), or closure oxygen transmission is high, then quite a bit of SO2 will be used up, and the risk of oxidation will increase. When the data from this study are ana- lyzed by closure type (table above), the Min 34 75 82 49 6 5 26 21 72 21 101 5 Analysis by Closure Type Total SO2 Max (mg/liter) Mean 99 75.61 79 76.67 99 94.67 66 60.00 59 39.76 74 51.25 115 67.36 116 72.38 77 74.89 133 67.52 114 109.50 133 68.93 SD 18.55 1.33 4.27 4.52 10.50 19.61 25.32 33.58 1.23 44.94 4.15 28.46 Min 11 21 18 19 6 3 2 3 17 7 16 2 sample sizes become quite small, but the data do indicate that the technical corks (one plus ones and agglomerates) and screwcaps perform much more consistent- ly than the natural cork (to be expected) and synthetics (a surprise, because these are manufactured and therefore presum- ably quite uniform.) More data would be needed to draw firm conclusions here, Free SO2 Max (mg/liter) Mean 30 20.60 24 22.44 30 25.56 27 23.78 28 14.11 26 15.23 40 17.53 44 20.59 23 20.22 32 17.04 27 20.67 44 41.91 TCA 5.27 0.86 2.57 2.18 4.16 9.27 7.52 13.16 1.31 7.32 3.07 8.07 SD % Tainted 5.6% 0.0% 11.1% 5.6% 5.6% 8.3% 6.7% 5.6% 0.0% 5.6% 0.0% but this message will be good news for DIAM, even though no DIAM closures were involved in the trial. The startling results of this trial prove that bottle variation is an issue the wine industry needs to address. Jamie Goode is a London-based wine writer who is currently the wine columnist with the UK national newspaper The Sunday Express. Wines & Vines MAY 2012 61