Issue link: http://winesandvines.uberflip.com/i/877508
October 2017 WINES&VINES 51 PRACTICAL WINERY & VINEYARD WINEMAKING Inerting of the empty bottle before filling can reduce DO as much as 0.5 ppm. With new equipment and/or good settings, the level can be very low, with a pickup below 0.5 ppm. DO variation between bottles has to be as low as possible, and we recommend less than 0.3 ppm difference as a target. In the end, DO in bottled wines should be lower than 1 ppm. Manage headspace oxygen level and consistency Oxygen in the headspace (HSO) is another critical point during bottling. According to our data, it usually represents more than 50% of the TPO, which makes it the biggest reser- voir of oxygen in a bottle. This is the biggest source of bottle-to-bottle variation. HSO measurement after corking is crucial to assess pickup and variability levels. In case of cylin- drical closures, the use of a vacuum system before corking is common practice to reduce the HSO level, but even with a good vacuum system the HSO would still be around 8%- 10% oxygen. If coupled with inert gas injec- tion, the HSO level can be decreased further, and bottles will contain as little as 0.2 ppm in the headspace. With screwcaps, the headspace volume is generally bigger, and a vacuum system cannot be used. As a consequence, these bottles generally contain higher HSO levels. In the best case, a generic inerting system can help reduce the average HSO level in screwcapped bottles from 5-6 ppm to 2-3 ppm, which is still quite high regarding post-bottling shelf-life management. To get a better HSO level in screwcapped bottles, we recommend using a system that has a double inert gas injection both inside the screwcap and bottleneck. TPO calculation and corrective actions Once HSO measurement is completed, TPO calculation can be performed to obtain an overall view of bottling line performance in terms of oxygen management. Vinventions recommends that the TPO should be less than 2 ppm for conventional wines and less than 1 ppm for low-sulfite wines. Thanks to each oxygen measurement done at the different steps of the bottling process, critical pickup stages can be identified and optimized. Even when best-in-class practices are in operation, frequent measurement re- mains necessary, as the right quality-control tool to ensure that the bottling line perfor- mance is always at its best. Magali-Eve Koralewski is an enologist who joined Vin- ventions in April 2014 as the enology department's technical writer to create technical content and com- munications from enological research and innovations developed by Vinventions' enology team. She previously spent six years as a journalist and chief of the enological rubric for Réussir Vigne, a French magazine specializing in viticulture and enology. The NomaSense O 2 P300 allows automatic TPO calculation by precisely measuring both dissolved and headspace oxygen.