Wines & Vines

October 2017 Bottles and Labels Issue

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50 WINES&VINES October 2017 WINEMAKING PRACTICAL WINERY & VINEYARD T otal package oxygen (TPO) manage- ment at bottling is crucial to avoid wine oxidation. According to bot- tling audits performed around the world, average TPO is 3 parts per million (ppm). This one-shot addition of 3 ppm at bottling may seem rather small, but when compared to what a closure brings per year—1 mg of oxygen in the case of a Noma- corc Select Green 100, for example—this potentially corresponds to three years of shelf life. It is important to take good care of TPO and develop strategies to control it in a con- sistent manner across the bottling process. Both dissolved oxygen (DO) in the wine and headspace oxygen (a function of oxygen percentage in the headspace and headspace volume), when combined, are the definition of TPO. How can low TPO be achieved? A key point is to measure O 2 regularly at different bottling steps. Measuring TPO regularly is the only way to accurately quantify critical oxygen pickup and identify TPO variations during the process. The most recognized way to measure it is to use the NomaSense O 2 P300 analyzer and a piercing system designed to facilitate real-time TPO measurements. Based on hundreds of bottling audits per- formed around the world, we developed a specific quality-control approach both on gas-management and bottling-line settings in order to help wineries achieve best-in-class bottling practices. Start with a low dissolved oxygen concentration in wine To achieve the lowest TPO, the first point to check is dissolved oxygen concentration in wine before the start of bottling. Measure- ment can be done directly in the tank with an immersion probe or using an oxygen sen- sor glued in a sightglass, allowing for a measurement during wine transfer. Our recommendation is to have a DO lower than 0.5 ppm in the tank. If higher, previous wine preparation steps (tartaric stabilization, fil- tration, etc.) may need to be better con- trolled and managed. Measurement can be done during these steps in order to identify where oxygen pickup occurs and then de- velop strategies to minimize pickup. Deoxy- genation of the wine can be a solution to decrease DO, but it has to be well executed without being detrimental to wine quality. Perform DO and CO 2 measurements at start of bottling The beginning of the bottling process can be a critical step for oxygen pickup. Hoses, the pump, filter, filler bowl and bottling line circuits are full of air and can generate consequent oxy- gen dissolution in wine and a large variation between bottles filled at the beginning of the run. At this stage of the process, both O 2 and CO 2 measurements are recommended to ensure better bottle-to-bottle consistency. Bottles of wine at the beginning of the bottling process often have more DO and less CO 2 . If high oxygen dissolution occurs, CO 2 loss can be important and generate a real impact on the aromatic profile, depending on wine style. DO control can be achieved after the pumps, the filters and before the filler bowl using a sightglass. Then final measurement can be performed directly using specially prepared sealed test bottles with sensors glued inside them. To avoid high DO levels and losses of dissolved CO 2 , the use of inert gas (prefer- ably a mix of nitrogen and CO 2 gases to retain the intended CO 2 level in wine) is recommended before priming the line. Even so, check the efficiency of the inerting method by measuring the O 2 level in hoses and the whole circuit to confirm it has been decreased to less than 2% before starting to pump wine into the system. Another solu- tion, depending on the bottling equipment, is to empty the first filled bottles back into the bottling tank to get a better consistency throughout the run. Check filling system performance Once priming is done, checking of each fill- ing valve and the inerting system of the empty bottle (if installed on the line) can be performed in order to assess the filling performance of the equipment. Both consis- tency and oxygen pickup can be assessed. Best Practices for Gas Management at Bottling Identify most critical oxygen pickup at bottling by measuring TPO By Magali-Eve Koralewski Image above: Frequent oxygen measurement at bot- tling is necessary for quality control.

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