Dissolved Oxygen (DO)
Definition - What does Dissolved Oxygen (DO) mean?
In terms of wine, dissolved oxygen or DO is the amount of oxygen in the wine which is measured upon bottling; this is he final stage of wine-making at the winery. In this stage it is important to place the utmost care in protecting the wine micro-biologically and monitor it on the bottling line to ensure that only a minimum amount of dissolved oxygen is present in the wine. Too much and the wine can age quickly.
To keep a minimum of dissolved oxygen in the wine, it is important for the vessel to be "bubbled" with a gas; like that of nitrogen or argon.
WineFrog explains Dissolved Oxygen (DO)
Dissolved oxygen at minimum amounts is not perceivable and can benefit in the gradual and proper aging of your wine. It is said that it can be identified at 8.6 ppm (parts per million) which means that the wine is oxidized. The ideal amount of DO should be around 6 ppm.
While you cannot control the amount of dissolved oxygen or know how much is contained in the wine upon purchase, it is of little concern. The amount of oxygen which can enter the wine following bottling often depends on the closure and proper storage. Quality corks and Stelvin caps will preserve the wine the best from oxidation and early aging.
With proper storage, the wine can be cellared and aged properly. Keeping the wine bottle on its side will ensure the cork stays in contact with the wine and doesn't dry out, which can lead to leakage.