Any assessment or discussion of Preservative Wines revolves nearly entirely around the absence of Sulphur Dioxide (SO2) or its wine label alter ego ‘added preservative 220’. It is important to note the use of the term ‘added’ as SO2 can be produced naturally during fermentation. So in this respect, technically speaking, any label proclaiming the wine to be ‘preservative free’ is not entirely accurate.

The good news is that the use of such additives appears to be on a downward trend. As winemaking and viticulture skills constantly improve the underlying fruit is in better condition and this lessens the need for sulphur dioxide to patch up any weak spots.

More details here.