Sulfites are natural by-product of the fermentation process that act as a preservative against certain bacteria. A short fermentation process doesn’t produce enough sulfites-to preserve a wine for more than a few weeks. which is why added sulfites are necessary. Wine ranges from about 5ppm (5 parts per million) to about 250ppm/L. The legal limit in the US is 350ppm g/L. We are transparent, that is why you will find the filling date on our Mr and Mrs SYLTBAR bottles.