Last harvest, WBM added a set of winemaker's calculators to the winebusiness.com website. WBM's senior technical editor Curtis Phillips points out that most of the conversions and calculations you need in a professional winery can be found here.
In his column,"Calculating the Molecular SO2 in Wine," published in the January issue of Wine Business Monthly, Curtis notes:
"I would like to call particular attention to the tab for calculating the molecular SO2 in wine. When it comes to making wine, I think this could be the single most important calculator there is because although one can measure the pH and free SO2, the molecular SO2 is what is actually protecting your wine...
"I find that a distressing number of winemakers overlook the detail that it’s the molecular SO2, not the free SO2, that provides protection from spoilage microbes."