The exact rules around calling a wine organic change from region to region, but generally speaking, wineries that produce organic wine cannot use toxic pesticides, herbicides or synthetic fertilizers to grow grapes. The main point of variation between organically grown and certified organic has to do with the use of sulfites. In the US, certified organic wines cannot use SO2 in their winemaking process. Canadian and European (labelled ‘bio’) wines, may contain added sulfites.