• noun any of various salts of sulphurous acid used as food preservatives.


  • a chemical compound of sulphur present in tiny quantities in some wines that typically have had sulphur used in them at some stage of the winemaking process – either sprayed onto the grapes on the vine as an insecticide or as sulphur dioxide used as a disinfectant to remove natural yeasts from a barrel, or added to a newly fermented wine to kill off all yeasts and prevent any further, secondary fermentation in the bottle. In some countries such as the US wine with more than 10 ppm of sulphur compounds must indicate this on the label to warn people allergic to sulphites.