A family member of mine has an extreme allergy to sulfates, so certain wines can cause unpleasant reactions such as headaches and swollen lips and throat. While there is a small amount of sulfates naturally occurring in the grapes, most winemakers also add extra sulfates in order to control fermentation, preventing the wine from becoming vinegar.
While there are sulfury compounds in whisky, according to Dr. Bill Lumsden (of Glenmorangie) the “only way there could be [sulfates] in whisky is if it’s wine or sherry barrels which have been treated with sulfur to sterilize them.” Sulfates are not needed to sterilize whisky, as the 40+% alcohol takes care of that concern. As such, if you get an allergic reaction to whisky, and think it is from sulfates, the only real possibility is that the whisky was fermented in wine or sherry casks which were cleaned or sterilized with sulfates. If in doubt, stick to Glenmorangie, who source their barrels from non-sulfate sources. Speaking of sources, this post inspired by WhiskyCast Episode 222.