Had to do my first dump today. I had opened a tin of SWS Moro Moro two days ago. Opened it today and it was loaded with fungus, both spidery-web and plain out mold. How often does this happen within a week of opening a can?
Furthermore in containers like Samuel Gawith uses - sealed - how do you know?
Sorry to hear that you lost your SWS. The moist, artisan-made snuffs like SWS Moro Moro should be refrigerated to keep them from spoiling. SG is much less of an issue in general, opened or unopened. The SGs, if a moist one, will probably fail due to a corroded tin (which spoila the snuff) before mold. The less moist ones can last many years - I believe my oldest is 7 and it’s still great snuff. The Artisan snuffs like @Johnny’s SWS are like a fine sports car. They provide a rich and unique experience but in turn require taking care of. At least, until there’s a Japanese snuff
Moist snuffs that are not vacuum sealed and have some sugar content are the most susceptible.