How do you check the seal on tinned tobacco? I typically vacuums seal bagged tobacco like esoterica or anything that comes in square tins, Germain's, penzance etc. but rest of the stuff I just put in a zip lock bag and forget about them. I was going thru my cellar this past weekend and I can definitely smell the tobacco when I opened the ziplock bags. Is it safe to say the seal has been compromised? All the tins are at least 6-7 years old and most are discontinued dunhill blends. Should I vacuum seal them to be on the safe side? I'm hoping to keep them another 10-15 years.
I also have bunch of McClelland tubs, with those I assume as long as there are not visible damage to the tin they should be good to go, maybe?
By and large, canister tins, like the McClelland tins, are good for decades, as they used food grade tins for their product. But a number of McClelland smokers have reported a few of their older tins from the '90's having rotted through from the inside out. That said, it appears to be a tiny percentage. I've had a couple of failures with canister tins that were over 20 years old, both Rattray's where pressure from the inside had caused a failure along the scoring for the pop top. Other failures were with C&D tinnings of Haddo's, Raven's Wing, Renaissance, and Bohemian Scandal, from between 2000 and 2004, due to the crappy quality of the tins that were used. They literally rotted from the inside out. It is a crap shoot.
In general, round tins hold up quite well because the pressure is evenly distributed around the curving perimeter, but none of these were designed with decades long service in mind. The round tins often do hold up for decades, but don't count on it.
Square and rectangular tins are the worst designed for long term storage as there's no way to maintain an evenly distributed pressure around that shape. Gaskets can fail. They're losing a tiny amount of pressure from the get go, which is why you can smell the contents. They're usually good, in my personal experience, for a decade and then they start to fail. My experience with these tins after 30 years is that maybe 10% are still solid, but that's a small sampling. Still, it's why I consider any 1980's or thereabouts tin of "whatsis" that's up for sale to be a likely shelf ornament, and I don't spend $$$ for shelf ornaments.
For longer term peace of mind either jar, or heat seal in heavy grade food grade Mylar. Wherever you are storing your cellar, make sure that it is in a dry location so the tins don't rust out. Just accept that a percentage of your cellar, hopefully a small one, is going to go south on you no matter what you do.
