Tony Ferrill":cqsls5ff said:
And do they heat the tobacco to seal the tins to begin with??I know next to nothing about packaging this product beyond stripping,tying hands and taking to the market-and they press Burley now,and have for 25 years :lol:
Tony
Tins that are vacuum sealed (all rectangular tins, and most of the flat round ones) are done in a vacuum chamber. Heat is not part of the sealing process. Only enough vacuum to ensure a seal is used - any more than that, and the tins would collapse when they're removed. There's still plenty of oxygen in them to allow whatever is going on to go on.
My tins, and probably all pull-top tins, are sealed at atmospheric pressure. There is no need for a vacuum, as the seal is mechanical, and very solid.
The aging process is actually a great deal more complex than it seems. In addition to some amount of biological activity, there's a cascade of organic chemical reactions taking place. Any change to the environment
inside the tins after the process begins will alter the balance of the reactions, and change the outcome. This isn't necessarily a bad thing, but it's certainly unpredictable.
When you open a tin/jar of aged tobacco, I advocate smoking it. It will begin to change as soon as air hits it, and oxidation can begin to alter the delicate chemical balance of the aged leaf. It's like opening a bottle of good wine, though not as rapid. Some "breathing" will usually improve it by allowing some of the less desirable volatiles to escape, but after a while, it begins to deteriorate. Tobacco is not as sensitive as wine, of course, but if you treat your tobacco in a similar fashion, you won't go wrong.
Once you open an aged tin, transferring the contents to a jar with a good seal will help to slow down the loss of volatile aromatic components, of course, but it's my opinion that once opened, the tobacco should be smoked. For this reason, I've always advocated smaller tins for aging, larger ones for smoking "young." (That's actually the reason I originally released the GLPease blends in 2oz tins only. The 8oz packaging was a result of customer demand from those who are not interested in cellaring, and prefer the convenience of the larger package.)