A Tobacco Tinning Mystery Solved (At Least For Me).

[cosmicfolklore]

The weird thing is (I'm sure that there are weirder things, but follow me on this) The weird thing is that those of us who jar our tobaccos knows that you don't have to do anything to get a vacuum seal. I just put the tobacco in a jar, and a day or so latter, I have to use a lid pry to get the lid off. Years latter, it has the same vacuum seal. The concept behind this is that enzymes (magic bugs) uses up the oxygen. A lot of this comes from Greg Pease's writings.

But, on a tin of GLP's tobacco and some C&D stuff, the tins swell up with pressure, not a vacuum. I don't get this with any of my other tinned tobaccos. I have many tinned McClellands with no swelling, and they use the same sort of tins.
I am not exactly sure that a company would have to add vacuum, but I assume they do by the article I posted the link to. But, I am not sure it is needed as per my own experience with jarring tobaccos. But, what causes the swelling? I have seen posts and threads about this, but never anything clearly explained.

 

[jpmcwjr]

I reckon there's a touch of marketing when a blend is "vacuum sealed"; sounds more pro-y.
I can see why coffee cans were so sealed; air is really the enemy of coffee freshness, and the whoosh when opened was magical. Now I grind my own, fresh from the roaster, so haven't had that Folger's rush in decades.

 

[woodsroad]

Tins are vacuum packed primarily to assure a good lid to can seal. Sucking a little air out of the tin isn't going to do anything for "freshness" or long-term viability. If you want to give your jarred tobacco a head start on anaerobic fermentation, then add an oxygen absorber.
John, do you roast your own beans?