Here's my limited personal experience.
Dan tobacco Limerick from 1999.
Opened around 2018-19. Jarred
Smoked occasionally and gifted samples.
Last bowl smoked this summer before giving the remainder to a friend.
Every bowl incredible.
C&D Kajun Kake from 2008
Opened 2018. Jarred
Special occasion smoke. Once or twice a year.
Every bowl excellent until summer 2020. It went ashy and harsh out of the blue. Never came back no matter what I tried.
There's a longer list of 10 or so year old tins with no adverse effects. Those are the two most prominent in my mind.
Who really knows. I think it depends on the blend.
Dan tobacco Limerick from 1999.
Opened around 2018-19. Jarred
Smoked occasionally and gifted samples.
Last bowl smoked this summer before giving the remainder to a friend.
Every bowl incredible.
C&D Kajun Kake from 2008
Opened 2018. Jarred
Special occasion smoke. Once or twice a year.
Every bowl excellent until summer 2020. It went ashy and harsh out of the blue. Never came back no matter what I tried.
There's a longer list of 10 or so year old tins with no adverse effects. Those are the two most prominent in my mind.
Who really knows. I think it depends on the blend.