The internal pressure of a sealed vessel might be a consideration, but it would have to be a fairly weak jar to yield at only 160f.

Funnily enough I read in a growing guide that harsh tobacco can be moistened and thrown in the oven at 250f for ten minutes to make it smoother tasting, so I tried it with a couple bowls worth of Lanes 125th (because it's a fairly straighforward blend, and it was at the front of the cellar, and it was a free sample). Letting it rehydrate a bit overnight, so hopefully can compare the two. Smelled of pop tarts while in the oven - all those sweet VA sugars caramelising I guess.