the 2 steps of the tobacco expansion, first the tobaco sheets are frozen at the nearly -170, the it go to about +400 °Celsius.
That's what whe call the expansion tunnel.
so, it's in a simply way, what a lot of people smoke, the light tobacco.

sorry to put some picture about the tobacco industry, but I work a few year on the trainning department, so I whas thinking interresting to show how the industry his working at this 21 century.