steaming or pressure cooking?
What is the science behind both?
any regards for Temp. and pressure values and levels?
after steaming or pressure cooking, should tobacco be dried immediately ?
is there any need for pressing tobacco after that?
does all of this equally applicable for whole leaves and shredded?
My experience is that the principal difference between steaming and pressure-cooking is that the process is more rapid (though still many hours) with a pressure cooker. A standard pressure cooker valve weight permits the buildup of 15 psi (pounds per square inch), which raises the boiling point of water (at sea level) from 100°C to 121°C. The more
exposure to water, the darker the tobacco will get. An added benefit of using either method in a sealed canning jar (the lid allows excess pressure within the jar to vent) is that once the cooking is finished, regardless of method, the
sealed jar can be left unopened indefinitely, since its contents have been sterilized.
Once you open the jar, all the tobacco inside it should be removed, and dried to low case, so that it does not mold. Low case is slightly noisy when handled, and is barely flexible, though it does not shatter when handled.
You can do this with either whole leaf or with leaf that has already been shredded.
In the Index of Key Forum Threads, you can find a number of lengthy threads on the subject of making Cavendish.
For the growers, if they can allow their leaf to mostly yellow while still on the stalk, then sun-curing for 3 weeks may yield a better result. Even then, kilning such leaf significantly improves it.
Do look over the threads on building a kiln. [For example:
https://fairtradetobacco.com/thread...tal-wood-tobacco-kiln-flue-cure-chamber.5767/] A kiln can be an old, retired refrigerator or a custom built box--just something with insulation and the ability to seal fairly efficiently. A simple Crockpot (as small as 2.5 liters) can provide heat (and moisture, if the leaf is left exposed), and a digital controller can be purchased on-line for about $15 or $20. Every forum member who has set up a kiln, including myself, has found it to be less complicated or difficult than they expected, and has regretted not going ahead to create one sooner. The electrical connection is quite basic. My current kiln, totally custom built using all new materials, required a little over $100 and one weekend of labor.
In your market environment, kilned tobacco or Cavendish might be in demand.
Bob
EDTI: Pressing any tobacco alters it. So you'll have to experiment with that. I would say that it is not necessary.