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Sweating/Fermenting and TSNA questions


May 10, 2020
Several questions about finishing process....
1. Can the leaves be heated to 185 degrees for a short time to kill off microbes and then be further aged/fermented to be used in cigars?
2. Is the "crock pot steam" method for fermenting and making cavendish basically the same as the "pastuerizing" that is done in making snus? From my understanding, either way the leaf is essentially cooked to kill off the microbes and after heating to 185 degrees they should pretty much be eliminated regardless of time spent cooking. Longer time=cavendish?
3. After air curing, would sweating leaves to a lower temp than 185 (example: in a plastic container in the sun for a few hours/ days until ammonia is released) provide a lower TSNA content than a slower, lower temp fermentation? Does higher temp simply=faster fermentation?
4. Does fermentation still take place while pressing if using tobacco that has been "steamed" or made into cavendish?
5. At what point during curing/aging does the TSNA levels rise? I have read that snus is typically processed soon after color curing to brown instead of further aging.
Just trying to clear up some confusion about this whole process and turn out a product with low TSNA without using a specific LC variety. Regardless, the little dutch and ahus should turn out well in the end!


Staff member
May 25, 2011
near Blacksburg, VA
Welcome to the forum. Feel free to introduce yourself in the Introduce Yourself forum.

A search of this forum for "TSNA" will provide you with a lot of material.
  1. Fermentation / Aging in all tobacco is the result of the action of intrinsic enzymes within the leaf lamina. The primary oxidizing enzyme is denatured (permanently destroyed) at 141°F. The secondary (slower and less efficient) oxidizing enzyme is denatured around 191°F. The purpose of flue-curing is to nuke the primary oxidase, then dry the leaf completely, in order to abruptly halt fermentation / aging. ANSWER: No
  2. Steam cooks. Cooked tobacco denatures the oxidizing enzymes. Cooking (Cavendish method) is not fermentation. Pasteurization is a specific process at a specific temperature for suppressing food pathogens, without cooking. ANSWERS: No; Conflating cooking with aging.
  3. You really need to read about color-curing and fermentation on the forum. ANSWER: No.
  4. After tobacco has been cooked, the only possible fermentation is that caused by introduced microbes. ANSWER: It depends.
  5. TSNA's are a complex issue. If you plan to suck on the tobacco or inhale its smoke, then TSNA's are of concern. And the easiest approach is to plant low-converter (LC) tobacco (from which the seed cannot be saved, since it reverts to non-LC). In flue-curing, avoid mixing the combustion products of the heating fuel (the exhaust) with the ventilation air within the chamber. "Snus" is a bunch of different things produced in different ways by different manufacturers.
Sorry I can't be more helpful.

Perhaps if you explain what use you intend for your tobacco, we could reply more specifically.