These standardized laboratory
sizing / test sieves are quite expensive new but can be
found at bargain prices used. eBay is where I found
the above pieces.
Tobacco Seed Cleaning
After harvesting the tobacco
seed pods, they are then allowed to dry.
After completely dry, the
capsules are threshed and sieved through US Standard
Laboratory Sieves. 10 and 20 mesh (e.g. 100 and 400
holes per square inch respectively) are used to remove all
the coarse materials such as chaff, petals, and small stems.
The resulting seed is then
allowed to dry for several more days until a moisture
content of and five percent is achieved.
The seed is then cleaned by
sieving with a 30 mesh sieve and winnowed using a running
The sieve catches the small
chaff particles and the wind separates out the immature and
shriveled seed as well as fine particles of dust or chaff.
The seed is finally sieved
using a 40-mesh sieve. The seed that remains in the
sieve is the good seed and save and the fine dust passes