What an interesting question!
In a nutshell, hulls are removed by a ?slam and crack? process. Most
commercial dehullers force the seed along blades that slam the seed
against a part of the machine, causing the hull to crack open. After
the seed and hull are separated, the mix is ?winnowed?, causing the
hull to fall away, or to be blown or vacuumed away, depending upon the
method used by the machine. Other methods are more manual, as you will
see. In all methods that I found, it was important for the sunflower
seed to be dried. Moist seeds do not crack well, producing fewer
The National Sunflower Association says ?How are the hulls removed?
What is chew & spit? Very carefully! Actually there are machines that
have been developed, called impact dehullers, that do this job. Of
course, many people such as baseball players and truckers, as well as
folks of Asian or European decent, love to 'chew & spit.' In other
words, they put the whole sunflower seed (with the hull) into their
mouths and do their own hulling. These roasted and salted sunflowers
are a very tasty snack and can almost become addictive. It sure beats
There are several types of seed dehullers available worldwide. This
site describes an ?impact? method, where the seed is passed along a
blade, whereupon it collides with a wall, cracking the shell. The
loose hulls are then separated. This University of Pretoria site
explains it best, on Page 4 of this PDF:
Here are some Japanese dehullers, working on the same ?slam and crack?
theory. The kernels and hulls are separated by a ?winnowing?
machine.Winnowing machines blow away the lighter weight hull. The
second link explains making a home-made sunflower dehuller.
According to Peanut Sheller, ?Traditional shelling machines press the
nuts through slots to release the kernels from the shell. This works
well with nuts roasted in the shell, but poorly if they are
sun-dried.? You can see some small scale nut shellers on this site.
A BioMat de-huller prototype can be seen here:
Sunflower Seed de-huller equipment from Hper-Mart :
A flow chart of the vibrating and de-hulling process can be seen here:
This Garden Banter discussion site suggests ?Hand crank meat grinder
and a bucket of water.Nutmeats sink, hulls float.?
A grinder recommended by the above site:
Here is an interesting ?home? method of hulling sunflower seeds. The
native American woman (Buffalo Bird Woman) of the Hidatsa Indian Tribe
(ca.1839-1932) ?parches? the seeds, causing the shells to crack open,
releasing the seed.
A bit of information on sungflower dehulling:
A homemade dehuller:
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