Huller

A huller is a device or machine used to remove hulls (husks) from seeds, grains, legumes, or nuts. The term can also refer to a person who performs hull removal, but in common usage it denotes equipment employed in agricultural and food-processing operations to separate the outer covering from the edible kernel.

Most hullers operate by mechanical action that loosens or abrades the hull, sometimes using friction, impact, or water flotation to separate hull from kernels. Common types include abrasive hullers, which wear away the hull surface; impact hullers, which strike kernels to detach hulls; and friction/dehulling rollers that rub hulls away. For some crops there are crop-specific machines, such as rice dehullers, peanut or almond hullers, sesame hullers, and coffee hulling machines that remove parchment or husk after drying.

Applications: In rice milling, dehulling is used to remove the protective husk from paddy to produce brown rice or milled rice; in coffee processing, hulling is the step that removes parchment and silver skin; in oilseed processing, hullers separate hulls from seeds such as rapeseed or sunflower to produce edible kernels and separate husk byproducts; in legumes and nuts, hullers improve texture and digestibility.

Design considerations include crop type, required kernel integrity, throughput capacity, and the acceptable level of broken kernels. Modern hullers are often integrated into automated processing lines with cleaning, separating, and polishing stages. Materials of construction range from wear-resistant steels to ceramics or elastomers, and many units are designed for sanitation and easy cleaning.

See also: Dehulling, Dehusking, Sheller, Hulling (process).