A rice huller or rice husker is an agricultural machine used to automate the process of removing the

chaff Chaff (; ) is the dry, scaly protective casing of the seeds of cereal grains or similar fine, dry, scaly plant material (such as scaly parts of flowers or finely chopped straw). Chaff is indigestible by humans, but livestock can eat it. In agri ...

(the outer

husk Husk (or hull) in botany is the outer shell or coating of a seed. In the United States, the term husk often refers to the leafy outer covering of an ear of maize (corn) as it grows on the plant. Literally, a husk or hull includes the protective ...

s) of grains of

rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domesticat ...

. Throughout history, there have been numerous techniques to hull rice. Traditionally, it would be pounded using some form of

mortar and pestle Mortar and pestle is a set of two simple tools used from the Stone Age to the present day to prepare ingredients or substances by crushing and grinding them into a fine paste or powder in the kitchen, laboratory, and pharmacy. The ''mortar'' ( ...

. An early simple machine to do this is a

rice pounder A rice pounder is an agricultural tool, a simple machine that is commonly used in Southeast Asia to dehull rice or to turn rice into rice flour. The device has similar functionality to a mortar and pestle, but with more mechanical advantage to ...

. Later even more efficient machinery was developed to hull and polish rice. These machines are most widely developed and used throughout

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

where the most popular type is the Engelberg huller designed by

German Brazilian German Brazilians (German: ''Deutschbrasilianer'', Hunsrik: ''Deitschbrasiliooner'', pt, teuto-brasileiros) refers to Brazilians of full or partial German ancestry. German Brazilians live mostly in the country's South Region, with a smaller bu ...

engineer

Evaristo Conrado Engelberg Evaristo Conrado Engelberg (26 October 1853–1932) was a Brazilian mechanical engineer and inventor. He is the inventor of the Engelberg huller, a machine used to strip the husks from rice and coffee during harvest. He was born to German i ...

in Brazil and first patented in 1885. The Engelberg huller uses steel rollers to remove the husk. Other types of huller include the disk or ''cono'' huller which uses an abrasive rotating disk to first remove the husk before passing the grain to conical rollers which polish it to make

white rice White rice is milled rice that has had its husk, bran, and germ removed. This alters the flavor, texture and appearance of the rice and helps prevent spoilage, extend its storage life, and makes it easier to digest. After milling ( hulling), t ...

; this is done repeatedly since other sides of circular side of rice are not husked. Rubber rollers may be used to reduce the amount of breakage of the grains, so increasing the yield of the best quality ''head rice'', but the rubber rollers tend to require frequent replacement, which can be a significant drawback.

Sample mechanism for the husk

References

{{commonscat, Rice hulling Agricultural machinery

Sample mechanism for the husk

See also

References