![Rotary huller](https://upload.wikimedia.org/wikipedia/commons/a/af/Rotary_huller.jpg)
A rice huller or rice husker is an
agricultural machine
Agricultural machinery relates to the mechanical structures and devices used in farming or other agriculture. There are many types of such equipment, from hand tools and power tools to tractors and the countless kinds of farm implements that they ...
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
''Oryza glaberrima'', commonly known as African rice, is one of the two domesticated rice species. It was first domesticated and grown i ...
. 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 area ...
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 b ...
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), the ...
; 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
See also
*Rice hulls
Rice hulls (or rice husks) are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, or fuel. Rice hulls are p ...
*Rice polisher
A rice polisher is a machine for buffing (or "polishing") kernels of rice to change their appearance, taste, and texture or for transforming brown rice into white rice.
Rice polishers are used after the rice has gone through the whitening process ...
*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 ...
, an earlier simple tool to dehull rice
*Threshing machine
A threshing machine or a thresher is a piece of farm equipment that threshes grain, that is, it removes the seeds from the stalks and husks. It does so by beating the plant to make the seeds fall out.
Before such machines were developed, thre ...
, a general grain hulling machine
*Winnowing barn
Winnowing barns (or winnowing houses) were structures commonly found in South Carolina on antebellum rice plantations. A winnowing barn consists of a large shed on tall posts with a hole in the floor. Raw, husked rice was carried up into the barn ...
, a previous method of hulling in commercial rice growing
References
{{commonscat, Rice hulling
Agricultural machinery