Distillers grains are a
cereal
A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food ...
byproduct
A by-product or byproduct is a secondary product derived from a production process, manufacturing process or chemical reaction; it is not the primary product or service being produced.
A by-product can be useful and marketable or it can be consid ...
of the
distillation
Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the he ...
process. Brewer's
spent grain usually refers to
barley
Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...
produced as a byproduct of brewing, while distillers grains are a mix of corn, rice and other grains.
There are two main sources of these grains. The traditional sources were from brewers. More recently,
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
biofuel plants are a growing source. It is created in
distilleries
Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heat ...
by drying
mash, and is subsequently sold for a variety of purposes, usually as
fodder
Fodder (), also called provender (), is any agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, rabbits, sheep, horses, chickens and pigs. "Fodder" refers particularly to food given to the animals (includ ...
for
livestock
Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to ani ...
(especially
ruminants
Ruminants (suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The ...
).
Corn
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The ...
-based distillers grains from the ethanol industry are commonly sold as a high protein livestock feed that increases efficiency and lowers the risk of subacute acidosis in beef cattle.
Recently, studies indicate that dried distillers grains with solubles (DDGS) as a food source for ''human consumption'' may have some benefit in reducing heart disease risk. The mash left over from the process contains nutrients, such as protein, fiber, germ, vitamins, and minerals, and research suggests that the flour made from DDG will work well with cookies and flatbread. The texture and taste of food-grade DDG, especially corn, has been compared to breakfast cereal.
Wet and dry distillers grains
There are two common types of distillers grains:
* Wet distillers grains (WDG) contain primarily unfermented grain residues (protein, fibre, fat and up to 70% moisture). WDG has a shelf life of four to five days. Due to the water content, WDG transport is usually economically viable within 200 km of the ethanol production facility.
* Dried distillers grains with solubles (DDGS) is WDG that has been dried with the concentrated thin stillage to 10–12% moisture. DDGS have an almost indefinite shelf life and may be shipped to any market regardless of its proximity to an ethanol plant. Drying is costly, as it requires further energy input. In the US, it is packaged and traded as a commodity product.
Production
In beer or whiskey production, grains, such as corn, are put through a
mashing
In brewing and distilling, mashing is the process of combining a mix of ground grains – typically malted barley with supplementary grains such as corn, sorghum, rye, or wheat – known as the " grain bill" with water and then heating the m ...
process, where grain is ground and added to hot water. The starch in the grains undergoes saccharification by enzymes, turning the starch into sugars that are released into the water. The water is removed from the grain, and becomes
wort
Wort () is the liquid extracted from the mashing process during the brewing of beer or whisky. Wort contains the sugars, the most important being maltose and maltotriose, that will be fermented by the brewing yeast to produce alcohol. Wort als ...
for brewing. The remaining grain, called "spent grain" for the removal of simple sugars and starch, can then be sold as a by-product.
The conversion rate of grains to ethanol and distillers grains varies with the different types of grains and the process used. The details are outlined below:
* The conversion rate of corn to distillers grains is: One
tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
of corn produces 378 L of ethanol and 479 kg WDG (70% moisture content), or 309 kg of DDGS (10% moisture content).
* The conversion rate of wheat to distillers grains is: One tonne of wheat produces 372 L of ethanol and 457 kg WDG (70% moisture content), or 295 kg of DDGS (10% moisture content).
See also
*
Dietary fiber
Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by t ...
*
Sake kasu
or sake lee is a cooking ingredient that is white in color with a paste-like texture. The taste of sake kasu is fruity and has a similar taste to Japanese sake. Sake kasu is the lees left over from sake production. It is a by-product of Japanes ...
References
External links
Information page from the University of Minnesota Ethanol Producer MagazineIowa Corn
Distilled drinks
Fodder
{{Agri-stub