A by-product or byproduct is a secondary product derived from a production process,

manufacturing Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of the secondary sector of the economy. The term may refer ...

process or

chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

; it is not the primary product or service being produced. A by-product can be useful and marketable or it can be considered waste: for example,

bran Bran, also known as miller's bran, is the component of a Cereal, cereal grain consisting of the hard layersthe combined aleurone and Fruit anatomy#Pericarp layers, pericarpsurrounding the endosperm. Maize, Corn (maize) bran also includes the p ...

, which is a byproduct of the

milling Milling may refer to: * Milling (minting), forming narrow ridges around the edge of a coin * Milling (grinding), breaking solid materials into smaller pieces by grinding, crushing, or cutting in a mill * Milling (machining), a process of using ro ...

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

into refined

flour Flour is a powder made by Mill (grinding), grinding raw grains, List of root vegetables, roots, beans, Nut (fruit), nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredie ...

, is sometimes

compost Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical, and biological properties. It is commonly prepared by Decomposition, decomposing plant and food waste, recycling organic materials, and man ...

ed or burned for disposal, but in other cases, it can be used as a nutritious ingredient in

human food Human food is food which is fit for human consumption, and which humans willingly eating, eat. Food is a basic necessity of life, and humans typically seek food out as an instinctual response to hunger (physiology), hunger; however, not all thing ...

animal feed Animal feed is food given to domestic animals, especially livestock, in the course of animal husbandry. There are two basic types: fodder and forage. Used alone, the word ''feed'' more often refers to fodder. Animal feed is an important input ...

Gasoline Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...

was once a byproduct of

oil refining An oil refinery or petroleum refinery is an industrial processes, industrial process Factory, plant where petroleum (crude oil) is transformed and refining, refined into products such as gasoline (petrol), diesel fuel, Bitumen, asphalt base, ...

that later became a desirable commercial

product Product may refer to: Business * Product (business), an item that can be offered to a market to satisfy the desire or need of a customer. * Product (project management), a deliverable or set of deliverables that contribute to a business solution ...

motor fuel A motor fuel is a fuel that is used to provide power to the engine of motor vehicles — typically a heat engine that produces thermal energy via oxidative combustion of liquid or gaseous fuel and then converts the heat into mechanical energy ...

. The plastic used in

plastic shopping bag In use by consumers worldwide since the 1960s, shopping bags made from various kinds of plastic, are variously called plastic shopping bags, carrier bags, or plastic grocery bags. They are sometimes referred to as single-use bags—referring to c ...

s also started as a by-product of oil refining. By-products are sometimes called co-products to indicate that although they are secondary, they are desired products. For example, hides and leather may be called co-products of beef production. There is no strict distinction between by-products and co-products.

In economics

In the context of production, a by-product is the "output from a

joint production process In economics, joint product is a product that results jointly with other products from processing a common input; this common process is also called joint production.Wouters, Mark; Selto, Frank H.; Hilton, Ronald W.; Maher, Michael W. (2012): '' ...

that is minor in quantity and/or

net realizable value Net realizable value (NRV) is a measure of a fixed or current asset's worth when held in inventory, in the field of accounting. NRV is part of the Generally Accepted Accounting Principles (GAAP) and International Financial Reporting Standards (IFRS ...

(NRV) when compared with the

main products A main product is a joint output that generates a significant portion of the net realizable value (NRV) within a joint production process. The classification of a product resulting from a joint production process as either a main product or a by-p ...

". Because they are deemed to have no influence on reported financial results, by-products do not receive allocations of

joint cost Manufacturers incur many costs in the production process. It is the cost accountant's job to trace these costs back to a certain product or process (cost object) during production. Some costs cannot be traced back to a single cost object. Some costs ...

s. By-products also, by convention, are not inventoried, but the NRV from by-products is typically recognized as "other income", or as a reduction of

ing costs when the by-product is produced. The

International Energy Agency The International Energy Agency (IEA) is a Paris-based autonomous intergovernmental organization, established in 1974, that provides policy recommendations, analysis and data on the global energy sector. The 31 member countries and 13 associatio ...

(IEA) defines ''by-product'' in the context of

life-cycle assessment Life cycle assessment (LCA), also known as life cycle analysis, is a methodology for assessing the impacts associated with all the stages of the life cycle of a commercial product, process, or service. For instance, in the case of a manufact ...

by defining four different product types: "main products, co-products (which involve similar revenues to the main product), by-products (which result in smaller revenues), and

waste products Waste are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor economic value. A waste product may beco ...

(which provide little or no revenue)."

In chemistry

While some chemists treat "by-product" and "side-product" as synonyms in the above sense of a generic secondary (untargeted) product, others find it useful to distinguish between the two. When the two terms are distinguished, "by-product" is used to refer to a product that is not desired but inevitably results from molecular fragments of starting materials and/or

reagents In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

that are not incorporated into the ''desired product'', as a consequence of

conservation of mass In physics and chemistry, the law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter the mass of the system must remain constant over time. The law implies that mass can neith ...

; in contrast, "side-product" is used to refer to a product that is formed from a competitive process that could, in principle, be suppressed by an optimization of reaction conditions.

Common byproducts

bagasse Bagasse ( ) is the dry pulpy fibrous material that remains after crushing sugarcane or sorghum stalks to extract their juice. It is used as a biofuel for the production of heat, energy, and electricity, and in the manufacture of pulp and building ...

and

molasses Molasses () is a viscous byproduct, principally obtained from the refining of sugarcane or sugar beet juice into sugar. Molasses varies in the amount of sugar, the method of extraction, and the age of the plant. Sugarcane molasses is usuall ...

from sugar production *

and

germ Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embry ...

from flour milling *

buttermilk Buttermilk is a fermented dairy drink. Traditionally, it was the liquid left behind after churning butter out of cultured cream. As most modern butter in Western countries is not made with cultured cream but uncultured sweet cream, most mode ...

from butter production *

distillers grains Distillers grains are a cereal byproduct of the distillation process. Brewer's spent grain usually refers to barley produced as a byproduct of brewing, while distillers grains are a mix of wheat, maize, rice and other grains. There are two ...

from ethanol production *

fly ash Coal combustion products (CCPs), also called coal combustion wastes (CCWs) or coal combustion residuals (CCRs), are byproducts of burning coal. They are categorized in four groups, each based on physical and chemical forms derived from coal combust ...

and

bottom ash Bottom ash is part of the non- combustible residue of combustion in a power plant, boiler, furnace, or incinerator. In an industrial context, it has traditionally referred to coal combustion and comprises traces of combustibles embedded in for ...

from coal combustion *

glycerol Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

from soap or biodiesel production *

lanolin Lanolin (from Latin 'wool', and 'oil'), also called wool fat, wool yolk, wool wax, sheep grease, sheep yolk, or wool grease, is a wax secreted by the sebaceous glands of wool-bearing animals. Lanolin used by humans comes from domestic sheep br ...

from wool processing * lees from wine fermentation *

pomace Pomace ( ), or marc (; from French ''marc'' ), is the solid remains of grapes, olives, or other fruit after pressing (wine), pressing for juice or Vegetable oil, oil. It contains the skins, pulp, seeds, and stems of the fruit. Grape pomace has ...

from fruit juice or olive oil production *

saw dust Sawdust (or wood dust) is a by-product or waste product of woodworking operations such as sawing, sanding, milling and routing. It is composed of very small chips of wood. These operations can be performed by woodworking machinery, portable po ...

from lumber production *

slag The general term slag may be a by-product or co-product of smelting (pyrometallurgical) ores and recycled metals depending on the type of material being produced. Slag is mainly a mixture of metal oxides and silicon dioxide. Broadly, it can be c ...

from smelting ore *

straw Straw is an agricultural byproduct consisting of the dry wikt:stalk, stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the crop yield, yield by weight of cereal crops such as barley, oats, rice, ry ...

from grain harvesting *

trub Trub is one of the largest municipalities of Switzerland (62 km²) in size, but not in population. It is located in the Emmental region of the Cantons of Switzerland, canton of Bern (canton), Bern in the administrative district of Emmental ( ...

from beer fermentation *

vinasse Vinasse is a byproduct of the sugar or ethanol industry. Sugarcane or sugar beet is processed to produce crystalline sugar, pulp and molasses. The latter are further processed by fermentation to ethanol, ascorbic acid or other products. Juice sugar ...

from sugar or ethanol production *

whey Whey is the liquid remaining after milk has been curdled and strained. It is a byproduct of the manufacturing of cheese or casein and has several commercial uses. Sweet whey is a byproduct resulting from the manufacture of rennet types of hard c ...

from cheese production

References

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In economics

In chemistry

Common byproducts

See also

References

References