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 secondary sector of the economy. The term may refer to ...

process or

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking ...

; 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, which is a byproduct of the milling of

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

into refined flour, is sometimes composted or burned for disposal, but in other cases, it can be used as a nutritious ingredient in

human food Humans eat various food substances for enjoyment and nutritional support. It is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. Omnivorous humans are high ...

or animal feed.

Gasoline Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic c ...

was once a byproduct of oil refining that later became a desirable commodity as motor fuel. The plastic used in plastic shopping bags also started as a by-product of oil refining.

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): ''Cos ...

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 (I ...

(NRV) when compared with the main products". Because they are deemed to have no influence on reported financial results, by-products do not receive allocations of joint costs. 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 organisation, established in 1974, that provides policy recommendations, analysis and data on the entire global energy sector, with a recent focus on curbing car ...

(IEA) defines ''by-product'' in the context of life-cycle assessment 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 (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 that are not incorporated into the ''desired product'', as a consequence of conservation of mass; 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.

References

{{Authority control Recycling Product

In economics

In chemistry

See also

References