By-products

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thumb|Bundles of rice straw thumb|Pile of stacked small rectangular straw bales sheltered under a clear tarpaulin thumb|Straw lines and a Combine Harvester|combine harvester Straw is an agricultural byproduct consisting of the dry stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield by weight of cereal crops such as barley, oats, rice, rye and wheat. It has a number of different uses, including fuel, livestock bedding and fodder, thatching and basket making.

Buttermilk is a dairy drink made by adding lactic acid bacteria to milk to produce a fermented dairy drink. Traditionally, it was made from the nearly fat-free milk remaining after churning butter from cream, which was cultured with natural bacteria prior to and during churning, giving a slight sour taste to the buttermilk. However, with the ubiquity of refrigeration in industrialized countries, butter in those areas is typically made from uncultured or "sweet" cream. Therefore, most modern buttermilk is specifically produced by inoculating fresh, pasteurized milk, and is available in differen

alt=A hazy cityscape to the right and a clear one to the left|thumb|Smog and a sunny day within a 10-day interval in Fanhe Town, Tieling|Fanhe, China

Glycerol () is a sugar alcohol with chemical formula . It has three carbon atoms and as many hydroxyl groups. It is a colorless, odorless, sweet-tasting, viscous liquid at Standard Ambient Temperature and Pressure (SATP). Because of its three hydroxyl groups, glycerol is miscible with water and is hygroscopic in nature.

thumb|upright=1.3|Community-level composting in a rural area in Germany

thumb|A handful of malted barley, the white sprouts visible thumb|Beer malt varieties from Bamberg, Germany

200px|thumb|A glass of soured milk whey Whey, also known as milk serum, 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 of the making of rennet types of hard cheese, like cheddar or Swiss cheese. Acid whey (also known as sour whey) is a byproduct of the making of acidic dairy products such as strained yogurt.

thumb|right|Sheet (or leaf) gelatin for cooking.

300px|thumb|The nest of the Peruvian booby is made of almost pure guano. thumb|Human-made Bird Island (Namibia)|Guano Island near [[Walvis Bay in Namibia]] Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a lesser extent, sought for the production of gunpowder and other explosive materials.

thumb|Emission of soot in the exhaust gas of a large diesel truck, without particle filters

thumb|300x300px|Wheat bran structure (E: outer layer; I: intermediate layer; A: aleurone layer) Bran, also known as '''miller's bran''', is the component of a cereal grain consisting of the outer hard layersthe combined aleurone and pericarpsurrounding the endosperm. Corn (maize) bran also includes the pedicel (tip cap). Along with the germ, it is an integral part of whole grains, and is often produced as a byproduct of milling in the production of refined grains. Bran is very nutritious, but is difficult to digest due to its high fiber content; its high fat content also reduces its shelf life

thumb|upright=1.15|Molten slag is carried outside and poured into a dump. Caletones copper smelter in El Teniente mine, Chile. Slag is 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 classified as ferrous (co-products of processing iron and steel), ferroalloy (a by-product of ferroalloy production) or non-ferrous/base metals (by-products of recovering non-ferrous materials like copper, nickel, zinc and phosphorus). Within these g

thumb|300px|Grapes being pressed to create must Must is freshly crushed fruit juice (usually grape juice) that contains the skins, seeds, and stems of the fruit. The solid portion of the must is called pomace and typically makes up 7–23% of the total weight of the must. Making must is the first step in winemaking. Because of its high glucose content, typically between 10 and 15%, must is also used as a sweetener in a variety of cuisines. Unlike commercially sold grape juice, which is filtered and pasteurized, must is thick with particulate matter, opaque, and comes in various shades of brown a

thumb|Sawdust made with hand saw thumb|:ja:オガ炭|Ogatan, Japanese [[charcoal briquettes made from sawdust]] thumb|Sawdust vendors in Kashgar markets

thumb|right|Bark chips applied as mulch A mulch is a layer of material applied to the surface of soil. Reasons for applying mulch include conservation of soil moisture, improving fertility and health of the soil, reducing weed growth, and enhancing the visual appeal of the area.

thumb|Wool fat tin (adeps lanae), at the Centre touristique de la Laine et de la Mode in Verviers, Belgium

300px|thumb|Rice chaff Chaff (; ) is dry, scale-like plant material such as the protective seed casings of cereal grains, the scale-like parts of flowers, or finely chopped straw. Chaff cannot be digested by humans, but it may be fed to livestock, ploughed into soil, or burned.

powder made from the grinding of wheat used for human consumption

good that is being purchased by or otherwise transferred to a second or later end user

flour made from dried and ground fish or parts of fish

thumb|Polycrystalline potash, with a penny (United States coin)|U.S. penny for reference. (The coin is in diameter and copper in color.)

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.

residue of coal combustion

thumb|Limescale build-up inside a pipe reduces both liquid flow through the pipe and thermal conduction from the liquid to the outer pipe shell. Both effects will reduce the pipe's overall thermal efficiency when used as a heat exchanger.

solid block remaining after pressing to extract liquids

thumb|right|250px|Pomace in a bladder press. These are [[Chardonnay grapes left over after pressing.]]

pile built of accumulated spoil

thumb|Driftwood on a pebble beach thumb|Driftwood on the beach in Sitges, Spain Driftwood is a wood that has been washed onto a shore or beach of a sea, lake, or river by the action of winds, tides or waves. It is part of beach wrack.

250px|right|thumb|Sambucus|Elder shoot cut longitudinally to show the broad, solid pith (rough textured, white) inside the wood (smooth, yellow tinged). Scale in millimeters. 250px|right|thumb|Walnut shoot cut longitudinally to show the chambered pith found in this genus. Scale in millimeters. Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which in some cases can store starch. In eudicotyledons, pith is located in the center of the stem. In monocotyledons, it extends only into roots. The pith is encircled by a ring of xylem; th

thumb|right|250px|Sugarcane bagasse in Hainan, China 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 materials. Agave bagasse is similar, but is the material remnants after extracting blue agave sap.

Ground mixture of bone and slaughterhouse waste products used as a fertilizer, and other uses

residue powder left after the combustion of wood

waste product from brewing coffee; used to adulterate pure coffee, to grow mushrooms, to stain wood, to freshen air, to make body soap scrubs, to treat wastewater, or to make biogas

thumb|Packaged leftovers from a Thanksgiving dinner

powder made from blood used as fertilizer and animal feed

thumb|right|Stover with some snow cover thumb|right|Stover (foreground), unharvested corn (background) Stover are the leaves and stalks of field crops, such as corn (maize), sorghum or soybean that are commonly left in a field after harvesting the grain. It is similar to straw, the residue left after any cereal grain or grass has been harvested at maturity for its seed. It can be directly grazed by cattle or dried for use as fodder. Stover has attracted some attention as a potential fuel source, and as biomass for fermentation or as a feedstock for cellulosic ethanol production. Stover from va

in chemistry, whatever remains or acts as a contaminant after a given class of events

right|thumb|A slurry composed of glass beads in silicone oil flowing down an inclined plane thumb|Potato starch slurry A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a centrifugal pump. The size of solid particles may vary from 1 micrometre up to hundreds of millimetres. The particles may settle below a certain transport velocity and the mixture can behave like a Newtonian or non-Newtonian fluid. Depending on the mi

type of animal product

Packing material

Cornmeal is a meal (coarse flour) ground from dried maize. It is a common staple food and is ground to coarse, medium, and fine consistencies, but it is not as fine as wheat flour can be. In Mexico and Louisiana, very finely ground cornmeal is referred to as corn flour. When fine cornmeal is made from maize that has been soaked in an alkaline solution, e.g., limewater (a process known as nixtamalization), it is called masa harina (or masa flour), which is used for making arepas, tamales, and tortillas. Boiled cornmeal is called polenta in Italy and is also a traditional dish and bread substitu

right|thumb|Husk of Corylus colurna|Corylus colurna (Turkish Hazel), containing 7 nuts In botany, a husk (or hull) 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 outer covering of a seed, fruit, or vegetable.

ground soybeans used for food

fine powdered form of coal, which is created by the crushing, grinding, or pulverizing of coal

brewing residue

pieces of glass that have been naturally weathered by water

deposits of residual yeast and other particles in wine-making

husk of rice grains

biodegradable waste

material formed from calcination of bones

the stalks, leaves, husks, roots, etc. left after crop is harvested and processed

reproductive part that germinates to grow into a plant

cereal residues from alcohol production

ground almonds

solid residue of combustion in the lower part of an industrial oven

poultry feather product

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 sugarcane can also be processed directly by ethanol fermentation. After the removal of the desired product (alcohol, ascorbic acid, etc.) the remaining material is called vinasse. Vinasse is sold after a partial dehydration and usually has a viscosity comparable to molasses. Commercially offered vinasse comes either from sugar cane and is called cane-vina

product of coal preparation