Aeration (also called aerification or aeriation) is the

process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management * Business process, activities that produce a specific s ...

by which air is circulated through, mixed with or dissolved in a

liquid Liquid is a state of matter with a definite volume but no fixed shape. Liquids adapt to the shape of their container and are nearly incompressible, maintaining their volume even under pressure. The density of a liquid is usually close to th ...

or other substances that act as a

fluid In physics, a fluid is a liquid, gas, or other material that may continuously motion, move and Deformation (physics), deform (''flow'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are M ...

(such as soil). Aeration processes create additional surface area in the mixture, allowing greater chemical or suspension reactions.

Aeration of liquids

Methods

Aeration of liquids (usually water) is achieved by: * passing air through the liquid by means of the

Venturi tube The Venturi effect is the reduction in fluid pressure that results when a moving fluid speeds up as it flows from one section of a pipe to a smaller section. The Venturi effect is named after its discoverer, the Italian physicist Giovanni Bat ...

, aeration turbines or

compressed air Compressed air is air kept under a pressure that is greater than atmospheric pressure. Compressed air in vehicle tires and shock absorbers are commonly used for improved traction and reduced vibration. Compressed air is an important medium for t ...

which can be combined with diffuser(s) air stone(s), as well as fine bubble diffusers,

coarse bubble diffusers Coarse bubble diffusers are a pollution control technology used to aerate and or mix wastewater for sewage treatment. Description Coarse bubble diffusers produce 1/4 to 1/2 inch (6.4 to 13 mm) bubbles which rise rapidly from the floo ...

or linear aeration tubing. Ceramics are suitable for this purpose, often involving dispersion of fine air or gas bubbles through the porous ceramic into a liquid. The smaller the bubbles, the more gas is exposed to the liquid increasing the gas transfer efficiency. Diffusers or spargers can also be designed into the system to cause turbulence or mixing if desired. Porous ceramic diffusers are made by fusing aluminum oxide grains using porcelain bonds to form a strong, uniformly porous and homogeneous structure. The naturally hydrophilic material is easily wetted resulting in the production of fine, uniform bubbles. On a given volume of air or liquid, the

surface area The surface area (symbol ''A'') of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the d ...

changes proportionally with drop or bubble size, the very surface area where exchange can occur. Utilizing extremely small bubbles or drops increases the rate of gas transfer (aeration) due to the higher contact surface area. The pores which these bubbles pass through are generally micrometre-size.

Uses of aeration of liquids

* To smooth (

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) the flow of tap water at the faucet. * Production of aerated water or

cola Cola is a Carbonation, carbonated soft drink flavored with vanilla, cinnamon, citrus essential oil, oils, and other flavorings. Cola became popular worldwide after the American pharmacist John Stith Pemberton invented Coca-Cola, a trademarked br ...

for drinking purposes. * Secondary treatment of

sewage Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewerage, sewer system. Sewage consists of wastewater discharged fro ...

or industrial wastewater through use of aerating mixers/ diffusers. * To increase the

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

content of water used to house animals, such as aquarium fish or fish farm * To increase oxygen content of

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 Ethanol fermentation, fermented by the brewing yeast to prod ...

(unfermented beer) or

must Must is freshly crushed Juice, 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 ...

(unfermented wine) to allow yeast to propagate and begin

fermentation Fermentation is a type of anaerobic metabolism which harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic molecules, such as glucose or other sugars, are catabolized and reduce ...

. * To dispel other dissolved gases such as

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

. * In chemistry, to oxidise a compound dissolved or suspended in water. * To induce mixing of a body of otherwise still water. * Pond aeration.

Aeration of liquid solids

Aeration of soil

Aeration in food

Aeration in food is a process by which air is absorbed into the food item. Such processes produce lightness in cakes and bread by creating larger and more numerous pores. Chemicals and foodstuffs added to enhance this effect can be known as leavening agents. The color and texture of some sauces, pastes, and confections are also affected by air bubbles. One of the most frequent instances of such aeration in cooking is the whipping of

egg white Egg white is the clear liquid (also called the albumen or the glair/glaire) contained within an egg. In chickens, it is formed from the layers of secretions of the anterior section of the hen's oviduct during the passage of the egg. It forms a ...

to produce foam. Egg whites and other substances added to enhance similar aeration—such as the soy

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

gelatine Gelatin or gelatine () is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also be referred to as hydrolysis, hydrolyzed col ...

added to American nougat in candy bars—are known as whipping agents or aerating agents.

Aeration in beverages

In wine tasting, a variety of methods are used to aerate the wine and bring out the aromas, including swirling wine in the glass, using a decanter to increase exposure to air, or using a specialized wine aerator. Cider from

Asturias Asturias (; ; ) officially the Principality of Asturias, is an autonomous communities of Spain, autonomous community in northwest Spain. It is coextensive with the provinces of Spain, province of Asturias and contains some of the territory t ...

is poured into the glass from a height of about 1 metre (''el escanciado'') to increase aeration.

References

{{reflist, 2 Chemical processes Gas technologies