A tartrate is a

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...

of the

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

tartaric acid Tartaric acid is a white, crystalline organic acid that occurs naturally in many fruits, most notably in grapes, but also in bananas, tamarinds, and citrus. Its salt, potassium bitartrate, commonly known as cream of tartar, develops naturally ...

, a dicarboxylic acid. The formula of the tartrate

dianion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...

is O⁻OC-CH(OH)-CH(OH)-COO⁻ or C₄H₄O₆²⁻. The main forms of tartrates used commercially are pure crystalline tartaric acid used as an

acidulant Acidulants are chemical compounds that give a tart, sour, or acidic flavor to foods or enhance the perceived sweetness of foods. Acidulants can also function as leavening agents and emulsifiers in some kinds of processed foods.Berry, S.K.. (2001). R ...

in non-alcoholic drinks and foods,

cream of tartar Potassium bitartrate, also known as potassium hydrogen tartrate, with formula K C4 H5 O6, is a byproduct of winemaking. In cooking, it is known as cream of tartar. It is processed from the potassium acid salt of tartaric acid (a carboxylic ac ...

used in baking, and

Rochelle salt Potassium sodium tartrate tetrahydrate, also known as Rochelle salt, is a double salt of tartaric acid first prepared (in about 1675) by an apothecary, Pierre Seignette, of La Rochelle, France. Potassium sodium tartrate and monopotassium phospha ...

, commonly used in electroplating solutions.

As food additives

As food additives, tartrates are used as antioxidants, acidity regulators, and emulsifiers. Examples include *sodium tartrates ( E335) **

monosodium tartrate Monosodium tartrate or sodium bitartrate is a sodium acid salt of tartaric acid. As a food additive it is used as an acidity regulator and is known by the E number E335. As an analytical reagent, it can be used in a test for ammonium cation which ...

sodium tartrate Sodium tartrate (Na2C4H4O6) is a salt used as an emulsifier and a binding agent in food products such as jellies, margarine, and sausage casings. As a food additive, it is known by the E number E335. Because its crystal structure captures a ve ...

sodium ammonium tartrate Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable is ...

the compound through which Louis Pasteur discovered chirality *potassium tartrates ( E336) **

potassium bitartrate Potassium bitartrate, also known as potassium hydrogen tartrate, with formula K C4 H5 O6, is a byproduct of winemaking. In cooking, it is known as cream of tartar. It is processed from the potassium acid salt of tartaric acid (a carboxylic ac ...

(monopotassium tartrate, cream of tartar) **

potassium tartrate Potassium tartrate, dipotassium tartrate or argol has formula K2C4H4O6. It is the potassium salt of tartaric acid. It is often confused with potassium bitartrate, also known as cream of tartar. As a food additive, it shares the E number E336 ...

potassium sodium tartrate Potassium sodium tartrate tetrahydrate, also known as Rochelle salt, is a double salt of tartaric acid first prepared (in about 1675) by an apothecary, Pierre Seignette, of La Rochelle, France. Potassium sodium tartrate and monopotassium phospha ...

( E337) *

calcium tartrate Calcium tartrate, exactly calcium L-tartrate, is a byproduct of the wine industry, prepared from wine fermentation dregs. It is the calcium salt of L-tartaric acid, an acid most commonly found in grapes. Its solubility decreases with lower temper ...

( E354, used as emulsifier) * stearyl tartrate ( E483, used as emulsifier)

In wine

wine Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are m ...

, tartrates are the harmless crystalline deposits that separate from wines during fermentation and aging. The principal component of this deposit is

, a potassium salt of tartaric acid. Small amounts of pulp debris, dead yeast, and precipitated phenolic materials such as

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

s make up the impurities contaminating the potassium acid tartrate. The wine industry is the only source of commercial tartrates, and the crystalline encrustations left inside fermentation vessels are regularly scraped off and purified for commercial use. Tartrates separate from new wines because they are less soluble in alcohol than in non-alcoholic grape juice. The exact figures vary according to variety and region, but approximately half of the tartrate soluble in grape juice is insoluble in wine. The problem is that the tartrate may remain in a supersaturated state after bottling, only to crystallize at some unpredictable later time. Tartrates precipitated in red wine usually take on some red pigment and are commonly dismissed as mere sediment; in white wines they can look alarmingly like shards of glass. The modern wine industry has decided that tartrate stabilization is preferable to consumer education.{{cite book, last=Robinson, first=Janis, title=The Oxford Companion to Wine, year=2006, publisher=Oxford University Press, isbn=0198609906, page
681–682
url=https://archive.org/details/oxfordcompaniont00janc/page/681, url-access=registration

As concrete admixture

Tartrate is also used as a retarder to delay the setting time of

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

when temperature is too high.

References

Concrete admixtures