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 ...

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. Th ...

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 In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups (). The general molecular formula for dicarboxylic acids can be written as , where R can be aliphatic or aromatic. In general, dicarboxylic acids sho ...

. 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 con ...

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 used in baking, and Rochelle salt, commonly used in electroplating solutions.

As food additives

food additive Food additives are substances added to food to preserve Taste, flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), sal ...

s, tartrates are used as

antioxidant Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. This can lead to polymerization and other chain reactions. They are frequently added to industrial products, such as fuels and lubrica ...

s, acidity regulators, and emulsifiers. Examples include *sodium tartrates ( E335) ** monosodium tartrate ** sodium tartrate **

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 isot ...

the compound through which

Louis Pasteur Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization, the latter of which was named afte ...

discovered

chirality Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from ...

*potassium tartrates ( E336) ** potassium bitartrate (monopotassium tartrate, cream of tartar) ** potassium tartrate * potassium sodium tartrate ( E337) * calcium tartrate ( E354, used as

emulsifier An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Althoug ...

) *

stearyl tartrate Stearyl palmityl tartrate is a derivative of tartaric acid used as an emulsifier. It is produced by esterification of tartaric acid with commercial grade stearyl alcohol, which generally consists of a mixture of the fatty alcohols stearyl and ...

( E483, used as

)

In wine

wine Wine is an alcoholic drink typically made from Fermentation in winemaking, fermented grapes. Yeast in winemaking, Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different ...

, tartrates are the harmless crystalline deposits that separate from wines during

fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food p ...

and aging. The principal component of this deposit is potassium bitartrate, 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