Cream of tartar

Potassium bitartrate

Names
Other names potassium hydrogen tartrate cream of tartar potassium acid tartrate monopotassium tartrate potassium;(2R,3R)-2,3,4-trihydroxy-4-oxobutanoate
Identifiers
CAS Number	868-14-4 Y
3D model (Jmol)	Interactive image
ChemSpider	12783 N
ECHA InfoCard	100.011.609
PubChem	13352
InChI InChI=1S/C4H6O6.K/c5-1(3(7)8)2(6)4(9)10;/h1-2,5-6H,(H,7,8)(H,9,10);/q;+1/p-1/t1-,2-;/m1./s1 N Key: KYKNRZGSIGMXFH-ZVGUSBNCSA-M N InChI=1/C4H6O6.K/c5-1(3(7)8)2(6)4(9)10;/h1-2,5-6H,(H,7,8)(H,9,10);/q;+1/p-1/t1-,2-;/m1./s1 Key: KYKNRZGSIGMXFH-APGVQJISBP
SMILES [C@@H]([C@H](C(=O)[O-])O)(C(=O)O)O.[K+]
Properties
Chemical formula	KC4H5O6
Molar mass	188.177
Appearance	white crystalline powder
Density	1.05 g/cm3 (solid)
Solubility in water	0.37 g/100mL (20 °C) 6.1 g/100mL (100 °C)
Solubility	soluble in acid, alkali insoluble in acetic acid, alcohol
Refractive index (nD)	1.511
Pharmacology
ATC code	A12BA03 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Potassium bitartrate, also known as potassium hydrogen tartrate, with formula KC₄H₅O₆, is a byproduct of winemaking. In cooking it is known as cream of tartar. It is the potassium acid salt of tartaric acid (a carboxylic acid). It can be used in baking or as a cleaning solution (when mixed with an acidic solution such as lemon juice or white vinegar).

Potassium bitartrate crystallizes in wine casks during the fermentation of grape juice, and can precipitate out of wine in bottles. The crystals (wine diamonds) will often form on the underside of a cork in wine-filled bottles that have been stored at temperatures below 10 °C (50 °F), and will seldom, if ever, dissolve naturally into the wine.

These crystals also precipitate out of fresh grape juice that has been chilled or allowed to stand for some time. To prevent crystals forming in homemade grape jam or jelly, the prerequisite fresh grape juice should be chilled overnight to promote crystallization. The potassium bitartrate crystals are removed by filtering through two layers of cheesecloth. The filtered juice may then be made into jam or jelly. In some cases they adhere to the side of the chilled container, making filtering unnecessary.

The crude form (known as beeswing) is collected and purified to produce the white, odorless, acidic powder used for many culinary and other household purposes.

In food, potassium bitartrate is used for:

Additionally it is used as a component of:

A similar acid salt, sodium acid pyrophosphate, can be confused with cream of tartar because of their common function as a component of baking powder.