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Potassium bitartrate

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– Potassium bitartrate first characterized by Swedish chemist Carl Wilhelm Scheele
– Use of potassium bitartrate reported to date back 7000 years to ancient village in northern Iran
– Modern applications of cream of tartar started in 1768 in French cuisine
– Connection between potassium bitartrate and grape toxicity in pets first proposed in 2021
– Deemed likely source of grape and raisin toxicity to pets

– Naturally formed in grapes from acid dissociation of tartaric acid
– Low solubility in water, crystallizes in wine casks during grape juice fermentation
– Precipitates out of wine in bottles, forms wine diamonds
– Crystals often found on underside of cork in wine-filled bottles stored below 10°C
– Less prevalent in red wines due to higher tannin and sugar content

**Applications in Food and Baking:**
– Stabilizes egg whites, whipped cream
– Anti-caking, thickening agent
– Prevents sugar syrups crystallization
– Reduces discoloration of boiled vegetables
– Used in baking powder, salt substitutes
– Adds volume and tenderness to cakes
– Lowers pH for optimal foaming properties in egg whites
– Results in whiter crumb due to pH changes
– Prevents sugar crystallization in invert syrups
– Crucial component in baking powder for leavening

**Household and Traditional Uses:**
– Mixed with acidic liquid for metal cleaning
– Can be used with water for cleaning porcelain stains
– Mistakenly mixed with vinegar and baking soda
– Creates paste-like cleaning agent for metals
– Used for removing light stains from porcelain
– Adjusts solubility and hydrolysis of mordant salts in traditional dyeing
– Cleans rust from hand tools when mixed with hydrogen peroxide
– Slows the set time of plaster of Paris products
Cream of tartar is the active ingredient in commercial retardant premix additives

**Other Applications:**
– Activates henna for hair dyeing in cosmetics
– Used as a purgative in medicinal practices
– Excessive use may lead to hyperkalemia
– Primary pH buffer reference standard in chemistry
– Saturated solution of potassium bitartrate has a pH of 3.557 at 25°C
– Dissociates into acid tartrate, tartrate, and potassium ions in water
– Burning cream of tartar produces potassium carbonate (pearl ash)

Potassium bitartrate, also known as potassium hydrogen tartrate, with formula KC4H5O6, is a chemical compound with a number of uses.

Potassium bitartrate
Potassium bitartrate
Preferred IUPAC name
  • Potassium (2R,3R)-2,3,4-trihydroxy-4-oxobutanoate
Other names
  • Potassium hydrogen tartrate
  • Cream of tartar
  • Potassium acid tartrate
  • Monopotassium tartrate
  • Beeswing
3D model (JSmol)
ECHA InfoCard 100.011.609 Edit this at Wikidata
E number E336 (antioxidants, ...)
  • 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
  • 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
  • [C@@H]([C@H](C(=O)[O-])O)(C(=O)O)O.[K+]
Molar mass 188.177
Appearance White crystalline powder
Density 1.05 g/cm3 (solid)
  • 0.57 g/100 ml (20 °C)
  • 6.1 g/100 ml (100 °C)
Solubility Soluble in acid, alkali
Insoluble in acetic acid, alcohol
A12BA03 (WHO)
Lethal dose or concentration (LD, LC):
22 g/kg (oral, rat)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Some of the uses of potassium bitartrate (cream of tartar) include as a mordant in textile dyeing, in the galvanic tinning of metals, as reducer of chromium trioxide in mordants for wool, in dusting powders for gloves, to make hard candies, in baking powders and baking mixes, as a metal processing agent (prevents oxidation), as an intermediate for other potassium tartrates, to remove sulfur dioxide from waste gases (in solution), as a medical cathartic, as a diuretic, and as a historic veterinary laxative and diuretic.

It 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 acid). The resulting powder can be used in baking or as a cleaning solution (when mixed with an acidic solution such as lemon juice or white vinegar).

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