View source for Potassium bitartrate

{{Short description|Chemical salt used in cooking as cream of tartar}}
{{Redirect|Cream of tartar|the sauce|Tartar sauce}}
{{Use dmy dates|date=October 2020}}
{{chembox
| Verifiedfields = changed
| Watchedfields  = changed
| verifiedrevid  = 444344256
| Name           = Potassium bitartrate
| ImageFile      = Potassium-bitartrate-2D-skeletal.svg
| ImageFileL1    = Potassium-3D.png
| ImageFileR1    = Bitartrate-ion-3D-balls.png
| ImageName      = Potassium bitartrate
| PIN            = {{ubli|Potassium (2''R'',3''R'')-2,3,4-trihydroxy-4-oxobutanoate}}
| OtherNames     = {{ubli
 | Potassium hydrogen tartrate
 | Cream of tartar
 | Potassium acid tartrate
 | Monopotassium tartrate
 | Beeswing
 }}
| Section1       = {{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 868-14-4
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = NPT6P8P3UU
| PubChem = 23666342
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| ChemSpiderID = 12783
| SMILES = [C@@H]([C@H](C(=O)[O-])O)(C(=O)O)O.[K+]
| 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
| InChIKey = KYKNRZGSIGMXFH-APGVQJISBP
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 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
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = KYKNRZGSIGMXFH-ZVGUSBNCSA-M
  }}
| Section2       = {{Chembox Properties
| Formula      = KC<sub>4</sub>H<sub>5</sub>O<sub>6</sub>
| MolarMass    = 188.177
| Appearance   = White crystalline powder
| Density      = 1.05&nbsp;g/cm<sup>3</sup> (solid)
| Solubility   = {{ubli
 | 0.57&nbsp;g/100&thinsp;ml (20&nbsp;°C)
 | 6.1&nbsp;g/100&thinsp;ml (100&nbsp;°C)
 }}
| SolubleOther = Soluble in acid, alkali <br>Insoluble in [[acetic acid]], [[ethanol|alcohol]]
| RefractIndex = 1.511
}}
| Section3       = 
| Section4       = 
| Section5       = 
| Section6       = {{Chembox Pharmacology
| ATCCode_prefix = A12
| ATCCode_suffix = BA03
}}
| Section7       = {{Chembox Hazards
| NFPA-S =
| LD50   = 22&nbsp;g/kg (oral, rat)
}}
}}

'''Potassium bitartrate''', also known as '''potassium hydrogen tartrate''', with formula [[potassium|K]][[Carbon|C<sub>4</sub>]][[hydrogen|H<sub>5</sub>]][[oxygen|O<sub>6</sub>]], is the [[potassium]] [[acid salt]] of [[tartaric acid]] (a [[carboxylic acid]])—specifically, l-(&nbsp;+&nbsp;)-tartaric acid.<ref name=":5">{{Cite web |website=PubChem |title=Potassium acid tartrate |url=https://pubchem.ncbi.nlm.nih.gov/compound/23681127 |access-date=2022-08-18 |publisher=National Center for Biotechnology Information |language=en}}</ref> Especially in cooking, it is also known as '''cream of tartar'''. Tartaric acid and potassium naturally occur in grapes, its crude [[Precipitation (chemistry)|precipitate]] form '''tartar''' or '''wine stone''' are byproducts of [[winemaking]] found deposited on top of [[must]] barrels which can be purified.<ref>{{cite book |last=Rösslin |first=Eucharius (the Younger)|editor-last1=Belkin |editor-first1=Johanna Schwind |editor-last2=Caley |editor-first2=Earle Radcliffe |title=On minerals and mineral products: chapters on minerals from his « Kreutterbuch » |date=1978 |publisher=W. de Gruyter |location=Berlin |isbn=3-11-006907-5 |pages=315-6}}</ref>

Approved by the FDA as a direct food substance, cream of tartar is used as an additive, stabilizer, pH control agent, antimicrobial agent, processing aid, and thickener in various food products. It is used as a component of [[baking powder]]s and baking mixes, and is valued for its role in stabilizing egg whites, which enhances the volume and texture of [[Meringue|meringues]] and [[Soufflé|soufflés]]. Its acidic properties prevent sugar syrups from crystallizing, aiding in the production of smooth confections such as candies and frostings. When combined with [[sodium bicarbonate]], it acts as a [[leavening agent]], producing [[carbon dioxide]] gas that helps baked goods rise. It will also stabilize [[whipped cream]], allowing it to retain its shape for longer periods.

Potassium bitartrate further serves as [[mordant]] in textile dyeing, as reducer of [[chromium trioxide]] in mordants for wool, as a metal processing agent that prevents oxidation, as an intermediate for other potassium [[tartrate]]s, as a cleaning agent when mixed with a weak acid such as [[vinegar]], and as reference standard [[Buffer solution|pH buffer]]. It has a long history of medical and veterinary use as a laxative administered as a rectal suppository, and is used also as a [[cathartic]] and as a [[diuretic]].<ref>{{Cite web |last=PubChem |title=Potassium bitartrate |url=https://pubchem.ncbi.nlm.nih.gov/compound/23666342 |access-date=2023-11-02 |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref> It is an approved third-class [[Over-the-counter drug|OTC drug]] in Japan{{cn|date=June 2025}} and was one of active ingredients in Phexxi, a non-hormonal contraceptive agent that was approved by the FDA in May 2020.<ref>{{Cite web |title=Phexxi (lactic acid, citric acid and potassium bitartrate) FDA Approval History |url=https://www.drugs.com/history/phexxi.html |access-date=2022-06-18 |website=Drugs.com |language=en}}</ref>

== History ==
Potassium bitartrate was first characterized by Swedish chemist [[Carl Wilhelm Scheele]] (1742–1786).<ref>{{Cite web |title=Karl Wilhelm Scheele, Swedish chemist (1742-86) |url=https://www.1902encyclopedia.com/S/SCH/karl-wilhelm-scheele.html |access-date=2022-12-05 |website=www.1902encyclopedia.com}}</ref> This was a result of Scheele's work studying [[fluorite]] and [[hydrofluoric acid]].<ref>{{Citation |last=Lennartson |first=Anders |title=The Chemical Works of Carl Wilhelm Scheele |series=SpringerBriefs in Molecular Science |date=2017 |url=https://doi.org/10.1007/978-3-319-58181-1 |editor-last=Lennartson |editor-first=Anders |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-58181-1 |isbn=978-3-319-58181-1 |access-date=2022-12-05|url-access=subscription }}</ref>

Scheele may have been the first scientist to publish work on potassium bitartrate, but use of potassium bitartrate has been reported to date back 7000 years to an ancient village in northern Iran.<ref name=":4">{{Cite web |date=2012-12-19 |title=Cream Of Tartar: What Is It, Anyway? |url=https://www.huffpost.com/entry/cream-of-tar-tar_n_2322569 |access-date=2022-12-05 |website=HuffPost |language=en}}</ref> Modern applications of cream of tartar started in 1768 after it gained popularity when the French started using it regularly in their cuisine.<ref name=":4" />

In 2021, a connection between potassium bitartrate and canine and feline toxicity of grapes was first proposed.<ref>{{cite journal |last1=Wegenast |first1=Colette |last2=Meadows |first2=Irina |last3=Anderson |first3=Rachele |last4=Southard |first4=Teresa |title=Letters: Unique sensitivity of dogs to tartaric acid and implications for toxicity of grapes |journal=Journal of the American Veterinary Medical Association |date=1 April 2021 |volume=258 |issue=7 |pages=706–707 |doi=10.2460/javma.258.7.704 |pmid=33754816 |url=https://avmajournals.avma.org/view/journals/javma/258/7/javma.258.7.704.xml |access-date=29 January 2024|url-access=subscription }}</ref>  Since then, it has been deemed likely as the source of grape and raisin toxicity to pets.<ref>{{cite journal |last1=Wegenast |first1=Colette |last2=Meadows |first2=Irina |last3=Anderson |first3=Rachele |last4=Southard |first4=Teresa |last5=González Barrientos |first5=Cristy |last6=Wismer |first6=Tina |title=Acute kidney injury in dogs following ingestion of cream of tartar and tamarinds and the connection to tartaric acid as the proposed toxic principle in grapes and raisins |journal=Journal of Veterinary Emergency and Critical Care |date=23 July 2022 |volume=32 |issue=6 |pages=812–816 |doi=10.1111/vec.13234 |pmid=35869755 |url=https://onlinelibrary.wiley.com/doi/10.1111/vec.13234 |access-date=29 January 2024|url-access=subscription }}</ref>

==Occurrence==
[[File:Bitartrato de potasio 01.JPG|thumb|Potassium bitartrate in an empty white wine bottle]]
Potassium bitartrate is naturally formed in grapes from the acid dissociation of tartaric acid into bitartrate and tartrate ions.<ref name=":1">{{Cite journal |last1=Coulter |first1=A.D. |last2=Holdstock |first2=M.G. |last3=Cowey |first3=G.D. |last4=Simos |first4=C.A. |last5=Smith |first5=P.A. |last6=Wilkes |first6=E.N. |date=2015 |title=Potassium bitartrate crystallisation in wine and its inhibition: Cold stability |journal=Australian Journal of Grape and Wine Research |language=en |volume=21 |pages=627–641 |doi=10.1111/ajgw.12194|doi-access=free }}</ref>

Potassium bitartrate has a low solubility in water. It [[crystal]]lizes in wine casks during the [[fermentation (food)|fermentation]] of [[grape]] [[juice]], and can precipitate out of wine in bottles. The rate of potassium bitartrate precipitation depends on the rates of nuclei formation and [[crystal growth]], which varies based on a wine's alcohol, sugar, and extract content.<ref name=":0">{{Cite journal |last1=Marsh |first1=G. L. |last2=Joslyn |first2=M. A. |date=1935 |title=Precipitation Rate of Cream of Tartar from Wine Effect of Temperature |url=https://pubs.acs.org/doi/abs/10.1021/ie50311a007 |journal=Industrial & Engineering Chemistry |language=en |volume=27 |issue=11 |pages=1252–1257 |doi=10.1021/ie50311a007 |issn=0019-7866|url-access=subscription }}</ref> The crystals ([[Wine Diamonds|wine diamonds]]) will often form on the underside of a cork in wine-filled bottles that have been stored at temperatures below {{convert|10|°C}}, and will seldom, if ever, dissolve naturally into the wine. Over time, crystal formation is less likely to occur due to the decreasing [[supersaturation]] of potassium bitartrate, with the greatest amount of precipitation occurring in the initial few days of cooling.<ref name=":0" />

Historically, it was known as '''beeswing''' for its resemblance to the sheen of bees' wings. It was collected and purified to produce the white, odorless, [[acidic]] powder used for many culinary and other household purposes.

These crystals also precipitate out of fresh grape juice that has been chilled or allowed to stand for some time.<ref>{{cite web |author=Max Williams at McNicol Williams Management & Marketing Services |url=http://www.lloydsvineyard.com.au/faqs.php |title=Lloyds Vineyard FAQs |publisher=Lloydsvineyard.com.au |access-date=2018-04-19 |archive-url=https://web.archive.org/web/20111215030948/http://www.lloydsvineyard.com.au/faqs.php |archive-date=15 December 2011 |url-status=dead }}</ref> To prevent crystals from forming in homemade grape [[Fruit preserves|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.<ref>{{cite web|url=http://www.uga.edu/nchfp/how/can_07/grape_jelly_powder.html |title=National Center for Home Food Preservation |publisher=Uga.edu |access-date=2018-04-19}}</ref> In some cases they adhere to the side of the chilled container, making filtering unnecessary.

The presence of crystals is less prevalent in red wines than in white wines. This is because red wines have a higher amount of [[tannin]] and colouring matter present as well as a higher sugar and extract content than white wines.<ref name=":0" /> Various methods such as promoting crystallization and filtering, removing the active species required for potassium bitartrate precipitation, and adding additives have been implemented to reduce the presence of potassium bitartrate crystals in wine.<ref name=":1" />

==Applications==

===In food===
{{Cookbook|Cream of Tartar}}[[File:Folgers Cream Tartar etc.jpg|thumb|Folger's Golden Gate Cream Tartar, first half of 20th century]]
In food, potassium bitartrate is used for:
* Stabilizing [[egg white]]s, increasing their warmth-tolerance and volume<ref name="science">{{cite book |title=The science of good cooking : master 50 simple concepts to enjoy a lifetime of success in the kitchen |date=2012 |publisher=America's Test Kitchen |isbn=978-1-933615-98-1 |page=199 |edition=1st}}</ref>
* Stabilizing [[whipped cream]], maintaining its texture and volume<ref>{{cite web |title=How to Use Cream of Tartar |url=https://www.wikihow.com/Use-Cream-of-Tartar |website=wikiHow |access-date=28 May 2019 |archive-date=28 May 2019 |archive-url=https://web.archive.org/web/20190528110909/https://www.wikihow.com/Use-Cream-of-Tartar |url-status=dead }}</ref>
* [[Anti-caking agent|Anti-caking]] and [[Thickening agent|thickening]]<ref>{{cite web |last1=Stephens |first1=Emily |title=The Incredible Cream of Tartar – How to Use and What to Substitute With |url=https://www.mygreatrecipes.com/blog/incredible-cream-tartar-use-substitute/ |website=MyGreatRecipes |access-date=28 May 2019  |date=18 February 2017}}</ref>
* Preventing [[sugar syrup]]s from [[Crystallization|crystallizing]] by causing some of the [[sucrose]] to break down into [[glucose]] and [[fructose]]<ref name="Provost">{{cite book |last1=Provost |first1=Joseph J. |last2=Colabroy |first2=Keri L. |last3=Kelly |first3=Brenda S. |last4=Wallert |first4=Mark A. |title=The Science of Cooking : Understanding the Biology and Chemistry Behind Food and Cooking |date=2016 |publisher=John Wiley and Sons, Inc. |isbn=9781118674208 |page=504 |url=https://books.google.com/books?id=9ydECwAAQBAJ&pg=PA503}}</ref>
* Reducing discoloration of boiled [[vegetable]]s

Additionally, it is used as a component of:
* [[Baking powder]], as an acid ingredient to activate [[baking soda]]<ref>{{cite book |last1=McGee |first1=Harold |title=On food and cooking : the science and lore of the kitchen |date=2004 |publisher=Scribner |isbn=978-0-684-80001-1 |page=533,534 |edition=2nd}}</ref>
* [[Salt substitute|Salt substitutes]], in combination with [[potassium chloride]]

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

=== Baking ===
Adding cream of tartar to egg whites gives volume to cakes, and makes them more tender.<ref name=":3">{{Cite journal |last1=Oldham |first1=A. M. |last2=Mccomber |first2=D. R. |last3=Cox |first3=D. F. |date=2000-12-01 |title=Effect of Cream of Tartar Level and Egg White Temperature on Angel Food Cake Quality |url=http://doi.wiley.com/10.1177/1077727X00292003 |journal=Family and Consumer Sciences Research Journal |language=en |volume=29 |issue=2 |pages=111–124 |doi=10.1177/1077727X00292003 |issn=1077-727X|url-access=subscription }}</ref> As cream of tartar is added, the pH decreases to around the isoelectric point of the foaming proteins in egg whites. Foaming properties of egg whites are optimal at this pH due to increased protein-protein interactions.<ref>{{Cite journal |last1=Waniska |first1=R. D. |last2=Kinsella |first2=J. E. |title=Foaming Properties of Proteins: Evaluation of a Column Aeration Apparatus Using Ovalbumin |date=1979 |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2621.1979.tb06447.x |journal=Journal of Food Science |language=en |volume=44 |issue=5 |pages=1398–1402 |doi=10.1111/j.1365-2621.1979.tb06447.x |issn=0022-1147|url-access=subscription }}</ref> The low pH also results in a whiter crumb in cakes due to flour pigments that respond to these pH changes.<ref name=":3" /> However, adding too much cream of tartar (>2.4% weight of egg white) can affect the texture and taste of cakes.<ref name=":3" /> The optimal cream of tartar concentration to increase volume and the whiteness of interior crumbs without making the cake too tender, is about 1/4 tsp per egg white.<ref name=":3" />

As an acid, cream of tartar with heat reduces sugar crystallization in [[Inverted sugar syrup|invert syrups]] by helping to break down [[sucrose]] into its monomer components - [[fructose]] and [[glucose]] in equal parts.<ref name=":2">{{Cite book |last=Figoni |first=Paula |title=How Baking Works: Exploring the Fundamentals of Baking Science |publisher=JOHN WILEY & SONS, INC |year=2007 |isbn=9780471747239 |edition=2nd}}</ref> Preventing the formation of sugar crystals makes the syrup have a non-grainy texture, shinier and less prone to break and dry. However, a downside of relying on cream of tartar to thin out crystalline sugar confections (like fudge) is that it can be hard to add the right amount of acid to get the desired consistency.

Cream of tartar is used as a type of [[acid salt]] that is crucial in [[baking powder]].<ref name=":2" /> Upon dissolving in batter or dough, the [[tartaric acid]] that is released reacts with [[Sodium bicarbonate|baking soda]] to form [[carbon dioxide]] that is used for [[Leavening agent|leavening]]. Since cream of tartar is fast-acting, it releases over 70 percent of carbon dioxide gas during mixing.

=== Household use ===
[[File:Potassium hydrogen tartrate (1).JPG|thumb|Potassium bitartrate powder]]
Potassium bitartrate can be mixed with an acidic liquid, such as lemon juice or white vinegar, to make a paste-like cleaning agent for metals, such as [[brass]], [[aluminium]], or [[copper]], or with water for other cleaning applications, such as removing light stains from [[porcelain]].<ref>{{cite web|url=http://www.msue.msu.edu/objects/content_revision/download.cfm/revision_id.499694/workspace_id.-4/01500631.html/ |archive-url=https://web.archive.org/web/20090623085023/http://www.msue.msu.edu/objects/content_revision/download.cfm/revision_id.499694/workspace_id.-4/01500631.html/ |url-status=dead |archive-date=2009-06-23 |title=Michigan State University Extension Home Maintenance And Repair – Homemade Cleaners – 01500631, 06/24/03 |access-date=2018-04-19}}</ref>
This mixture is sometimes mistakenly made with vinegar and [[sodium bicarbonate]] (baking soda), which actually [[Acid–base reaction|react]] to [[Neutralization (chemistry)|neutralize]] each other, creating [[carbon dioxide]] and a [[sodium acetate]] solution.

Cream of tartar was often used in traditional [[dyeing]] where the [[complexing]] action of the tartrate ions was used to adjust the solubility and [[hydrolysis]] of [[mordant]] salts such as [[Tin(II) chloride|tin chloride]] and [[alum]].

Cream of tartar, when mixed into a paste with [[hydrogen peroxide]], can be used to clean [[rust]] from some [[hand tool]]s, notably hand [[File (tool)|files]]. The paste is applied, left to set for a few hours, and then washed off with a baking soda/water solution. After another rinse with water and thorough drying, a thin application of oil will protect the file from further rusting.

Slowing the set time of [[Plaster|plaster of Paris]] products (most widely used in [[gypsum plaster]] wall work and artwork casting) is typically achieved by the simple introduction of almost any acid diluted into the mixing water. A commercial retardant premix additive sold by USG to trade interior plasterers includes at least 40% potassium bitartrate. The remaining ingredients are the same plaster of Paris and [[quartz]]-silica [[Construction aggregate|aggregate]] already prominent in the main product. This means that the only active ingredient is the cream of tartar.<ref>{{cite web|title=Material Safety Data Sheet: Gypsum Plaster Retarder for Lime-Based Products|url=https://www.usg.com/content/dam/USG_Marketing_Communications/canada/product_promotional_materials/finished_assets/gypsum-plaster-retarder-lime-based-products-en-can-53100112.pdf|publisher=USG Inc.|access-date=21 July 2016|archive-url=https://web.archive.org/web/20160829063803/https://www.usg.com/content/dam/USG_Marketing_Communications/canada/product_promotional_materials/finished_assets/gypsum-plaster-retarder-lime-based-products-en-can-53100112.pdf|archive-date=29 August 2016|url-status=dead}}</ref>

===Cosmetics===
For dyeing hair, potassium bitartrate can be mixed with [[henna]] as the mild acid needed to activate the henna.

=== Textiles ===
Cream of tartar is often used in traditional dyeing prcesses, where its complexing action helps fix mordant salts like [[Tin(II) chloride|tin chloride]] and [[alum]] to fabric. It is especially useful in brightening [[Carmine|cochineal dye]].<ref name=":6">{{Cite web |title=Potassium Bitartrate {{!}} 868-14-4 |url=https://www.chemicalbook.com/ChemicalProductProperty_EN_CB7854493.htm |access-date=2025-12-23 |website=ChemicalBook |language=en}}</ref><ref>{{Cite web |title=Guide to Natural Dyes |url=https://naturaldyes.ca/instructions |access-date=2025-12-23 |website=Natural Dyes |language=en-US}}</ref>

===Medicinal use===
Cream of tartar has been used internally as a [[purgative]], but this is dangerous because an excess of potassium, or [[hyperkalemia]], may occur.<ref>{{cite journal | journal = [[Journal of Medical Toxicology]] | date = 2013 | volume = 9 | issue = 1 | pages = 79–81 | doi = 10.1007/s13181-012-0255-x | pmc = 3570668 | pmid=22926733 | title = Life-Threatening Hyperkalemia from Cream of Tartar Ingestion | first1 = Daniel E. | last1 = Rusyniak | first2 = Pamela J. | last2 = Durant | first3 = James B. | last3 = Mowry | first4 = Jo A. | last4 = Johnson | first5 = Jayne A. | last5 = Sanftleben | first6 = Joanne M. | last6 = Smith}}</ref><ref>{{Cite journal |last1=Rusyniak |first1=Daniel E. |last2=Durant |first2=Pamela J. |last3=Mowry |first3=James B. |last4=Johnson |first4=Jo A. |last5=Sanftleben |first5=Jayne A. |last6=Smith |first6=Joanne M. |date=March 2013 |title=Life-threatening hyperkalemia from cream of tartar ingestion |journal=Journal of Medical Toxicology|volume=9 |issue=1 |pages=79–81 |doi=10.1007/s13181-012-0255-x |issn=1937-6995 |pmc=3570668 |pmid=22926733}}</ref>

Potassium bitartrate is also used as a laxative. The carbon dioxide it releases causes mechanical distension against the intestinal wall, inducing bowel movements. Combined with sodium bicarbonate in a poly(ethylene glycol)-based suppository, it is a useful and safe treatment for patients at risk of electrolyte, renal, or cardiovascular disorders.<ref>{{Cite web |title=Potassium bitartrate |url=https://go.drugbank.com/drugs/DB11107 |access-date=2025-12-23 |website=go.drugbank.com |language=en}}</ref> It is a third-class over-the-counter drug in Japan.<ref name=":5" />

===Chemistry===
Potassium bitartrate is the United States' [[National Institute of Standards and Technology]]'s primary reference standard for a [[Buffer solution|pH buffer]].  Using an excess of the salt in water, a [[saturated solution]] is created with a [[pH]] of 3.557 at {{convert|25|°C}}. Upon dissolution in water, potassium bitartrate will [[dissociate]] into acid tartrate, tartrate, and potassium [[ions]]. Thus, a saturated solution creates a buffer with standard pH. Before use as a standard, it is recommended that the solution be filtered or [[Decantation|decanted]] between {{convert|22|°C}} and {{convert|28|°C}}.<ref>{{citation|last=Harris|first=Daniel C.|title=Quantitative Chemical Analysis|edition=7th|publisher=[[W. H. Freeman]]|place=New York|date=17 July 2006|isbn=978-0-7167-7694-9}}</ref>

[[Potassium carbonate]] can be made by burning cream of tartar, which produces "[[potash]]" This process is now obsolete but produced a higher quality (reasonable purity) than "[[potash]]" extracted from wood or other plant ashes.

== Production ==
Potassium bitartrate is often produced as a by-product of [[winemaking]]. Lees (sediment) are collected following the fermentation process and dissolved in hot water, filtered, and cooled.<ref name=":7">{{Cite journal |last1=Kontogiannopoulos |first1=Konstantinos N. |last2=Patsios |first2=Sotiris I. |last3=Karabelas |first3=Anastasios J. |date=2016-06-13 |title=Tartaric acid recovery from winery lees using cation exchange resin: Optimization by Response Surface Methodology |url=https://www.sciencedirect.com/science/article/abs/pii/S1383586616301459 |journal=Separation and Purification Technology |volume=165 |pages=32–41 |doi=10.1016/j.seppur.2016.03.040 |issn=1383-5866|url-access=subscription }}</ref> Occasionally, excess [[tartaric acid]] is added to the lees to increase the saturation of potassium bitartrate in solution.<ref>{{Cite journal |last=Coulter |first=A.d. |last2=Holdstock |first2=M.g. |last3=Cowey |first3=G.d. |last4=Simos |first4=C.a. |last5=Smith |first5=P.a. |last6=Wilkes |first6=E.n. |date=2015 |title=Potassium bitartrate crystallisation in wine and its inhibition |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/ajgw.12194 |journal=Australian Journal of Grape and Wine Research |language=en |volume=21 |issue=S1 |pages=627–641 |doi=10.1111/ajgw.12194 |issn=1755-0238}}</ref> Since the solubility of potassium bitartrate is highly dependent on temperature,<ref name=":5" /> the pure salt begins to crystallise out of solution, and can be collected via filtering once again.<ref name=":7" /> This solubility can also be exploited to produce potassium from Seignette's Salt (also known as Rochelle's Salt or [[potassium sodium tartrate]]). Acidification to pH 3.5 with small amounts of hydrochloric acid will precipitate potassium bitartrate.<ref name=":6" />
{{Expand section|date=August 2019}}

==See also==
* [[Tartrate]]
* [[Tartaric acid]]
* [[Potassium tartrate]] (K<sub>2</sub>C<sub>4</sub>H<sub>4</sub>O<sub>6</sub>)
* [[Potassium bicarbonate]]

==References==

{{Reflist}}

==External links==
{{wikt|tartar}}
* [http://www.monashscientific.com.au/PotassiumBitartrate.htm Description of Potassium Bitartrate at Monash Scientific]
* [https://web.archive.org/web/20141026125201/http://static.fishersci.com/cmsassets/downloads/segment/ScienceEducation/pdf/Chemicals/MSDS/S25477_BP6000.pdf Material Safety Data Sheet (MSDS) for Potassium Bitartrate at Fisher Scientific]
{{Potassium compounds}}

{{DEFAULTSORT:Potassium Bitartrate}}
[[Category:Acid salts]]
[[Category:Potassium compounds]]
[[Category:Tartrates]]
[[Category:Leavening agents]]
[[Category:Edible thickening agents]]