Editing Conching

{{Short description|Process for refining chocolate by stirring at high temperature}}
{{redir|Conche}}
[[file:Conchiermaschine.ogg|upright=1.35|thumb|Conche (in the [[Imhoff-Schokoladenmuseum]])]]
[[File:Granite Roller and Granite Base of a Conche.jpg|thumb|Granite roller and granite base of a conche]]

'''Conching''' is a process used in the manufacture of [[chocolate]] whereby a surface scraping mixer and agitator, known as a '''conche''', evenly distributes [[cocoa butter]] within [[chocolate]] and may act as a "polisher" of the [[wiktionary:particle|particle]]s.<ref name=Afoakwa10/> It also promotes [[Flavoring|flavor]] development through [[friction]]al heat, release of [[volatile oil|volatile]]s and acids, and oxidation. The name arises from the shape of the vessels initially used which resembled [[conch]] [[seashell|shells]].

When [[ingredient]]s are mixed in this way, sometimes for up to 78 hours, chocolate can be produced with a mild, rich taste. Since the process is so important to the final texture and flavor of chocolate, manufacturers keep the details of their conching process proprietary.<ref name= McClements2007>McClements, D. Julian ''Understanding and Controlling the Microstructure of Complex Foods'', Woodhead Publishing, 2007, {{ISBN|978-1-4200-6573-2}}, page 654.</ref>

The conching techique was introduced in Switzerland in the late 19th century. Conched chocolates were distinguished from ordinary chocolates with the French adjective ''fondant'' or ''crémant''.<ref>{{cite web | url=https://www.chocosuisse.ch/fr/chocolat-suisse/fabrication | title=Chocolat suisse: fabrication | publisher=ChocoSuisse | accessdate=12 February 2025 | quote=On anoblit la pâte chocolatière en la chauffant et en la remuant pendant des heures, processus que l'on appelle le « conchage ». Ce faisant, le chocolat devient crémant et fondant.}}</ref>

== History ==

[[Rodolphe Lindt]] invented the conche in [[Berne]], in 1879. It produced chocolate with superior [[aroma]] and melting characteristics compared to other processes used at that time. The Lindt chocolate company states that Lindt (perhaps mistakenly) allowed a [[mixer (cooking)|mixer]] containing chocolate to run over a weekend (or possibly overnight, according to other variants of the possibly [[apocryphal]] story).<ref>{{cite web |title=The Lindt Invention |url=https://www.chocolate.lindt.com/world-of-lindt/the-lindt-difference/the-lindt-differencethe-lindt-invention-conching/ |website=chocolate.lindt.com |publisher=Lindt & Sprüngli |access-date=25 June 2020 |archive-date=17 October 2020 |archive-url=https://web.archive.org/web/20201017190410/https://www.chocolate.lindt.com/world-of-lindt/the-lindt-difference/the-lindt-differencethe-lindt-invention-conching/ |url-status=dead }}</ref> Upon returning to the device, Lindt recognised the final product to have a smoother texture and greater shine than conventionally processed chocolate of the time. Lindt's invention made the mass-production of [[chocolate bar]]s more practical, eventually replacing chocolate beverages as the primary means of mass chocolate consumption.<ref name=Talbot09>Talbot, Geoff (ed), ''Science and Technology of Enrobed and Filled Chocolate, Confectionery and Bakery Products'', Woodhead Publishing, 2009, {{ISBN|978-1-84569-390-9}}, chapter 2.5 ''Conching''.</ref> The adoption of conching also generalized the use of additional [[cocoa butter]] in the chocolate production; until then, molded chocolate often simply consisted of [[cocoa mass]] and sugar.<ref>{{cite book | title=The Manufacture of Chocolate and other Cacao Preparations | url=https://archive.org/details/manufactureofcho00zipp | publisher=E & F N Spon | author=Zipperer, Paul | year=1915 | location=London | pages=136-138 | quote=The relative proportions of cacao, sugar, and spices, as well as of starch as in the manufacture of the cheaper sorts, vary considerably. Generally speaking 50 or 60 parts of sugar are added for 50 or 40 parts of cacao mass [...] As far as can be ascertained, they [chocolats fondants] were first manufactured in Switzerland, melt readily, and have a correspondingly large amount of fat, resulting from the addition of cacao butter, which distinguishes them from ordinary chocolates.}}</ref>

The original machine used by Lindt was developed in the early 1800s by an Italian chocolatier named Bozelli.<ref>{{cite book | url=https://www.google.ch/books/edition/Chocolate/zwVS5gsJMUcC | title=Chocolate History, Culture, and Heritage | publisher=Wiley | author=Grivetti, Louis E. | year=2011 | pages=58 | quote=Rodolphe modified an old water-powered grinding machine developed by an Italian named Bozelli, by embedding iron troughs in granite with the upper edges curved inward.}}</ref> The Bozelli grinding process was based on ancient [[Mesoamerica]]n practices of grinding cocoa beans on curved stones,<ref>{{cite journal | url=https://www.google.ch/books/edition/Advances_in_Food_Research/TS_TeOA5QowC | title=Chocolate | author=Robert A. Martin Jr | journal=Advances in Food Research | year=1988 | volume=31 | pages=213-330 | quote=The process evolved from the ancient Mexican practice of hand grinding cocoa beans between a roller and curved plate. In the early 1800s the Bozelli grinding machine mechanized the process}}</ref> which were called ''[[metate]]s''.

Lindt's original conche consisted of a granite roller and granite trough; such a configuration is now called a "long conche" and can take more than a day to process a tonne of chocolate. The ends of the trough were shaped to allow the chocolate to be thrown back over the roller at the end of each stroke, increasing the surface area exposed to air. A modern rotary conche can process 3 to 10 tonnes of chocolate in less than 12 hours. Modern conches have cooled jacketed vessels containing long mixer shafts with radial arms that press the chocolate against vessel sides. A single machine can carry out all the steps of grinding, mixing, and conching required for small batches of chocolate.{{Citation needed|date=September 2021}}

The conching process remained mostly a trade secret until the end of the century.<ref>{{cite book |last1=Grivetti |first1=Louis |last2=Shapiro |first2=Howard-Yana |date=2011 |url=https://www.google.ch/books/edition/Chocolate/zwVS5gsJMUcC |title=Chocolate: History, Culture and Heritage |location=[[Hoboken, New Jersey]] |publisher=[[John Wiley & Sons]] |page=58 |author-link2=Howard-Yana Shapiro | quote=A separate conching building was built, with access limited only to authorized personnel. In 1899, the German magazine ''Gordian'' published a discussion entitled: "Why does this chocolate taste so different from all the others?"}}</ref> In the 1890s, [[Cailler]] launched a similar chocolate.<ref>{{cite book | url=https://www.google.ch/books/edition/Catalogue_officiel_de_l_Exposition_canto/1gBZGs6fW2UC | title=Catalogue officiel de l'Exposition cantonale vaudoise à Yverdon, 1894 | author=Exposition cantonale vaudoise | publisher=Rochat, A. | year=1894 | location=Lausanne | pages=81 | quote=On lui doit la fabrication du ''Chocolat crêmant'', spécialement destiné à être mangé à la main. Ce chocolat se distingue par l'extrême finesse de sa pâte, qui laisse au palais l'impression d'une crème fondante et savoureuse. Ce résultat n'a pu être acquis que grâce à un procédé spécial de fabrication. Ce produit, créé il y a deux ans environ, a conquis, dès l'abord une réputation justifiée et constante. | trans-quote=It is responsible for the production of "Chocolat crêmant", specially designed to be eaten by hand. This chocolate is distinguished by the extreme fineness of its paste, which leaves the palate with the impression of a melting and tasty cream. This result could only be achieved thanks to a special manufacturing process. This product, created about two years ago, has gained a justified and constant reputation from the outset.}}</ref> A long conche was manufactured by J. M. Lehmann from 1899.<ref>{{cite web | url=https://americanhistory.si.edu/collections/object/nmah_1301436 | title=Chocolate-Making Conch | publisher=[[National Museum of American History]] | accessdate=12 February 2025}}</ref>

== Process ==
[[File:Hershey Conche.jpg|thumb|A [[The Hershey Company|Hershey]] conche from the early 1900s, on display as part of the [[The Hershey Story|Hershey Story]] collection]]

Conching redistributes the substances from the [[cocoa solids|dry cocoa]] that create flavor into the [[fat]] [[Phase (matter)|phase]]. Air flowing through the conche removes some unwanted [[acetic acid|acetic]], [[propionic acid|propionic]], and [[butyric acid|butyric]] acids from the chocolate and reduces moisture. Even a small amount of moisture greatly increases the [[viscosity]] of the finished chocolate, so machinery is cleaned with cocoa butter instead of water.<ref name=RKB97>Ranken, M. D.; Kill, R. C.; Baker, C. G. J. (ed.), ''Food Industries Manual (24th Edition)'', Springer-Verlag, 1997, {{ISBN|978-0-7514-0404-3}}, pages 438–439.</ref> Some of the substances produced in the roasting of cocoa beans are [[oxidized]] in the conche, mellowing the flavor of the product.

The temperature of the conche is controlled and varies for different types of chocolate. Generally, higher temperature leads to a shorter required processing time. Temperature varies from around {{convert|49|C}} for milk chocolate to up to {{convert|82|C}} for dark chocolate. The elevated temperature leads to a partially [[Caramelization|caramelized]] flavor and in milk chocolate promotes the [[Maillard reaction]].<ref name=Afoakwa10>Emmanuel Ohene Afoakwa, ''Chocolate Science and Technology'', John Wiley and Sons, 2010, {{ISBN|1-4051-9906-7}}, pages 43, 65–66.</ref>

The chocolate passes through three phases during conching. In the dry phase the material is in powdery form, and the mixing coats the particles with fat. Air movement through the conche removes some moisture and volatile substances, which may give an acidic note to the flavor. Moisture balance affects the flavor and texture of the finished product because, after the particles are coated with fat, moisture and volatile chemicals are less likely to escape.<ref name=Talbot09/>

In the pasty phase more of the particles are coated with the fats from the cocoa. The power required to turn the conche shafts increases at this step.

The final liquid phase allows minor adjustment to the viscosity of the finished product by addition of fats and [[emulsifier]]s, depending on the intended use of the chocolate.

While most conches are batch-process machines, continuous-flow conches separate the stages with [[wiktionary:weir|weirs]], over which the product travels through separate parts of the machine.<ref name=Talbot09/> A continuous conche can reduce the conching time for milk chocolate to as little as four hours.<ref name=RKB97/>

After conching is completed, the flavor continues to change as it tastes increasingly acidic.{{Sfnp|Giller|2015}}

== See also ==
* [[Melanger]]
* [[History of chocolate]]

== References ==

{{reflist}}

== Sources ==
{{refbegin}}
* {{Cite web |last=Giller |first=Megan |date=2015 |title=Rogue Chocolatier: Why You've Never Heard Of The Best Chocolate Maker In America |url=https://www.chocolatenoise.com/rogue-chocolate/ |url-status=live |archive-url=https://web.archive.org/web/20240914121437/https://www.chocolatenoise.com/rogue-chocolate/ |archive-date=September 14, 2024 |access-date=December 13, 2024 |website=Chocolate Noise}}
{{refend}}

== Further reading ==

* {{Cite journal |last=Augusto |first=Pedro Pio C |last2=Bolini |first2=Helena M A |title=The role of conching in chocolate flavor development: A review |journal=[[Comprehensive Reviews in Food Science and Food Safety]] |volume=21 |issue=4 |doi=10.1111/1541-4337.12975 |pmid=35638351}}

== External links ==
* [http://www.grenadachocolate.com/tour/refining-and-conching/ Refining and Conching - Grenada Chocolate]
* [https://web.archive.org/web/20110705114427/http://www.lippmischtechnik.de/en/produkte/conchier-maschinen/ Manufacturer's illustration of production-size conche and mixing shaft]

{{Chocolate}}

[[Category:Chocolate]]
[[Category:Cooking techniques]]
[[Category:Articles containing video clips]]
[[Category:Swiss inventions]]