Conche
Encyclopedia
A conche is a surface scraping mixer and agitator that evenly distributes cocoa butter
within chocolate
, and may act as a 'polisher' of the particles. It also promotes flavor
development through frictional
heat and release of volatiles and acids, and oxidation. There are numerous designs of conches, and food scientist
s are still studying precisely what happens during conching and why. The name arises from the shape of the vessels initially used, which resembled conch
shell
s.
When ingredient
s are mixed in this way, sometimes for up to 78 hours, chocolate
can be produced with a mild, rich taste. Lower quality chocolate is conched for as little as six hours. Since the process is so important to the final texture and flavor of chocolate, manufacturers keep the details of their conching process proprietary.
The "conche" was invented by Rodolphe Lindt (1855-1909) in Berne, Switzerland, in 1879 producing aroma and melting characteristics in chocolate of superior quality at that time. Legend
has it that he mistakenly left a mixer
containing chocolate running overnight, and though he was initially distraught at the waste of energy
and machine wear and tear, quickly realized he had made a major breakthrough. Before conching was invented solid chocolate was gritty and not very popular. Lindt's invention rapidly changed chocolate from being mainly a drink, to bars and other confections.
Lindt's original conche consisted of a granite roller and granite trough; such a configuration is now called a "long conche" and can take a day or more 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, called the McIntire mixer, can carry out all the steps of grinding, mixing and conching required for small batches of chocolate.
phase
the substances from the dry cocoa
that create flavor. Air flowing through the conche removes some unwanted acetic, propionic, and butyric acid
from the chocolate and reduces moisture. A small amount of moisture greatly increases viscosity
of the finished chocolate, so machinery is cleaned with cocoa butter instead of water. Some of the substances produced in roasting of cocoa beans are oxidized in the conche, mellowing the flavour 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 49 C for milk chocolate to up to 82 C for dark chocolate. The elevated temperature leads to a partially caramelized
flavor, and in milk chocolate promotes the Maillard reaction
.
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.
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, which may be adjusted depending on the intended use of the chocolate. Fats and emulsifiers are added to adjust the viscosity, and thoroughly mixed.
While most conches are batch process machines, continuous flow conches separate the stages with weirs, over which the product travels through separate parts of the machine. A continuous conche can reduce the conching time for milk chocolate to as little as four hours.
Cocoa butter
Cocoa butter, also called theobroma oil, is a pale-yellow, pure edible vegetable fat extracted from the cocoa bean. It is used to make chocolate, biscuits, and baked goods, as well as some pharmaceuticals, ointments, and toiletries...
within chocolate
Chocolate
Chocolate is a raw or processed food produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America. Its earliest documented use is around 1100 BC...
, and may act as a 'polisher' of the particles. It also promotes flavor
Flavor
Flavor or flavour is the sensory impression of a food or other substance, and is determined mainly by the chemical senses of taste and smell. The "trigeminal senses", which detect chemical irritants in the mouth and throat as well as temperature and texture, are also very important to the overall...
development through frictional
Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...
heat and release of volatiles and acids, and oxidation. There are numerous designs of conches, and food scientist
Food science
Food science is a study concerned with all technical aspects of foods, beginning with harvesting or slaughtering, and ending with its cooking and consumption, an ideology commonly referred to as "from field to fork"...
s are still studying precisely what happens during conching and why. The name arises from the shape of the vessels initially used, which resembled conch
Conch
A conch is a common name which is applied to a number of different species of medium-sized to large sea snails or their shells, generally those which are large and have a high spire and a siphonal canal....
shell
Seashell
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer created by an animal that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers...
s.
When ingredient
Ingredient
An ingredient is a substance that forms part of a mixture . For example, in cooking, recipes specify which ingredients are used to prepare a specific dish. Many commercial products contain a secret ingredient that is purported to make them better than competing products...
s are mixed in this way, sometimes for up to 78 hours, chocolate
Chocolate
Chocolate is a raw or processed food produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America. Its earliest documented use is around 1100 BC...
can be produced with a mild, rich taste. Lower quality chocolate is conched for as little as six hours. Since the process is so important to the final texture and flavor of chocolate, manufacturers keep the details of their conching process proprietary.
The "conche" was invented by Rodolphe Lindt (1855-1909) in Berne, Switzerland, in 1879 producing aroma and melting characteristics in chocolate of superior quality at that time. Legend
Legend
A legend is a narrative of human actions that are perceived both by teller and listeners to take place within human history and to possess certain qualities that give the tale verisimilitude...
has it that he mistakenly left a mixer
Mixer (cooking)
A mixer is a kitchen appliance intended for mixing, folding, beating, and whipping food ingredients. Mixers come in two major variations, hand mixers and stand mixers....
containing chocolate running overnight, and though he was initially distraught at the waste of energy
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
and machine wear and tear, quickly realized he had made a major breakthrough. Before conching was invented solid chocolate was gritty and not very popular. Lindt's invention rapidly changed chocolate from being mainly a drink, to bars and other confections.
Lindt's original conche consisted of a granite roller and granite trough; such a configuration is now called a "long conche" and can take a day or more 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, called the McIntire mixer, can carry out all the steps of grinding, mixing and conching required for small batches of chocolate.
Conching process
The conching process redistributes into the fatFat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
phase
Phase (matter)
In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, and chemical composition...
the substances from the dry cocoa
Cocoa solids
Cocoa solids are the low-fat component of chocolate. When sold as an end product, it may also be called cocoa powder, cocoa, and cacao....
that create flavor. Air flowing through the conche removes some unwanted acetic, propionic, and butyric acid
Butyric acid
Butyric acid , also known under the systematic name butanoic acid, is a carboxylic acid with the structural formula CH3CH2CH2-COOH. Salts and esters of butyric acid are known as butyrates or butanoates...
from the chocolate and reduces moisture. A small amount of moisture greatly increases viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
of the finished chocolate, so machinery is cleaned with cocoa butter instead of water. Some of the substances produced in roasting of cocoa beans are oxidized in the conche, mellowing the flavour 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 49 C for milk chocolate to up to 82 C for dark chocolate. The elevated temperature leads to a partially caramelized
Caramelization
Caramelization is the browning of sugar, a process used extensively in cooking for the resulting nutty flavor and brown color. As the process occurs, volatile chemicals are released, producing the characteristic caramel flavor....
flavor, and in milk chocolate promotes the Maillard reaction
Maillard reaction
The Maillard reaction is a form of nonenzymatic browning similar to caramelization. It results from a chemical reaction between an amino acid and a reducing sugar, usually requiring heat....
.
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.
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, which may be adjusted depending on the intended use of the chocolate. Fats and emulsifiers are added to adjust the viscosity, and thoroughly mixed.
While most conches are batch process machines, continuous flow conches separate the stages with weirs, over which the product travels through separate parts of the machine. A continuous conche can reduce the conching time for milk chocolate to as little as four hours.