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17/05/2024

The Conching Chocolate Process

Updated on: 17/05/2024

Conching chocolate is a fundamental step in the Chocolate Manufacturing process. Read the following blog to learn all about it, or navigate this content menu and find answers to your questions:

The process behind a deliciously flavoured and smooth chocolate

For many consumers, little is known about how much is done to a cocoa bean before it can be turned into chocolate. More than a mystical metamorphosis, this transformation brings nature, science, and art together. To bring a chocolate couverture to life, fermented and dried cocoa beans are selected, winnowed, roasted, ground, mixed (with other ingredients), refined, and finally conched.

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Continue reading below to discover more about the process behind Luker’s chocolate products:

The conching process was discovered in 1879 by the Swiss chocolate maker Rudolph Lindt. Having accidentally left a mixer containing chocolate running overnight, he woke up to realise that this had changed the chocolate’s flavour and texture. The name of the equipment, the conche, is derived from the Latin word ‘shell’, as the traditional conche used in chocolate manufacturing resembled a conch shell.

Nowadays, the conching process is the final step in the manufacturing of chocolate. Whether it’s milk or dark, it is an essential process that contributes to developing viscosity, final texture, and flavour. For Luker especially,  conching is a magical process. This is an opportunity for us to work with clients and our development team’s expertise to build various flavour profiles. With just a little help from technology, you can start with one flavour and completely transform it into another. 

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What is conching in chocolate making?

Conching is a vital part of chocolate making. It entails the continuous mixing, grinding, and kneading of chocolate mass over a prolonged period. The conche, a machine specially designed for this purpose, is used in the process.

The chocolate is heated and stirred during the conching process while undergoing mechanical shear forces. This process achieves several essential objectives consistently.

  1. Texture development: Conching helps the chocolate develop a smooth and velvety texture. The agitation and kneading action reduce the particle size of cocoa solids and sugar, resulting in a fine, homogeneous mixture.
  2. Flavour enhancement: Conching contributes to developing the desired flavour profile of the chocolate. It allows the volatile flavours to evaporate, which can eliminate any harsh or unwanted flavours. Additionally, the process promotes the interaction between cocoa solids and cocoa butter, leading to the release of flavour compounds and the formation of desirable aromatic notes.
  3. Moisture removal: During conching, any residual moisture in the chocolate is evaporated, enhancing the shelf life and stability of the final product.
  4. Chemical and physical changes: Conching promotes chemical reactions, such as acid-base reactions, oxidation, and reduction processes, which can further refine the flavour and colour of the chocolate—additionally, conching aids in reducing the acidity of cocoa and improving its pH.

Horizontal vs. Vertical Conching

When we are in this step of the chocolate-making process, we must remember that there are two ways of performing the conching process: Vertical and Horizontal conching.

Which to choose depends on various factors, as each performs slightly differently depending on the origin of the cocoa beans, the type of chocolate that we are trying to make (dark, milk, or white), the volume of raw materials being processed, and the flavour we want to achieve.

The main difference between these types of conching is how the axis of the conch machines is set up. Both of them get the work done. However, the horizontal one has the advantage that it can complete steps in the dry and plastic phases, which helps enhance the development of flavour and rheology.

Importance of conching for the chocolate-making process:

Amongst the chocolate-making industry, we talk about ‘cocoa solids’ as particles that carry all the colour, taste, and most of the nutritional value of a chocolate bar. However, these particles also happen to have intense bitter and astringent notes, which are given by polyphenols or antioxidants in cocoa. Additional off-flavours such as acetic acid are also leftover from the fermentation process.

This processing step, which consists mainly of mixing, shearing, and aeration of the chocolate mass at a certain temperature and for a certain amount of time, is considered a critical step for two main reasons:

  1. During conching, the tiny particles of solids (often cocoa, sugar, and milk) acquire a more uniform shape to be coated evenly with cocoa butter. This gives chocolate its viscosity, flow, and textural properties and determines the way in which the finished product will melt smoothly in the mouth.
  2. The conching process promotes flavour development through several factors such as time, temperature, and the other ingredients in the recipe. But it also removes moisture and volatile flavours (short-chained fatty acids and aldehydes) that are highly related to the origin and characteristics of the cocoa beans. This is one of the most important reasons for which the conching process at Luker Chocolate is different from other chocolate manufacturing companies.

Amongst the scientific community, different researchers have put forward differing opinions on how many phases there are in the conching process. Some researchers define conching as a two-phase process. In the first stage known as the ‘dry phase’, the moisture level is reduced. Some volatile acids like acetic acid caused by cocoa fermentation are removed, and the surfaces of all solid particles are covered with fat. In the second stage, called the ‘wet phase’, homogenous and paste-like fluid mass is obtained by adding more cocoa butter and emulsifiers.

On the other hand, some say that this process has three phases. This is also what we believe and perform at Luker Chocolate which can be described as follows:

What does the process of conching chocolate actually look like?

Play the above video:

On the other hand, some say that this process has three phases. This is also what we believe and perform at Luker Chocolate, which can be described as follows:

Phases involved when conching chocolate:

1. DRY PHASE

Chocolate mass being transferred

Chocolate mass being transferred from the refiner  

The chocolate mass is transferred from the refiner, generally as flakes, to be heated, mixed and aerated. The primary objective of this stage is to allow the evaporation of some of the volatile acids from cocoa liquor and the water originating from the chocolate components. The total concentration of acetic acid after the dry conching stage remains approximately constant as there is no free water that acts as a vapour carrier.

2. PLASTIC PHASE

Cocoa flakes turning into a paste

Cocoa flakes turning into a paste as cocoa butter is added

Next, the mass which is mixed, sheared, heated and degassed enters the second phase that we call the ‘long step’. At this stage, flavour characteristics are developed through chemical reactions (Maillard reaction and Strecker’s degradation ) given by the process’ time and temperature conditions. This is also another important step to reduce the volatilisation of acetic acids, due to cocoa fermentation.

It is called the ‘plastic phase’ because of the physical change that occurs to the mass, turning from flakes into a paste and becoming more liquid as the cocoa butter covers the solid particles. Time and temperature play a key role in this stage. The temperature is more closely related to the type of chocolate being manufactured (dark, milk or white). While time has to do with factors dependent on the quality and variety of beans used to produce the cocoa liquor.

3. LIQUID PHASE

final phase as milk chocolate

The final phase as milk chocolate is being conched

This phase is the shortest and it is where the viscosity and flow properties undergo the final adjustments, with the addition of cocoa butter and emulsifiers.

The technology used is extremely important (i.e., actual conching machinery designs are more efficient in terms of energy and time). In the conching process during the plastic phase, normally milk chocolates are conched at around 50°C to prevent the caramelisation of the product. Should the temperature be any higher, this causes lumps and sandiness in the mouth when eating the final product.

Some dark chocolates, on the other hand, can be conched up to 90°C because of their intense load of volatile by-products from fermentation. However, conching time is a big discussion point at this stage, because it is here that the quality, type and the origin of the beans play a determinant role.

Throughout the years, Luker Chocolate has built extremely close relationships with Colombian farmers, sharing knowledge and experience. This guarantees exceptional quality characteristics by the end of the fermentation process and the drying of the cocoa beans. Supported by the Colombian ‘Fino de Aroma’ cocoa beans which are naturally complex in their flavour profile with delicate fruity, floral, and herbal notes, we take great care in applying temperature and conching time for every chocolate couverture we produce. Luker can deliver finished products to customers worldwide with unique, high-quality flavour experiences.

This is how we do it in our manufacturing plant:

Here at Luker Chocolate, with state-of-the-art technology and our Colombian Fine Flavour cocoa beans, our conching process ranges from 2 to 7 hours. This length of time makes us different in terms of processing conditions during chocolate manufacturing. There is more to keep, such as the aromatic compounds of vanilla or the fruity or caramel-like flavours than take away from the original product. Parallel to this, we must develop the fluidity and mouthfeel of the product to maintain a luxury experience.  

Within this time period, it’s also important to remember that the senses of taste and smell are in the form of volatile molecules. During the conching process, these molecules are what is responsible for the aroma and flavour. However, like a perfume, if left open for a long period of time and shaken about, you will lose the original aroma. 

Other companies around the world that manufacture chocolate couvertures, working with bulk cocoa beans, can apply conching processes from 12 to 78 hours. This is due to the high levels of acetic acid and other compounds that can have a negative impact on the final flavour of the chocolate. A disadvantage in terms of production efficiency is due to the long heat treatment and high sheer (costs and energy), as well as a less indulgent and delicious sensory profile one would expect from chocolate. With an exquisite profile such as the Fino de aroma cacao, we don’t want our cocoa to taste plain and lose all its beauty! So, by using high-quality products and shorter time periods, we don’t have to compromise all the amazing characteristics during the process.

We hope that with this information, the next time you eat chocolate, you can close your eyes and pay attention to the texture as the chocolate melts in your mouth. Take a slight breath of air to assess the flavour and remember that behind that complexity, the joint work of science and nature is the magic behind your new sensory experiences.

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