• With good knowledge and correct processing, chocolate can be shaped and used to obtain a wide variety of preparations or finished products.
Here I have clarified some basic aspects regarding this superior raw material:
• What is Chocolate?
• What is Chocolate Surrogate?
• What are the differences between Chocolate and Surrogate?
• Chocolate, the noble ingredient!
Only now, when these aspects are clear, we can talk about how to work with chocolate.
Why should chocolate be tempered?
Only through the tempering process can chocolate maintain its optimal characteristics over time:
– gloss on the surface of the product
- a perfect crystalline structure
- rigid structure, without stretching at break, being characteristic of that noise ,,crisp"
- good conservation
Only through the Tempering process:
– working with chocolate and modeling it can be done safely;
– the chocolate can be easily and completely extracted from the molds in which it was poured.
An untempered or incorrectly tempered chocolate can be recognized as follows:
– it will have an unpleasant appearance and will be opaque (without gloss),
- its structure will be sandy,
- the surfaces will show obvious formations of cocoa butter,
– in a short time it will know a rapid organoleptic degradation,
– it will be extremely difficult or even impossible to extract from the forms in which it was cast.
Tempering is the key stage in working with chocolate, being a complex process that requires understanding, knowledge and experience. To better understand this process, it is important to know the composition of chocolate! So let's remember!
Let's also remember that: Chocolate Surrogate does not temper!
Crystallization of Cocoa Butter
It is equally important to know the behavior of cocoa butter in chocolate! Let's see why?!
Working with chocolate is influenced by the way of crystallization (solidification) of cocoa butter, this noble fat that incorporates all the other solid parts that make up chocolate.
All these solid particles – cocoa, extrafine sugar crystals covered with soy lecithin molecules, which help to disperse and mix sugar in fats, vanilla, powdered milk (for the variety with milk), etc. – are in suspension in the butter cocoa.
By heating or cooling, cocoa butter has the ability to change its state, from liquid to solid and vice versa. Moreover, through solidification, various types of crystals are formed in the structure of cocoa butter, more precisely 6 types of crystals, different from each other in shape, size and melting point.
This process is called Polymorphism and consists in the ability of cocoa butter to form crystals of various types, with different properties, respectively to crystallize in 6 different forms.
Thanks to this polymorphism, the cocoa butter will crystallize (solidify) in one of these 6 crystalline forms (also called crystallization phases), depending on the working method adopted, more precisely, depending on the cooling method. In all 6 crystalline forms, both the structure and the melting temperatures will be different.
Of all these 6 types of crystals only one has the ability to remain stable over time. Thus, by crystallization of cocoa butter with this unique type of stable crystals, a V-type or β2-shaped structure is obtained.
This form of crystallization is the only one capable of providing chocolate, after the final crystallization: gloss and rigidity, but also the ability to melt in the mouth, having a melting temperature slightly lower than the temperature of the human body.
In the table below, you can see the behavior and the various melting points of chocolate, in the case of the 6 crystallization forms (types) of cocoa butter.
Starting from this general picture we can better understand the mechanisms of crystallization of cocoa butter in the 6 forms.
Forms of Crystallization I, II and III
Through a rapid cooling of the melted chocolate, in the refrigerator, it will reach Form I of Crystallization, with an average melting point of 17°C. Being an unstable form, it will rapidly migrate to the unstable forms II and III, which have a melting point between 22 and 25°C.
These 3 forms of crystallization are all unstable and undesirable, because the chocolate will become opaque, a little crunchy and as soon as we touch it, it will melt, due to the very low melting point.
In the case of milk chocolate, due to the presence of other types of fat, related to the addition of powdered milk, the temperatures can be a few degrees lower, depending on the percentage of powdered milk used.
All 3 of these crystalline, low-melting forms are created when molten chocolate is cooled very quickly and at very low temperatures. Over time, by preserving the chocolate at temperatures between 16 – 21°C, these forms of crystallization will migrate to the type IV form.
Form of Crystallization IV
By letting the melted chocolate crystallize at room temperature, a mixture of type IV crystals (average melting point at 27°C) and type V crystals (average melting point at 33°C) will be obtained, thus obtaining this form of crystallization unstable over time.
Form of Crystallization V
The V-type crystallization form is the one to be obtained by chocolatiers or confectioners!
This is the only stable form that will give chocolate: gloss, rigidity, the quality of melting easily in the mouth... Only through this form of crystallization can you obtain quality chocolate products, and the quality will remain stable over time!
The question that arises now that we understand this process is: How can this stable form (V) of crystallization be obtained?
From the analysis of the table, it appears that crystallized chocolate in form IV has a melting point of 27°C. Starting from this clue, we could consider that by cooling the melted chocolate to 30°C, for example, it could automatically crystallize in the shape we want, namely in the V shape. Unfortunately, it won't happen like that!
Recent studies have shown that obtaining a V-type crystallization under static conditions (without stirring, stretching, pressing, stirring the chocolate, etc.) is practically impossible. For this reason, it is necessary to resort to a more complex procedure, Tempering.
One of the qualities of chocolate crystallized in this unique stable form is Contractility (mandatory feature in working with chocolate). Due to this very compact crystalline form, upon crystallization, the chocolate will have the ability to contract (squeeze). Thus, the chocolate will detach from the walls of the forms in which it was poured, being very easy to extract from them.
Form of Crystallization VI
From a thermodynamic point of view, this is the most stable crystallization form at room temperature, but it does not provide the properties necessary for working with chocolate.
It must be taken into account that even chocolate tempered in the most correct way possible, in the situation of its preservation at ambient temperature, sooner or later, will reach the unstable form of type VI crystallization. In just a few months of storage at room temperature, the chocolate will reach this stage.
The higher the storage temperature of the chocolate, the faster the transformation and migration to form VI will be. This transformation is very often accompanied by the formation of an unwanted whitish patina on the surface of the chocolate. The spots thus formed are nothing but free cocoa butter (which melted at some point and then crystallized freely).
Good tempering of chocolate and its correct preservation will, however, reduce the probability of the appearance and formation of this unpleasant aspect.
Somewhat curiously, milk chocolate is exempt from this inconvenience because the milk fat prevents the cocoa butter from migrating to the surface of the chocolate. Beyond this disadvantage, due to the specific melting point of the VI crystallization form (36°C), the chocolate will melt much more difficult in the mouth, an aspect that will not be appreciated by consumers. Some of the crystals formed at this stage melt at even higher temperatures, which will contribute to the formation of small solid agglomerations, which, upon tasting, will be perceived negatively by consumers. That's why old chocolate or chocolate preserved in improper conditions can be recognized immediately, both by appearance and by tasting!
Article written by Gabriela Poteraș, Nova Pan Deputy Director, in collaboration with Pastry Chef Riccardo Magni
Read the first part of this article 👉 click "Chocolate Processing (1)".
