Italian Modern Artisan Chocolate: The Agostoni famly passion for over sixty years.

Master's advices

Tempering

The processing of chocolate, especially when used to coat and fill moulded items, is strongly affected by the specific solidifying properties of the cocoa butter. When cocoa butter is cooled, it usually takes up several crystalline forms.

Polymorphism and monotropism of cocoa butter
At least 5 crystal types have been identified, which differ in shape, structure, size and melting point (polymorphism). In addition only one or two types of crystal maintain stable over time, whilst all the others are highly instable, as they tend to melt independently and to re-crystallise subsequently (monotropism).
The purpose of the tempering process is to select the crystals of cocoa butter only in the stable form, so that the chocolate can maintain its optimal properties over time: sheen, ease of shaping, perfect crystalline structure, snapping properties and durability.
On the contrary, chocolate which becomes dull due to an incorrect tempering process, but also to variations in temperature, will have an opaque appearance, which may even lead to visible traces of cocoa butter on the surface (fat bloom). It will be difficult to mould, have a grain-like, inconsistent structure and will not easily melt in your mouth, plus a rapid organoleptic deterioration over time. The tempering process can usually be divided into 3 phases:

Melting

For the chocolate to melt perfectly, it must be heated to the temperature of 45°/50°C (for a sufficient length of time to melt the chocolate entirely) taking care that there are no remaining lumps and that it is perfectly fluid. This operation may be carried out using melting equipment, stoves and microwave ovens; in the latter case we recommend proceeding gradually in order to avoid product accidental burning.

Cooling (pre-crystallisation)

In this phase the mass of melted chocolate is cooled to a temperature of 25°/26° C for white chocolate, 27°/28° C for milk chocolate and 28°/29° C for dark chocolate. It is important that the mass of chocolate to be tempered be cooled evenly so that the crystals of cocoa butter are distributed evenly in the correct quantities. For this purpose it is useful to stir the chocolate mass continuously; many of the crystals which form during this phase belong to different types including both instable and highly instable types.

Heating (selection)

This refers to the heating of the pre-crystallised chocolate mass. This phase involves heating the mass (28°/29° C for white chocolate and 32°/33° C for dark chocolate). In this way, we select the crystals of cocoa butter because only the stable crystals resist this temperature, whilst the instable crystals have lower melting points: we can therefore proceed to manufacture and use the chocolate as required.

Tempering methods

There are several different methods for tempering chocolate. Naturally, we recommend that suitable tempering machines are used. However, if such equipment is not available we recommend using one of the following methods:

Tabling

The melted coating is worked on a cold surface (20°C) using a spatula, until the pre-crystallisation temperature is reached. At this point more coating is added at the temperature of 40° C in a ratio of 1 to 2 in order to reach the suitable processing temperature.

Injection or insemination

Heat the mass of melted chocolate to around 34°/35°C and leave to rest in a container. At this point a small quantity of tempered chocolate (5/10% of the mass) is added either in a single block or grated, and is carefully stirred in. When the temperature of 33°/34° C is reached, some crystals of cocoa butter (the more stable crystals belonging to the ß forms which have melting points above 34°C) which are present in the chocolate blend, will be able to resist melting and make other similar cocoa butter crystals adopt similar forms.
To carry out this method well, the greatest attention must be paid to the temperature which must lie between 33° and 35°C for all types of chocolate. A certain quantity of chocolate which has already been perfectly tempered must also be available. For this purpose we recommend that the chocolate to be worked should not be melted completely.

Direct method

Very gradually heat the mass of chocolate to an absolute maximum temperature of 33°/34° C. This operation may be carried out by heating the chocolate for a suitable length of time using a stove with a set temperature of 33°/34°C. A microwave oven may also be used for this purpose, making sure to proceed gradually.