Dusting of chocolate truffles with a cocoa powder
A chocolate “truffle” is a soft or hard chocolate confectionery centre on which a powder – cocoa or else – is dusted to enhance the appeal and the taste.
The core product if made of varying mixes of chocolate, cocoa powder, dairy cream, fat … The shape is obtained by a moulding or an extrusion process.
Depending of the forming process, the surface will be respectively hard and dry or soft and sticky (due to the cocoa fat content).
Other masses can be used such as fruit paste or marzipan.
If the core product results from a moulding process, its surface is generally “dry” and not sticky.
It requires the preliminary application of a sticking medium to trap the powder :
- Fluid chocolate – see the Chocolate enrobing process
- An hydrocolloid solution is an alternative.
If the core product results from an extrusion process and its composition is adequate, the surface is “sticky” and ready to catch a powder.
The powder used for dusting are :
- Cocoa powder, the obvious choice
- Icing sugar
- Fruit powders
- Any other suitable fine powder such as exotic ground spices (cinnamon, red pepper …)
How does it work?
The wet or wetted truffles must be exposed to the cocoa powder and be tumbled in it.
Subsequently they must be separated from the bed of powder. The adhesion time is relatively short. The separation process should remove the powder which is not adhering to the sticking medium.
The excess powder is sifted to remove chocolate particles and it is recycled. Fresh powder is brought in to compensate for the powder used. The process runs as follows
Enrobing with a chocolate layer or else
Powdering while tumbling
Separating the powder, sifting and continuous recycling
Cooling to set the chocolate layer
Different systems canbe used to form a bed of powder, tumble the truffles in it and separate them.
- A vibrating tray
- A mesh conveyor system as used to coat nuggets with breadcrumbs
- A rotating tumbler
- A rotating screw or twin-crew system
The choice of the tumbling motion drives the selection of the system. The sifting and recycling operations must also be considered carefully as they are the difficult to achieve without losses and pollution.
Tumbling in continuous screw system with a sieving and recycling zone is a solution. Example : twin-screw dusting sytem – Sugar InProcess
How do you measure your success?
Key quality features
The experience should be as close as possible to an artisanal cocoa dusted truffle
Even distribution of the cocoa powder
Deformation of the product up to a certain level may desired
The powder shoud hold and not be absorbed by the wet surface of the truffle
Key quality parameters
The producer should master a set of parameters
It can be cocoa powder of specific fat content, or else such as dried fruit powder
The motion applied to the product depends on principle (conveyor, screw, vibrating tray), design and operation (speed)
The base being chocolate, a careful control of the temperature during and beyond the process is critical