Chocolate and Cocoa

Barry_Callebaut

The manufacture of chocolate involves the roasting of cocoa beans followed by grinding them to form cocoa mass. Some of this cocoa mass is pressed to release the fat, cocoa butter, and the remaining solids when milled are known as cocoa powder.

Types of chocolate

Plain or dark chocolate is a blend of cocoa mass, sugar and cocoa butter with traces of emulsifier and vanilla (or other flavours). It has a strong slightly bitter flavour.

Milk chocolate is a blend similar to dark chocolate but in addition it includes milk crumb which is made from dried milk. It contains less cocoa mass than dark chocolate so it is paler in colour and the presence of butter fats reduces the chocolate melting point.

In all cases the chocolate is the result of fine grinding (refining) followed by conching (a prolonged mixing process) which modifies the flavours, reduces the moisture content to very low levels and ensures a very good dispersion of the fat over the solid particulates.

Supply and storage of chocolate

Most biscuit factories do not manufacture their own chocolate so it is necessary to consider only delivery and storage.

For large users it may be convenient and more economic to bulk handle chocolate in warm liquid form. Road tankers are used to carry and discharge the chocolate in a similar way to fats. The silos must be jacketed, kept at 49°C, and the chocolate must be constantly agitated in a gentle manner. The minimum temperature for bulk chocolate storage is 45°C. This ensures that all the fat is liquid. Great care should be taken to avoid contact with water or damp surfaces as even traces of moisture will cause a great increase in the chocolate consistency. As for fats, no valves or other fittings should contain copper or brass which will promote rancidity. In general, chocolate is much more resistant to rancidity than pure fats, so storage in liquid form can safely be for several weeks.

Many users take delivery of chocolate in solid form. This may be in large blocks or in small pieces. The large blocks will have been moulded at the supplier's factory and wrapped in plastic or waxed paper to protect against atmospheric humidity. In the case of small pieces, these may have been moulded, deposited or cooled as strips which are subsequently broken in a random way before bulk packing in moisture proof sacks for shipment.

Solid chocolate should be stored in rooms at about 15°C with a relative humidity of 50% or less and well away from strong smelling ingredients such as spices, cheese and chemicals. The value of chocolate combined with its appeal to most people usually requires that it is kept under lock and key!

Prior to use in an enrober or moulding plant the chocolate has to be melted. Melting kettles are normally heated with hot water and it is important that surface temperatures are maintained below 60°C otherwise there is a risk of flavour change (and damage to the lecithin) - a metallic flavour may be detectable if chocolate has been overheated. The advantage of small pieces of chocolate compared with larger blocks is that they are easier to handle and they melt more rapidly.

The handling of melted chocolate requires special equipment to "temper" it before application onto biscuits. The techniques of tempering, enrobing and moulding of chocolate is covered on this link.