Nut Chocolates

Fat migration and fat bloom formation of chocolates with whole hazelnuts

Workgroup: Chocolate technology

Scientific Partners and Guidance:
Fraunhofer Institute for Process Engineering and Packaging IVV, MR. W. Danzl

Financing: IVLV
Duration: 2014 – 2015

Chocolates with whole nuts or coarse nuts are popular chocolate products. Like filled products nut oil migrates into the chocolate matrix and can produce a special type of fat bloom around the nuts, which is a known problem. The causes for fat bloom do not only lie on the chocolate part (solid fat content, tempering) put can also be found on the nuts part. Type of nut, quality and processing of the nuts may have a major influence. In addition the chocolates used for such products often contain already grinded nuts or nut oils. The complex interaction of these factors make the question for the correlation off fat migration and fat bloom a thrilling and challenging task.

Works done 2014

In the running project 2014 the focus was on the nut quality. Therefore in May 2014 two different types of nuts were roasted with different roasting conditions. The change in micro structure and the influence on free and mobile oil were investigated. With some examples, oil migration and fat bloom formation in chocolate bars was being examined.


The influences on fat bloom can have different reasons. The new small scale chocolate pilot plant at Fraunhofer IVV gives ideal conditions to pick up these questions and try to give answers on this topic. Furthermore some samples from industry will be investigated

Parameters on fat migration and fat bloom:

  • Type of chocolate
  • Tempering of chocolates
  • Tempering of nuts
  • Provenience of the nuts
  • Type and intensity of nut roasting

The project team will provide chocolates and nuts in different qualities. Fraunhofer IVV will produce well defined chocolates with these raw materials. Different tempering of nuts and chocolates will be performed. The produced chocolate bars will go into a storage test and the parameters fat migration (DSC, NMR) and fat bloom (visual and Digieye) will be investigated. Furthermore some samples from industry will be investigated.

Project Reports