The chemical, pharmaceutical and food industries generate an average output of 300,000 tonnes of solid products per company per year. Caking of these products is therefore a major concern to the industry. This paper concentrates on caking due to crystal bridges formed under the influence of humidity. Using the micro-macro approach, it is shown how the bulk strength of caked solids can be predicted from individual particle contacts. The individual particle contact measurements are performed in a new test device, the DAPP system, built for particles in the half-millimetre size range. For the modelling, a contact-dynamics model was adapted to caked systems. It proved important to use the complete crystal bridge strength distribution in the simulation. Under these conditions modelling and validation experiment coincided to a factor of two. (C) 2008 Elsevier B.V. All rights reserved.