Within a European research programme (AIR-CT-94-2039), a group of researchers undertaking sensory analysis of cheese applied itself to standardizing panel training methods A common methodology to characterize smell, aroma, taste and trigeminal sensations, that is to say olfactory and gustative properties of hard and semi-hard cheeses was determined. These properties were evaluated on five Protected Designation of Origin cheeses (PDO) by panels working in four countries Without neglecting the importance of texture on aroma perception, the group defined an evaluation scale for the different characteristics. Odours and aromas were classified in odour and aroma families that were tested by the panels. A cheese aroma wheel is proposed. Along with the former methodology for sensory evaluation of texture published in 1993 the present work completes the methodology for the sensory characterization of hard and semi-hard cheeses made from cow milk. (C) 1997 Academic Press Limited