The differential rate and extent with which molasses-based feed supplements are fermented in the rumen, relative for example to starch-based concentrates, could be used to position these products in the market. There are, however, currently no data available to support such an assertion, in part due to the problem of how to assess degradation, as clearly standard feed evaluation methodologies such as the nylon bag technique (Ørskov et al., 1980) are inappropriate for liquid feedstuffs. The ability of the recently developed Reading Pressure Technique (RPT) (Mauricio et al., 1999) to examine such feeds was therefore utilised to describe or “fingerprint” the fermentation profiles of a range of commercially available molasses-based feeds.