The hydrophile-lipophile balance (HLB) was used to characterize several naphtha-diluted bituminous froth and bitumen phases, extracted froth components, and commercial demulsifiers used to resolve the froth emulsions. The requirements for emulsification of the diluted froth and bitumen phases could be classified by the HLB system in terms of required HLB values. Although such classification was not effective in detecting gross changes in the interfacial components of the diluted froth and bitumen phases. meaningful HLB values were obtained for the water soluble natural surfactants (HLB 16 +/- 1) and asphaltenes (HLB 11 +/- 1) isolated from the froth. The HLB values for three commercial demulsifiers were found to change depending on the delivery medium, from 12 I if the demulsifier was dissolved in naphtha to 7 I if the demulsifier was dissolved in water. This difference in apparent HLB may arise from differences in interfacially active components in the diluent. It appears that demulsifier components delivered in naphtha and the water-soluble natural surfactants will seek to form O/W emulsions and, therefore, act to destabilize the W/O froth emulsions. Conversely, demulsifier components delivered in water and naturally occurring asphaltenes will act to stabilize the W/O froth emulsions. (C) 2002 Elsevier Science B.V. All rights reserved.