This work investigates cavitation patterns after a cylindrical coaxial orifice at different orifice to outlet channel diameter ratios beta < 0.1. Further the influence of cavitation pattern on emulsion formation efficiency in high pressure homogenization is shown. At constant pressure loss (Delta p) and varying beta, three characteristic cavitation patterns (jet cavitation, choked cavitation and hydraulic flip) were detected via high speed imaging and acoustical measurement. The study shows that a surfactant concentration up to 10(-4) mol center dot L-1 and disperse phase content up to 10 wt.% do not influence cavitation pattern transition in the investigated fluid. Emulsification results indicate decreasing emulsification efficiency with increasing beta and thereby a strong correlation to the detected cavitation patterns. (C) 2015 Elsevier Ltd. All rights reserved.