Objective To study the effects of the beverage bottle opening size on drinking feelings in order to elevate the comfort of consumers when drinking from the bottles. Methods An investigation over 160 cases was performed based on a drinking feelings test using three kinds of bottles with opening diameters of 28, 33 and 38 mm, respectively. Results The factor analysis results showed that the drinking feeling was affected by factors such as the flow from the bottle to the mouth and the flow adjustability. Moreover, a finite fluid analysis model was developed to simulate the bottled liquid in a drinking action. Through the simulation analysis, we understood how consumers control the flow rate during the drinking actions to realize the ideal feeling by adjusting the inclination angle of the bottle. Conclusion Statistical analysis results showed that 33 mm opening was the optimum for adult consumers regardless of the gender and the mouth size.