How Wide Do You Want the Jar?: The Effect on Diameter for Ease of Opening for Wide-mouth Closures

The ease with which a container can be accessed or its 'openability' is becoming more of an issue for manufacturers and consumers as the average age of the population increases. Ageing brings with it a range of issues including a loss of strength and reduced dexterity. This paper aimed to look at the relationship between diameter, torque and age for standard consumer closures using a torque-measuring device. The results of the investigation show that larger-diameter jars (85 mm) require much higher opening forces than smaller ones (75 mm and below). Smaller jars require lower opening torques, although the force required to open many jars is still higher than many elderly people are able to generate. Copyright (C) 2009 John Wiley & Sons, Ltd.