The twisting force of aged consumers when opening a jar.

Many people experience difficulty when opening a vacuum-sealed jar. Yet solutions to the problem continue to be tool-based rather than exploring the possibility of innovative changes in product packaging. Improvement depends on gaining knowledge of the capabilities of users, and of using that knowledge as a base for product innovation. To establish such a base we took a sample of 750 subjects and asked them two questions about how they opened jars at home. We then carried out torque measurements using a force transducer shaped like a jam jar. We reached the conclusion that if opening torque was reduced to 2 N m then 97.6% of users between 50 and 94 years of age and 100% of 20-30 year old users would have no difficulty opening a jar.