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Against the background that beverage containers and their caps regularly head the top 10 list of single-use plastic items found on beaches, the European Union has issued Directive 2019/904/EU on the reduction of the impact of certain plastic products on the environment.  

This so-called Single-Use Plastics Directive stipulates, among other things, that plastic beverage containers with a capacity of up to three liters may only be placed on the European market from the 3rd of July 2024, if their plastic caps remain attached to the beverage container. 

In germany, some companies had already introduced tethered caps before the directive came into force. This resulted in a multitude of, more or less user-friendly tethered cap solutions on the market, even before the directive came into force.  

The few publicly available studies on the usability and consumer acceptance of tethered caps published so far are of limited informative value in this context because of their study design, especially with regards to children, elderly people and people with physical impairment. 

Objectives of the study 

Against this background, the DIN Consumer Council commissioned a study in order to… 

• obtain detailed feedback from consumers on the usability and acceptance of tethered caps for beverage containers,  
• identify possible design optimizations,  
• evaluate the optimizations suggested by the consumers surveyed with regards to the technical feasibility with packaging experts,  
• to derive recommendations for standardization. 

Methodical approach 

As part of the qualitative study in total 30 consumers, amongst them 6 children aged between six and nine years, 6 consumers without special limitations and 6 consumers with manual impairments (e.g. rheumatoid arthritis), 6 with age-related limitations (i.e. consumers aged 70+) and 6 with visual impairments (e.g. astigmatism) were interviewed.  

Although each of the tethered cap systems tested (Snap Cap, Clip Aside/Hinge Cap, Twist Cap, Sport Cap, Lasso Cap, Heli Cap) had individual advantages and disadvantages, none of the systems were able to fully convince the consumers surveyed. 

In particular, the children and elderly and/or physically impaired people interviewed as part of the study encountered major problems when using disposable drinks containers with tethered caps, ranging from increased effort necessary for opening/closing, spills and injuries to complete inability of the study participants to open the bottles and beverage containers. 

In addition, it was also shown that the relationship between the stability of the beverage container, the position and texture of the cap and the force required to open it is of essential importance for the usability of the beverage containers and thus for consumer satisfaction with the packaging. 

Key findings of the study 

• The consumers interviewed for the study generally felt they hadn’t been informed well enough about the introduction of the tethered caps. 
• The interviewed consumers saw little environmental benefit arising from the tethered caps; a perception which further negatively impacts consumer acceptance of tethered cap solutions. 
• The consumers interviewed complained about the confusing number of tethered cap solutions available. Having too many different systems in use is overwhelming in day-to-day use and requires the continuous adaptation of subconscious action sequences. 
• The interviewed consumers were dissatisfied with the usability of the tethered cap solutions that are currently on the market. Opening and closing of the tethered caps, as well as pouring or drinking out of single-use beverage containers/bottles with tethered caps is found to be considerably more difficult than was the case with bottles where the cap could be removed completely. 

What are the next steps?  

The DIN Consumer Council is currently working with relevant stakeholders to determine how the findings of the study and the recommendations derived from them can best be implemented in regulatory and manufacturing practice as well as in standardization. 

The study is available for free download here: https://www.din.de/de/ueber-normen-und-standards/nutzen-fuer-den-verbraucher/verbraucherrat/ueber-uns/studie-kunststoffverschluesse-1191002  

Would you like to give us consumer-relevant input on the topic of “tethered caps” and/or would you like to discuss the above topic with us? Then please do not hesitate to contact the DIN Consumer Council (stefanie.scholz@din.de). We look forward to exchanging ideas with you!