The prototype is made by a Danish company from an extra-strong paper shell that still contains a thin plastic liner.
But the goal is to create a 100% recyclable, plastic-free bottle capable of preventing gas escaping from carbonated drinks.
The barrier must also ensure no fibres flake off into the liquid.
That would pose a risk of altering the taste of the drink – or potentially fall foul of health and safety checks.
But industry giants are backing the plan. Coca-Cola, for example, has set a goal of producing zero waste by 2030