The project aimed to replace the aluminium caps currently used for sparkling‑wine bottles with paper caps, thereby reducing the high energy, water and resource consumption of aluminium production. Aluminium caps weigh about 3 g each, of which roughly 80 % is aluminium (≈2.4 g). Primary aluminium production in 2017 emitted about 1.08 billion tonnes of CO₂‑equivalent, corresponding to 18 t CO₂‑eq per tonne of aluminium. Consequently, a single 3 g aluminium cap generates roughly 43 g CO₂‑eq. In Germany and France alone, Kematec’s bottling lines process more than 1 billion bottles annually, consuming 2 400 t of aluminium and emitting about 43 kt CO₂‑eq each year. The paper‑based process developed in the project eliminates these emissions and offers a more sustainable alternative.

Technically, the new process uses a hybrid backing system: narrow plastic backing plates combined with wide folding plates. The narrow plates create a sharper edge during the initial fold, improving the form stability of the paper cap. Paper, unlike aluminium, has a higher spring‑back tendency; however, pre‑steaming the caps reduces this effect, allowing the folds to retain their shape more reliably. Tests were conducted with caps of varying roll direction, perforation patterns, length and conicity. The combination of the two backing types consistently produced the best folding results, with reduced mis‑folding and improved dimensional accuracy. The project also produced CAD models of the hybrid backings and fabricated 3D‑printed prototypes to validate the design before full‑scale implementation. The final folding quality was judged by visual inspection and dimensional measurements, showing a significant improvement over conventional aluminium caps, which require perforations for ventilation and are prone to mold growth.

The project was funded by the German Federal Environmental Foundation (Deutsche Bundesstiftung Umwelt) under grant number 38475/01‑21. It ran for 18 months, starting on 20 March 2023 and concluding in September 2024. Kematec Kellereitechnik GmbH led the project, with project management handled by Fabian Dages. While the report lists “Kooperationspartner” in the project sheet, specific partner organisations are not named in the provided excerpt; however, the collaboration involved industrial partners and research institutions to develop and test the new cap technology. The project’s outcomes will be disseminated through publications, trade fairs, and direct outreach to existing customers via Kematec’s sales channels. Additionally, test installations will be set up with interested customers to demonstrate the technology under real‑world conditions, supporting market adoption. The successful development of the paper‑cap process gives Kematec a unique selling point and a competitive advantage over international rivals, potentially leading to new revenue streams and a reduced environmental footprint for the sparkling‑wine industry.