Austria's beer drinkers have a special quirk: they use glass bottles disproportionately often. At Brau Union, the country's largest brewery company, returnable glass bottles make up almost half of the packaging mix. The classic beer bottle can be refilled around 40 times before it has to be recycled. From the consumer's point of view, one aspect in particular speaks against the bottles: they are relatively heavy.
Reusable bottles are becoming lighter, harder and transport-optimised
When packaging giant Vetropack launched a new bottle on the market together with Brau Union in 2024, its weight was one of the main arguments. The 0.33-litre bottle is thermally hardened using an innovative process, which makes it 210 grams, around a third lighter than conventional glass bottles. At the same time, it is more resistant - Vetropack estimates that the bottle can handle around 20 per cent more rotations.
And a third aspect was part of the design considerations. Together with several partners, Vetropack has developed a bottle and crate mould that allows more rows of crates on a pallet. This has a direct impact on transport costs.
The small beer bottle addresses two of the most important arguments against reusable glass bottles: the comparatively high weight and the transport routes for re-filling, which cause considerable CO2 emissions.
Reusable and disposable have different potentials
"These are just a few examples of where there is still a lot of potential to significantly optimise existing processes and products that have been used for decades," says Peter Désilets, Managing Director of Pacoon. "And we're not talking about small subtleties, but about major optimisations that will advance the entire reusable system. That's the big difference to single-use packaging, which essentially lives from rather marginal advances that are very much centred around end-of-life and recycling."
PET or glass? Reusable or disposable? Life cycle assessment in transition
In 2023, the Heidelberg Institute for Energy and Environmental Research (ifeu) conducted a comprehensive extensive study the life cycle assessments of non-returnable PET bottles and returnable PET and glass bottles. The 1.5-litre disposable PET bottles in particular showed advantages over the other two types of packaging.
However, the seemingly clear result for the environmental balance is subject to limitations. On the one hand, the study states: "The calculated single-use PET system is always dependent on input of new material or recycled material from outside for operation." At the same time, the study authors themselves point out that the "mapping of reusable bottles (...) was based on an updated extrapolation of older study results (GDB 2008 and IK 2010)". "Possible optimisation potentials within the reusable systems are not the subject of the study."
However, it is precisely this optimisation potential that Peter Désilets considers to be criminally underestimated. "Today, we can also see in other areas of reusable packaging how the levers of sustainability can be optimised through lighter but stable plastic packaging through to very durable materials for many cycles. We ourselves are working on more durable jars that are also nestable thanks to a special hardening process. The crate has also been completely redesigned and, in conjunction with the jars, allows the empty crates to be nested - saving up to 40 per cent space on the pallet. And finally, we want to tackle the issue of reusable lids, which has not yet been addressed."
Production processes are causing a furore
The breakthrough that Chinese researchers recently achieved, according to their own statements, shows just how disruptive developments can be, even in processes that are considered to be exhausted. Their new "flash ironmaking" method is said to make it possible to extract pure iron from iron ore in just a few seconds - a process that previously took around five to six hours. The saving in energy and time is therefore around 3,600 per cent.
Research at the Max Planck Institute for Sustainable Materials is going in a similar direction: a design study shows how the extraction, production, mixing and processing of metals can be combined in a single step. The method has an energy-saving potential of 40 per cent, and the use of hydrogen instead of coal would reduce CO2 emissions to zero.
Reusable glass bottles: new methods open doors
Are there similarly spectacular breakthroughs in glass production? In 2023, packaging manufacturer Ardagh Group commissioned the NextGen furnace at its plant in Obernkirchen, Lower Saxony. Previously, around 90 per cent of the process heat for the amber glass bottles produced here was based on gas and ten per cent on electricity. Today, it is almost the other way round: up to 80 per cent of the melting energy comes from electrodes -- which are fed from renewable energy sources - and only 20 per cent from flame radiation. The result: the plant saves around 45,000 tonnes of carbon emissions every year. At the same time, the proportion of recycled glass used has risen to around 70 per cent.
The Saxon start-up ReViSalt has invented a special method of glass tempering: They took up a long-forgotten method from GDR times and developed it further into "rapid chemical hardening". This also involves enormous process acceleration. In contrast to the established thermal solidification process, it now only takes 30 minutes instead of 24 hours - with the difference that the process also works with very thin-walled glass. The method makes it possible to make almost any glass product thinner, lighter and more resistant to breakage and scratching. And with significantly less material and energy input.
"So if it is possible to use less glass and make it last longer by skinning it, as well as significantly reducing energy consumption and CO2 emissions in production, then this dramatically improves the initial situation of the containers," emphasises Peter Désilets.
Together with better transport logistics in pallet utilisation and weight reduction, the comparisons between disposable and reusable containers would have to be completely recalculated. "We are also looking at segments with disposable jars or more stable plastic containers for sauces and spreads, jams and preserves. Even in the initial situation, the ratio looks much better than with one-way deposits for bottles."
The breakthrough also involves transport routes and logistics
What is common practice for beer bottles has never caught on for wine for various reasons. In the wine segment, the path is back to reuse. What used to be the practice of taking an empty bottle back to the winemaker of your choice and refilling the cellar is now increasingly reflected in the spread of reusable bottles. This is intended to revive the regional rinsing centres that used to be common. These have become unprofitable due to the increase in individual bottles. Reusable glass bottles made from special lightweight glass that can be refilled up to 50 times should then help to reduce transport emissions.
Decentralised rinsing logistics also address one of the main obstacles standing in the way of reusable containers: No matter how light and break-resistant the glass packaging is, the cycle of return, cleaning and redelivery is neither particularly highly automated nor widely rolled out. Many bottlers wash their own bottles, and the service provided by independent third parties must first be expanded to make it easier for small bottlers to use reusable containers. In the course of this, rental containers will also make small quantities profitable. Reusable plastic containers are also suffering from the same restriction, as the mass argument is not convincing.
Peter Désilets expects decisive steps to be taken here too: the more reusable glass or plastic containers are serialised, the simpler the corresponding cycles will become - and therefore also more cost-effective. His vision: the combination of harmonised containers and regional rinsing centres will make it possible to distribute empties in the region and thus massively reduce transport routes and emissions. The possibility of regional transport would have another major ecological advantage: step by step, e-mobility could also find its way into these cycles and thus prevent further huge amounts of emissions.
For Peter Désilets, the conclusion is clear: "Reusable solutions generally promise a significant reduction in the amount of packaging and packaging waste, as the PPWR aims to achieve. However, the rather weak reusable targets could indirectly lead to much higher reusable rates. Either because it is unprofitable to operate two systems and manufacturers are therefore more willing to - forcibly - establish reusable packaging and phase out single-use packaging. Or because other countries, such as France, are even more demanding in their national legislation, systems develop more quickly and then become significantly more profitable - and when it comes to savings, many manufacturers become 'soft' on solid reusable containers. Not forgetting ecofees and ultimately image factors."
Pacoon will soon be chemically hardening its glass containers to see how much glass can be saved and how the containers behave in reusable packaging. "For 2026, we are aiming for a market test for sauces, jams, spreads and preserves. Maybe we can debunk some other myths and provide more investment security."
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