Even the best parties come to an end. The last remnants of the cake have gone into the fridge. The next morning, the big clean-up begins. The empty beer bottles go back into the crate, and the next time you go to the supermarket they go into the deposit machine. The wine bottles find their (temporary) end in the bottle bank, where you can also take the jam jar you emptied at breakfast.
Glass packaging has a sustainable reputation, so there's no need to feel guilty when disposing of the party leftovers - especially when it comes to alcohol consumption or the sweet attack that was warded off with an empty jar of hazelnut cream. But is glass packaging really more environmentally friendly?
Long shelf life
The production of new glass containers, whether for drinks or yoghurt in a jar, is certainly very energy and resource intensive. In particular, the enormous temperatures at which glass has to be melted down result in a high CO2 footprint.
Glass bottles therefore have the potential to be a sustainable alternative, especially if they are reusable and do not have to be produced anew each time. Manufacturers can refill returnable bottles up to 50 times, giving them a lifespan of up to 6 years. By comparison, this is only possible half as often with reusable plastic bottles.
In addition, glass is inert, meaning it does not release any flavour or odour into the packaged product - whereas plastic can release substances such as plasticisers, which are highly undesirable in food. Glass as a packaging material can certainly meet the demands of customers in terms of sustainability and food safety. "In all our studies and those of institutes, glass packaging is regularly very favourably received by end consumers. Reusable packaging generally tops this result, regardless of the material. The starting position is therefore ideal for looking at glass as a packaging material," says Pacoon Managing Director Peter Désilets.
Reusable with stumbling blocks
However, the German deposit system has its pitfalls and, in the worst case, more resources are consumed than saved. For one thing, the reusable system only applies to certain glasses in Germany. Michael Heidan, Managing Director of ReViSalt, has been working in the glass industry for years: "There are only a few countries in the world where deposit systems for glass exist at all. In Germany, there are deposit systems, but only for a manageable number of glass types. A lot is melted down or thrown away."
The glass bottles in beer crates are reused, but the situation is different for wine - but the first pilots are emerging here, as reusable wine used to be the standard route with regional rinsing centres for winegrowers. This is to be revitalised. However, many glass containers usually end up in the glass container, just like a jar of gherkins, for example. According to Heidan, reusable is a "theoretical ideal that does not yet exist sufficiently in reality".
No standard glass
On the other hand, bottles end up in deposit machines that do not meet uniform standards. Manufacturers want to stand out from the market, for example by filling beer in bottles with different shapes, so-called "customised bottles". These are then, of course, to be sold throughout Germany, delivered from Bavaria to northern Germany or even abroad - often with lighter bottles, as it is currently unlikely that they will be returned.
Once the beverages made from hops and malt have been drunk, the empty glass bottles have to be returned to their original production site, together with their branded crates. The washing system is installed there and can clean and refill the bottles. This means unnecessarily long journeys for the return transport, which cancels out some of the advantages of the returnable system. "But despite this disadvantage, reusable usually pays for itself after two to five rounds compared to disposable. And there is still a lot of potential for optimisation. We can already make glass around 50 per cent lighter and at the same time more stable. We have also developed a new reusable concept that saves over 20 per cent when bottles and crates are filled and over 50 per cent when empty. If these bottles or containers are then standardised, the cleaning centres take over the cleaning regionally and deliver rinsed containers for filling, then the use also pays off for small bottlers. If the containers are then rented out instead of having to be bought, then the battle for the containers, which the small ones usually lose and have to buy new containers at a high price, will also end. That would be the democratisation of reusable containers," says Peter Désilets about the prospects for glass packaging.
Recycling as plan B
On the other hand, there are standardised bottles, so-called "pool bottles", with a uniform shape. They can be cleaned and refilled at the nearest bottling plant. "The deposit system is right and proper and ultimately really makes sense if there are uniform standards," says Heidan. "It's always about wasting resources and sustainability. The effort involved in transport, logistics and sorting is huge, but it doesn't really make much sense to only use glass once. The higher the circulation rate, the more environmentally friendly the returnable glass becomes."
Nevertheless, the advantages of glass are also evident in single-use packaging, especially when it comes to recycling. "Unlike plastic, glass can be recycled indefinitely and does not lose any of its properties," explains Heidan. Melting down and producing new bottles still costs a lot of energy, but using used glass at least reduces the amount of new materials required. The trip to the glass container and separation by colour is therefore not in vain.
Development needed
According to Heidan, another point is saving material: "The most important thing with glass is to make it thinner and lighter, as this directly saves energy and resources." At the same time, the glass must be resistant. Expensive products such as smartphone displays are already chemically strengthened in a lengthy and cost-intensive process, making them significantly more robust. ReViSalt has developed a process that enables chemical hardening in minutes instead of hours. This makes chemically tempered glass attractive for the mass market and therefore also for the packaging industry.
However, like many other sectors, the glass industry is cautious; after all, extensive production changes also mean investment. It will probably be some time before bottles are standardised and become lighter and more resistant thanks to technical innovations. It would be important to push for such a development today - whether on the part of legislators or companies that will have to modernise an outdated production site in the future anyway. Peter Désilets: "Future-oriented companies should see this approach as a lucrative business model - a new technology with 50 per cent less material means a head start over competitors, significantly lower CO2 output and lower compensation payments and costs in the future, and therefore new growth opportunities. If companies see this approach less as the production of tonnage and more as value creation, then the future looks bright.
This also applies to the decision to use glass as a packaging material in the first place. While milk in a glass bottle or yoghurt in a jar have so far been the exception rather than the rule, beer and wine have been available in glass packaging for a long time. "Traditionally, there are foods that consumers can better imagine in glass - these include beer and wine. With other foods, however, there is also a fear of breakage, broken glass and food waste. However, this can still be reduced with the new, shatterproof glass technologies - although the actual breakage rates are much lower than is generally feared," says Désilets.
Food packaged sustainably?
Those who buy drinks and food in glass packaging instead of plastic often believe that they have contributed to solving the waste problem. But as we have seen, there is great potential for glass to become even more sustainable.
Expanding the reusable system and setting uniform standards is part of this. Lemonade and mineral water are also increasingly being bottled in reusable glass bottles. Manufacturers have recognised the sustainable benefits and customer demand. But transporting empties halfway across the country is not very environmentally friendly. For glass to live up to its sustainable image, the framework conditions must be right. Peter Désilets explains what these are: "The most important lever towards reusability is the establishment of an international recycling system with take-back, sorting, cleaning, distribution and tracking. This system is emerging, but is currently still being driven by small initiatives. The EU and other countries and regions around the world should focus their investments here, as take-back centres need to be created. Consumers need to be able to return products easily, which is always a sticking point for a high level of acceptance."