Potential, Limitations and Myths of Reusable Glass Packaging

Organic food retailer Alnatura has been conducting systematic packaging work since 2013 and has extensive experience with glass reuse solutions. We spoke with Isabell Kuhl, Head of Sustainable Quality at Alnatura, about the advantages, potential and limitations of reusable glass, about perceived versus actual sustainability, glass myths amongst customers, and where single-use solutions still have their place.

Various softdrinks in returnable bottles — Long-established reusable systems are a fixed component of Alnatura's beverage range.

How do Alnatura's overarching packaging objectives look and how does reuse fit into this?

We have a very holistic understanding of sustainability, which is why we've been working systematically on our packaging since 2013. Since 2020, we've had clearly formulated goals: we want to use packaging as much as necessary but as little as possible, reuse it multiple times wherever feasible, and fundamentally think in circular terms. So reuse is absolutely central and at the same time our biggest challenge.

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Isabell Kuhl, Head of Sustainable Quality at Alnatura

Where do the challenges lie? Aren't glass and reuse a "no-brainer" in organic retail?

You definitely have to look closely and differentiate. With packaging, there's still a big gap between perceived and actual sustainability. This applies specifically to glass as a packaging material, particularly when you don't distinguish between single-use and reusable options.

We were a practice partner in a research project by the institutes ifeu - Institute for Energy and Environmental Research Heidelberg and IÖW Institute for Ecological Economic Research. Using passata as an example, we examined the packaging alternatives of single-use glass, reusable deposit glass and single-use composite carton, and for almonds we investigated the alternatives of reusable deposit glass, single-use plastic pouches and Unpacked.

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With the passata, it became clear that single-use glass isn't a sustainable solution because the high energy requirements of glass production can't be compensated by single use. Reusable deposit glass is different. Glass is simply a very high-quality material that's well suited to multiple use. I don't throw away my drinking glass after every use either. The composite carton proved to be an ecologically optimised single-use packaging.

For the dry bulk goods of almonds, the most sustainable solution turned out to be filling the nuts into customers' own containers or provided reusable cups. Thin plastic pouches achieved the second-best result. Reusable deposit glass, however, wasn't a sustainable alternative. The single-use metal lid of the reusable glass alone destroys the balance sheet because it's much heavier and more resource-intensive than the lightweight pouch.

The ideal path we've formulated for ourselves is: if glass, then as a reusable variant and as a replacement for heavy single-use packaging.

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Food products in returnable glass containers on a shelf in a supermarket — Examples of cross-utilisation of reusable glasses as known from dairy products.

Where does Alnatura use reusable glass and where are the limits?

Long-established reusable systems that are well known amongst organic customers, work well and don't need to be questioned, can be found with beverages and dairy products. Of course, empty container logistics is always a challenge with reusables. You have to factor this in, for example when it comes to space requirements in stores or the increased workload for staff. Therefore, the fundamentally positive statement initially only applies to our 150+ own stores. We also have trading partners domestically with different infrastructural requirements and international trading partners in 18 countries with 15,000 branches where unfortunately there are no corresponding return systems.

Another disadvantage with some established reusable glass packaging is the low deposit, which often has nothing to do with the actual value of the packaging. Here, one could certainly increase the incentive for returns.

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Where reusable glass can literally reach its limits is regarding transport distances. If we source tomato sauce from Italy, for example, it's very questionable whether it's sustainable to transport the empties back over these great distances. And finally, baby food is also a reusable glass no-go for us. Not everyone uses the recommended plastic spoons, and metal spoons can repeatedly cause micro-damage to the glass and eventually lead to glass breakage. No product manufacturer or retailer wants that kind of recall. So you stick with the single-use solution.

Can established reusable systems be cross-utilised for other products, and are there new areas of application?

We've been experimenting since 2019 together with partners to see whether and how established reusable containers can be used for other products. The results are mixed. The size and shape of established reusable glass packaging are often not optimal for other products. Different fill sizes lead to different prices that appear higher at first glance. Added to this, product manufacturers often don't have washing logistics or their logistics are optimised for single-use. Residual emptying is also often not optimal with established reusable glass formats, for example in the case of creams. And finally, there's the already mentioned limitation that glass isn't sustainable for lightweight dry products even as a reusable solution. But we're staying with the cross-utilisation topic because whilst it's challenging, it's simultaneously low-threshold.

We've had new, positive experiences with a reusable glass system for oils. We use the dotch bottle there, which also won the German Packaging Award in 2024. This reusable bottle was specifically designed for oils, so the shape and size fit. It's also advantageous that dotch isn't just a bottle supplier but also offers transport and washing logistics. What remains is some communication effort towards customers for whom reuse is new in this segment.

Author: Christian Nink, Freelance Journalist

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Potential, Limitations and Myths of Reusable Glass Packaging

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