Glass or Plastic? Which Is More Sustainable?

When we move into the zero-waste or less-waste sector, we quickly come across glass: It looks nicer than the garish packaging that is only meant to entice us to buy the product anyway, it can ideally be stacked wonderfully, is perfectly suited for clean food storage (provided it is tightly sealed) and scores points above all because it can be used again and again and again, thus massively reducing the ecological footprint.

Is glass always more sustainable than plastic?

When you first start researching this topic online, you'll inevitably come across many Instagram-worthy pictures of zero-waste shopping trips in glass containers. And even when you can't make it to the nearest zero-waste shop, you make sure that the packaging of the food you buy is either paper or at least glass – plastic is to be consistently avoided.

This attitude is a bit of an exaggeration, but it pretty much reflects my own behavior. And I think that's (on a whole) a very positive thing – because saving plastic is always a good idea, considering the mountains of waste we as humanity have already produced and continue to grow. To put it cautiously.

But when I began to radically transform our household to a zero-waste lifestyle (the term will likely be discussed separately), I didn't realize that there might also be another perspective: that of food producers.

I am incredibly lucky to have two zero-waste shops ( this one and this one) in my immediate vicinity (even though shopping there does require some planning) , which regularly transport me to a zero-waste paradise: packaging is mostly nonexistent here. Or, alternatively, it's explained in a highly ecological and justifiable way.

Many other people, however, don't have this luxury and have to gradually (and somewhat laboriously) find a network of resources that covers the diverse needs of everyday life, at least to some extent, without using plastic. And that's really not easy – depending on where you live.

And then sometimes you stand in front of the shelves – not just in the supermarket, but also in the organic market – and wonder why on earth everything has to be packaged in plastic. How difficult can it be to switch to more sustainable solutions?

Why isn't there vegan yogurt in (returnable) glass jars? Why is the rice sealed in plastic film? And what's with all the pre-packaged breakfast cereal? Good grief!

I believe these are perfectly legitimate questions. Questions of the kind that should be asked openly (and publicly).

After initially dealing with this privately (at the very beginning in my own brain, later in my circle of friends), I felt compelled to obtain concrete answers (instead of assumptions) to these pressing doubts about common sense.

Specifically, this means that I started questioning brand representatives at trade fairs and other events about this topic. To begin with, I should clarify: grill them . Because as an outraged, sustainability-minded citizen, I felt justified and perceived the industry (even the sustainable ones, or those that consider themselves sustainable) as a completely unreflective mess.

That's obviously not right in that form, I had to learn quickly and get down from my high sustainability horse.

Because although at first glance it may seem that some food companies don't give any thought to resource conservation, carbon footprints, and future generations, that's sometimes only half the story. Namely, the story that's visible from the outside – or that one would like to see.

This by no means implies – and I would like to emphasize this point – that there isn't a massive need for improvement.

This is undeniable – anyone who has ever been to a food fair will know this: the flood of packaging is maximally concentrated there, so that as a person walking through the world with open eyes, you can't help but become aware of this issue.

But it's said that sometimes plastic – as I've discovered in numerous conversations and email exchanges – can indeed be not only the more economical, but also the more ecological solution. At least when producing on a large scale – which is what the well-known brands usually do.

A few reasons for plastic and against glass (from a company perspective)

In the following, I would like to present you with the essence of these many online and offline conversations and list some of the reasons that have been repeatedly given to me regarding the glass-or-plastic question:

Production : Manufacturing glass requires an enormous amount of energy in the form of high temperatures – which then has to be recouped through long-term use. Initially, glass production – like any production – is a negative on the environmental scale. Furthermore, it shouldn't be forgotten that glass is nothing more than concentrated sand – and this raw material (just like petroleum, from which most plastics are derived) is not infinitely available .

Cleaning : Alpro writes to me that, for example, introducing a deposit system for vegan yogurt or plant-based milk alternatives would require a very high level of cleaning effort for each individual jar. This consumes a lot of energy – and above all: water.

Transportation : Generally, the CO2 footprint of glass per gram is lower than that of plastic. The problem: Glass is significantly heavier than plastic. Consequently, transportation consumes more energy. "Specifically, this means that one and the same product can be packaged in, for example, a 300-gram glass container – or in a 20-gram plastic container," Sojade writes to me on the subject.

Storage : Glass is transparent. This means that food may not be adequately protected during storage – vitamins and trace elements can escape and the quality of the product can be impaired.

Recycling : If it is single-use glass (which is mostly the case so far), it has to be melted down again after use – and this usually works at temperatures around 1000ºC, which is also not particularly environmentally friendly and causes a lot of CO2.

The packaging system : All existing facilities for packaging familiar food products are designed to produce items such as Tetra Paks or more or less plastic-dominated cups. A changeover would not only entail considerable costs and enormous logistical effort, but also raise the question: What to do with the decommissioned machines and their parts?

And when exactly is glass sustainable?

The debate about whether glass or plastic is more sustainable is – as we already suspect – once again not a matter of black and white, but rather of gray areas: Glass can be more sustainable than plastic, of course. Specifically, if:

…the transport routes are short. For regional products, it makes perfect sense to package them in glass, which, for example in the case of yogurt or milk jars, can then be cleaned again in cooperation with local businesses that have the necessary equipment. Such local-regional systems already exist to some extent in conventional milk production.

…the packaging is reused repeatedly. From a food technology perspective, this isn't a problem with glass, as glass is inert. This means it doesn't react with other elements and therefore doesn't release any substances into the food it contains – quite unlike plastic , which, depending on the type, can release phthalates, plasticizers, and other potentially hormonally active substances into food. Furthermore, glass – from an industrial perspective – can be recycled up to 30 times. Plastic, at best, ends up in an incinerator and is thus mostly lost as a raw material. Given these massive losses, the recycling of already produced plastic plays an even more crucial role.

…the packaging is large. As with other packaging and containers, the ratio of surface area to contents steadily improves in favor of the contents as the packaging size increases. This means that a few large packages are better than many small ones, even for glass.

Glass or plastic – a distinction must be made.

While the decision regarding packaging and its design is usually obvious to the end consumer (consume as little as possible – no matter what it is), it's not quite so simple for the food industry: products must be transported reliably, protected, and in a reasonably practical and economical way from A to B to C, and the packaging must be designed in such a way that customers are not faced with an unacceptable price at the end.

Understandably, this balancing act is one that may not always be easy – and sometimes not at all.