Do you buy your water in PET or glass bottles?

Monomere of Polyethylene terephthalate (PET)

For a long time drinks and other liquids were filled in glass bottles. Glass is a very suitable material for this application: it does not release carbon dioxide, it is acid-resistant, it leaves no residue in the liquids and it is relatively easy to process. In contrast, however, it is heavier than the plastic PET (Polyethylene terephthalate) which is used today for beverage bottles. Furthermore it is fragile and more energy is required for the production of bottles.

E.g.  Coca Cola supplied its product of the same name exclusively in glass bottles, until in 1978 ( the company decided to bottle its drinks in plastic (PET) bottles as well.

If one compares the glass and plastic bottles in terms of their environmental impact, one should consider a few other points:

  • resource consumption in production
  • energy expenditure during transport
  • resource and energy consumption for multi-purpose bottles
  • the impact on the climate over the entire life cycle
  • the burden on the environment caused by pollution or careless throwing away

In summary, the returnable PET bottle performs better than a returnable glass bottle. But why?

Due to the lower weight of the plastic, it is more efficient in transport because no beverage crates have to be used. The density of PET is approximately 50% lower than that of glass (density PET: 1.38g/cm³, density glass: 2.5 – 2.6 g/cm³). This also means that a truck can be loaded with more plastic bottles than glass bottles in terms of weight, and the savings in deliveries in turn affect the amount of CO₂ emitted by the truck during transport.

An undeniable advantage of glass is it is 100% recyclable and could be recycled endlessly without loss in quality or purity – theoretically. In practice only 33 percent of waste glass is recycled in America. When you consider 10 million metric tons of glass is disposed of every year in America, that’s not a very high recycling rate. Mostly glass put into the recycling bin is used as a cheap landfill cover to keep costs low.

Glass takes a very, very long time to break down. In fact, it can take a glass bottle one million years to decompose in the environment, possibly even more if it’s in a landfill. Because its life cycle is so long, and because glass doesn’t leach any chemicals, it’s better to repurpose and reuse it over and over again before recycling it.

Due to the lower energy requirement of plastic bottles during production, it also conserves resources. Even with the higher refilling of glass bottles (glass up to 40 times, plastic up to 25 times), however, the advantage of PET bottles cannot be eliminated. Around 500 billion plastic beverage bottles are produced worldwide every year, over 100 billion of them by Coca Cola alone, which is around 190,000 bottles per minute (!). The demand for lightweight packed beverages is not stopping, and the question is: Which packaging to choose?

ALPLA Packaging Report 2019

According to Alpla (a manufacturer of plastic bottles and closures) which published the Alpla Packaging Report 2019, performance of the returnable PET bottle is overall better in the following categories:

  • Climate change [equivalent to kg CO₂]
  • Acidification potential [equivalent to kg SO₂]
  • Summer smog [equivalent to kg Ethylene]
  • Water consumption [liter]

The comparison in these categories of different bottle types (glass and plastic (PET and recycled PET (rPET), one way (OW) and more way (MW)) for mineral water is shown in the charts below.

As expected, the disposable glass bottle shows the worst result with a value of 324 g CO₂ equivalent. The returnable PET bottle with 100% recyclate (rPET) content has the lowest environmental impact.

In acidification, the disposable PET bottle with 100% rPET performs best, followed by the returnable PET bottles. The worst values are again for the glass bottles, with the disposable glass bottle having a significantly higher value than all other bottles.

The comparison with summer smog shows a similar result. All three PET returnable bottles are slightly behind the PET non-returnable bottle with 100% recycled content, followed by the other PET non-returnable bottles, followed by the glass returnable bottle. The value of the non-returnable glass bottle is approximately four times higher than that of the PET bottles.

In terms of water consumption, the PET disposable bottle (< 0.6 liters) is ahead of the PET returnable bottles (0.84 liters), followed by the glass returnable bottle (1 liter) of water per packaging system. The glass non-returnable bottle is again the worst performer with a water consumption of 1.57 liters of water per package.

You can download and read more comparisons about milk, lemonade and detergents as well as these results in detail in the ALPLA report 2019.

Alpla Packaging Report 2019 (c7 consult)


Glass bottles for beverages are still part of our daily use and for water bottling it can be an option when the water source and processing as well as the distribution is not too far away. For longer distant transports, PET based packaging is more resource efficient.

Moreover, glass bottles have still an appearance advantage for beverages such as wine, beer and other alcoholic liquors, which is driven by customers.

Which packaging do you choose? Leave us a comment!

Hopefully we were able to give you some new inputs. Don’t hesitate to share your thoughts and join the hubbub.

Peter & Herwig

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A brief introduction to packaging

In many areas plastics have become indispensable nowadays. Plastics are used in a wide variety of applications and can be individually adapted to the requirements and needs of a certain product. There are tailor-made solutions everywhere, where plastic makes life easier for us. With regard to the impact on the environment, one has to ask oneself whether we want this simplification at all? Can’t we go without plastics in some points or even live without it completely?

With the production of bakelite around 1950, which is regarded as the first “plastic”, apart from resins and similar materials, the production of plastics has strongly increased. In the next graph you can see a comparison of the worldwide production and the European production in million metric tons from 1950 to 2017. As you can see there,  the worldwide demand for plastics and therefore the production is constantly increasing which shows the importance of this material.

If you have data from other continents from this period, we would be very pleased about a message.

Production volume in million metric tons worldwide and in Europe, 1950 – 2017

What is the share of packaging?

Whether in electronics, medicine, mobility, construction or packaging, plastics are used everywhere and above all, packaging requires a large share of the total quantity of plastic produced.The next chart shows the plastics production per industry sector in megatons. Packaging weighs 146 million tonnes, or 35.9% of the total.

Plastic production per industrial sector in megatons in 2017

This is the largest field of application for plastics. The reason for this is that plastics have certain properties suitable for packaging. They have a lower weight than e.g wood or aluminium, are less expensive in production and price per weight, require little volume as packaging material e.g. thin protective films and are also used as barrier material, e.g. to protect and maintain the odour of smelling foods or to keep rapidly spoiling foods fresh for a longer time. In addition, the name, logo, ingredients, content etc. can be printed directly on the packaging films and thus can be directly combined with the protective layer. The multi-functional use of films is described in more detail in the article “potato chips packaging”. The down side of plastic packaging is that it unfortunately often ends up in the environment and pollutes it. Questionable packaging or fake at all?

Unfortunately, the handling of plastics in society is unfortunately still very thoughtless. Particularly people in emerging countries have other priorities in everyday life than the proper collection and recycling of plastics. Whereas the collection and recycling of plastics is part of everyday life in highly developed countries, the challenges here are different: There are examples where packaging probably has a protective function but in many cases its use is very questionable e.g. sweets that are often packaged in several layers, or fruits and vegetables that are individually shrink-wrapped in foil. The authenticity of some of the pictures found on the Internet must be questioned. Anyway, we will take a closer look and question the meaning of these examples. 

Do you know plastic packaging applications which make no sense? Send us a picture, link, or leave us a comment.

In the following articles, some packaging examples will be discussed in more detail and the advantages and disadvantages will be highlighted:

  • Do you buy your water in PET or glass bottles?
  • Why do I need so much food packaging?
  • multilayer filmchocolate bar packaging
  • Life Cycle Assesment (LCA) of plastic bags

Hopefully we were able to give you some new inputs. Don’t hesitate to share your thoughts and join the hubbub.

Peter & Herwig

Stay tuned and sign up for our monthly newsletter.

Plastics, plastics… …everywhere plastics!

If you look around at home, you will probably find a lot of objects made of plastic. Well, this can have positive or negative aspects.

Some of the products take advantage of the properties of plastics such as low density and thus low weight, strengths from elastic to highly rigid, chemical resistance, or low electrical conductivity (insulator), some of them are not produced in a sustainable way and can even influence our health.

Stranded plastic waste mistakenly used as food by birds

In many media, in politics and also partly from many environmental organisations a large concern about the problem of plastic garbage in the environment aroe over the last years.

Well, who wouldn’t stand up and complain about the garbage and all the discarded plastic products that are carelessly thrown away and influence the environment and the species living in it?

I am sure you have heard these stories before, dying birds with their stomach full of plastic or the stranded whale that has swallowed several plastic bags. 90% of the pollution in the world seas come from ten rivers only. Eight of them are in Asia and two in Africa.

Stories about micro-plastics in the food chain rightly led to increased attention to plastic handling, and as already mentioned, various organisations, governments or groups are now launching initiatives, giving tips, creating laws and, above all, discussing how to handle plastics.

Many political projects communicated to the public have a onesided focus on the facts or even have nothing or very little to do with the scientific basis or simple facts. However,especially politicians tend to promote misleading, easy answers to complex questions. People can be won over too easily if you emphasise the downsides and promise a general ban of plastics. However, this view misses the big picture.

There is a need for a more detailed examination which is not so easy for the layman to grasp at first glance. Precise observations and comparisons of individual plastic products and applications show that their environmental impact is less significant than the same products made of other materials.

We would like to show you examples in more detail in the following articles. Some general examples would be:

  • Plastics in mobility for lightweight construction for air or road traffic: heavier vehicles would require more fuel or energy
  • Plastic-free hospitals: Naaah, this would be very questionable from a hygienic point of view and a constant cleaning of used utensils with chemicals would be even more questionable.

That’s why we feed this blog with some examples where it is more eco-friendly to use plastic. Of course with a certain awareness of how to deal with the created litter.

Because one thing is for sure: “There is no plan(et) B”, and we are responsible to handle the resources carefully and keep the impact on nature as small as possible.

Hopefully we were able to give you some new inputs. Don’t hesitate to share your thoughts and join the hubbub.

Peter & Herwig

Stay tuned and sign up for our monthly newsletter.