Many of us will still remember the days when we used to be able to purchase milk in glass bottles. In fact, that sound of the milk cart powering up the street and the clinking of bottles is synonymous with bygone decades. However, times have changed, and plastic is now the preferred way to store milk.
Despite this, glass milk bottles are experiencing something of a surge in popularity again. There are many reasons for this, from environmental concerns to nostalgia. Which is better? And which is less damaging to the environment? Let's take a look at the advantages and disadvantages of glass milk bottles.
In the not-too-distant past, glass milk bottles almost disappeared. People once relied on bottles of milk delivered daily to their doorstep. At this time, supermarkets had yet to corner the market or require mass milk production to stock their shelves of convenience. Customers also enjoyed the freshest milk possible delivered straight to their door.
However, times change, and so has consumer behavior. In the 1980s, around 90% of the milk consumed in the UK was delivered in glass bottles. Just a few years ago, this stood at 3%. It looked like the doorstep delivery was dead, with the glass milk bottle suffering a similar fate.
There are two reasons for this.
The first is the supermarkets. They have squeezed down prices paid to farmers and manufacturers for years while increasing mass production to satisfy our weekly shops. To ensure they could sell milk as competitively as possible and cheaper to produce3, plastic bottles became the norm. They were also lighter than glass packaging and suffered from fewer breakages, making them perfect for the high volumes of milk sales supermarkets began to enjoy.
The second and related reason is shifting buying habits. As more people shopped at supermarkets for their weekly needs, milk delivery services began to experience less custom. Our busy lives have led to more convenience shopping at all hours of day and night. The idea of always remembering to put out old glass milk bottles and collect fresh ones at a set time each day for many is no longer actually convenient.
Subsequently, many milk delivery services were no longer economically viable. As a result, the UK's then biggest glass milk bottling plant, owned by Dairy Crest, faced closure due to the growing consumer preference for plastic bottles.
Fortunately, in 2015, Müller, a competing dairy company, decided to invest, and with that came growth in Milk & More, a modern milk delivery service where consumers can place their orders online. It has now become the largest milk delivery service in the UK. Further, the service also offers other groceries such as butter and eggs.
A similar service exists in the US called 'Drink Milk in Glass Bottles.' Another example of a service in resurgence that had started to disappear.
Office deliveries have also become a growth area. Due to higher volumes and higher concentrations of offices in any one area, services can deliver milk in glass containers more profitably. As such, today, we can see more office fridges stocked with glass milk bottles.
So whereas most of us still buy our milk in plastic bottles from the supermarket, options for glass bottles still do exist. With this in mind, which variant of milk packaging is best? Are glass bottles better than plastic?
The biggest advantage of glass milk bottles is that they get returned for reuse once we've consumed their contents. Once returned, glass milk bottles are washed, refilled, and sent back out to consumers full of fresh milk. Whereas there are transportation costs and considerations to take into account, avoiding the production of a new plastic bottle for every milk purchase is a win for glass.
When it comes to whether glass or plastic bottles are better we actually have quite a lot to consider. Glass typically takes twice as much energy to produce and, therefore, during production, can actually generate more C02 than plastic when compared by weight.
However, this is just at manufacture, if you average out the additional energy requirements across the lifecycle of a glass milk bottle that gets used again and again, the winner is glass over plastic every time.
The Container Recycling Institute has found that plastic bottles are recycled at a rate of 29%. In comparison to this, glass has a recycling rate of 37%.
Further, as far as plastic goes, there are many vagaries when it comes to recycling4. Different types of plastic waste can vary in their recycling. Whereas most curbside collections do take plastic milk bottles, what happens once collected can vary considerably due to the capacity and ability for them to be processed once collected.
What's more, despite many doing their best, a great deal of the single-use plastic we use ends up in nature. Plastic that enters the sea or landfill will take hundreds of years to break down1. When you consider that 91% of plastic isn't recycled, it has to end up somewhere.
Further, plastic that does get recycled tends to be downgraded into lesser items. For example, you're more likely to find recycled materials from plastic milk bottles in plastic outdoor furniture than in another food-based application. As a result, plastic milk bottles will most likely be "new plastic."
On the other hand, Glass has more of a conscious element to it. Glass breaks easily when thrown away and is heavier, both of which people are aware of. As such, consumers seem more likely to recycle glass bottles than plastic packaging carefully.
Meanwhile, most glass bottles are not sent back for a refill and, at the end of their useful life, are 100% recyclable, and we can recycle them over and over again. What's more, glass has a quick turnaround when it is recycled. Once consumers recycle it, it can be reused again within 30 days.
Better still, recycling glass produces less CO2 emissions and consumes less energy than new plastic2. This is largely down to the polluting resources required to produce new plastic, and that plastic recycling requires more complexity and processing and, accordingly, higher energy use.
When it comes to storing and consuming milk, glass milk bottles are safer. Plastic milk bottles come with a number of risks, including chemical leaching. This means chemicals can leak from the packaging materials into the milk and pose health risks.
Glass milk bottles do not come with the same health concerns. We make glass with natural materials such as sand and limestone. What's more, it is the only packaging that the FDA classes as fully safe.
Due to its natural composition, glass is chemically inert. This means that it does not consist of reactive chemicals.
Let's face it, consumers love simplicity. Plastic milk bottles can leak from the lid when squeezed. We've probably all suffered a leaky plastic bottle from time to time.
Whereas a glass bottle retains the same shape and won't leak when crushed at the bottom of a supermarket bag under heavier items. Glass products are also more robust and sturdy to hold, of course, you do need to keep them upright.
We all know just how flexible plastic bottles are. While glass is undoubtedly strong and has the ability to safely store content, it is also fragile. Any kind of impact can cause the glass to break, which instantly means that it is useless. What's more, it means that the contents will also go to waste.
Glass is also susceptible to sharp changes in temperature. Therefore, a glass milk bottle left on a doorstep can shatter once it is met with warm temperatures.
When we compared to the thin plastic milk bottles we have become accustomed to, there is no doubt glass is heavier. As a result, its weight adds to the cost of transportation. Also, it means that consumers will have to the price as well as the environment due to the emissions from transporting the bottles.
In this respect, alternative containers such as cardboard or even plastic are a more favorable option. In some instances, manufacturers have attempted to use thinner glass. However, this brings with it a range of other issues.
A simple accident can cause the glass to shatter into sharp shards and break. This makes it more dangerous than plastic. With shattered glass comes the risk of cuts, and what's more, the broken pieces can also find their way into other bottles if damaged during the manufacturing process.
At any time during the entire process, from manufacturing bottles to filling them to transporting them and even handling by consumers, the glass can pose a safety risk.
Of course, having a milk delivery will ensure that the milk is as fresh as possible. However, traditional glass milk bottles come with foil tops. Exposure to air can reduce the shelf life of milk once a seal gets broken and contribute to food waste. Plastic bottles can come with lids that we can re-seal. This ensures the milk can remain as fresh as possible.
It is possible to put lids on glass bottles. However, this would require the use of other materials, and that can have a cost implication as well as an implication on the environment if the lid is made of plastic.
Further, the wholly transparent nature of most glass milk bottles can degrade milk when exposed to light. The slightly translucent plastic alternatives offer a slight advantage here. Of course, it's not too much of a problem as most of us safely store our milk in the dark of the refrigerator.
With the advantages and disadvantages clear to see, we have asked whether glass is a feasible option for transporting and storing milk?
The environmental advantages outweigh the disadvantages, which is certainly a positive thing. What's more, the resurgence in the use of glass milk bottles proves that people are now thinking and buying in a more environmentally conscious way.
More and more of us no longer want to purchase milk in plastic bottles. As we increasingly look to alternatives to plastic, we're likely to see more glass used. Therefore, it should only be seen as a good thing that glass milk bottles are making a comeback.
All the same, until supermarkets can find a way to produce, transport, and reuse glass milk bottles cost-effectively, plastic will continue to be their de facto choice and fill the dairy aisle. The more of us that switch to glass, the more likely it is they'll look to proactively move away from plastic.
From being kinder to the environment to reducing plastic waste and even being kinder to our bodies, glass bottles seem to be a better choice all around.
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|W. Mack, "Recycling Plastics: The Problems and Potential Solutions," in Disposal of Plastics with Minimum Environmental Impact, ed. H. Mackinney (West Conshohocken, PA: ASTM International, 1973), 3-16. https://doi.org/10.1520/STP38581S|