In 1907, a Belgium chemist named Leo Baekeland invented the first fully synthetic plastic and forever changed the world.
The potential of plastic inspired subsequent technological innovations and progressions in almost every sector. An area within the coffee industry that was particularly revolutionised by the use of plastic is packaging.
Packaging plays a critical role in preserving the freshness and quality of coffee beans. It protects them from elements that would hasten their degradation. However, that protection only lasts as long as the packaging remains sealed.
At least until the advent of resealable packaging. Tin ties and zippers have become two of the most affordable, accessible, and easy-to-use ways for roasters to seal coffee bags or pouches.
That said, one century later, society has found itself in the position of having to weigh the continued use of plastic packaging against its detrimental environmental impact. Around 36% of all plastic produced is used to create packaging, 85% of which ends up in landfills.
This has led many within the coffee industry to question whether resealable zippers in coffee bags are recyclable and if there are more sustainable alternatives.
Why do coffee bags have resealable zippers?
Resealable bags, now more colloquially known as zip-lock bags, were first invented in the 1950s by a Danish inventor named Borge Madsen.
Madsen then sold the patent for the design to Max and Edgar Ausnit, who created the company Flexigrip and began manufacturing “resealable” bags that featured a plastic zipper.
That said, the brothers refined the design and manufacturing process to make the bags easier to use and cheaper to produce.
Early designs of the bags and zippers required a small piece of plastic, which had to be slid from one end to the other in order to seal the bag. It is Max’s son, Steven, who is credited with designing the zippers commonly used today.
He thought of making this mechanism because the manufacturing the former version of the Ziploc bags was quite expensive. The new zip-lock bags were manufactured in two parts: the press to seal section and the plastic bag.
The product experienced massive success and has become as ubiquitous as the problem it addresses: maintaining the freshness of food. Or, in this case, coffee.
Once coffee packaging is open, the deterioration of the product will accelerate owing to exposure to moisture and oxygen.
Additionally, the loss of volatile compounds in the coffee and oxidation will have a noticeable effect on the quality within a few hours of exposure.
And so, born of necessity, resealable bags offer consumers the convenience of preserving the freshness of the coffee without having to transfer the beans or ground coffee into another container.
How are resealable zippers made?
The original design of zip-lock bags required the zipper to be heat-sealed onto the bag, which was time-consuming and costly.
However, in 1962, Ausnit learned of a Japanese company called Seisan Nihon Sha, which had discovered a way to incorporate the zipper into the bag itself. This process increased the functionality of the design and reduced the cost of manufacturing.
With the new design, a new company was formed, and by 1973, resealable bags had become an indispensable item for the home.
Coffee packaging differs slightly, as the resealable zipper is usually added to the packaging after the bag is made, as per client specification.
Opposing strips are heat stamped onto different sides of the coffee bag at the opening. One side has a channel, while the other side has a ridge. When pressed together, they lock into place, creating an airtight environment.
Resealable bags are highly effective in situations that require the bag to be accessed multiple times.
For example, if a roaster is emptying a 1kg bag of beans into the hopper of a grinder, the resealable zipper may have limited benefits.
That said, many roasters tend to package their coffee offerings in smaller bags, usually the same size as retail coffee.
Whether this is for home use or wholesale, being able to re-seal the bags in between uses is essential. Therefore, it is common for filter and retail coffee bags to come with a resealable zipper.
As people become increasingly aware of the environmental impact of their purchasing habits, it’s important for specialty coffee roasters to take measures to reduce their waste wherever they can.
Using coffee bags and pouches with resealable zippers is an effective and inexpensive way of doing this.
Can resealable zippers in coffee bags be recycled?
The majority of resealable zippers used in coffee packaging are usually made from low-density polyethylene (LDPE) or polylactic acid (PLA).
The use of these materials can cause confusion among consumers, as each must be disposed of in different ways.
For example, if the coffee bag is made of a different material than that of the zipper, it may have to be separated from the packaging before recycling.
Understanding the materials and terminology regarding coffee packaging requires due diligence, and it is essential roasters convey this information to consumers.
For instance, recyclable materials can be broken down and made into something else. For these items to be recycled, they must be disposed of correctly.
If a non-recyclable item contaminates a batch at the recycling plant, it may lead to the entire lot ending up in landfill.
Biodegradable plastics or bioplastics, such as PLA break down naturally over time. PLA is classified as a 100% bio-sourced plastic: it is made using renewable resources such as corn and sugar cane.
Lactic acid, obtained by fermenting sugar or starch, is then transformed into a monomer called lactide. This lactide is then polymerised to produce PLA.
It is important to note that some PLA can only be composted in industrial facilities as it requires specific oxygen levels and temperatures of 60°C (140°F).
That said, some companies now introduce an enzyme which acts as a catalyst that hastens the bioplastic’s disintegration, making it suitable for home composting.
While biodegradable and compostable materials are similar, they require different conditions in order to break down.
For instance, compostable items are made from materials that can break down into water, carbon dioxide, and biomass (renewable energy) under the right set of conditions. Often, it requires a controlled environment, such as a constant minimum temperature, to break down efficiently.
When it comes to sustainability, the more probing question is not, can it be recycled, but does it get recycled?
If the bag and the resealable zipper need to be separated before they can be composted or recycled, it leaves a lot up to the end user.
That is why the team at MTPak ensures all the materials used in our packaging are compatible and can be recycled together.
We can help you decide on the best resealing option for your coffee bags, from pocket and loop zippers, to tear notches and zip locks. All our resealable features can be integrated into our recyclable, compostable, and biodegradable coffee bags.
Plus, we are able to custom-print coffee bags using innovative digital printing technology, with a quick turnaround time of 40-hours and 24-hour shipping time.
MTPak Coffee also offers low minimum order quantities (MOQs) to micro-roasters who are looking to remain agile while showcasing brand identity and a commitment to the environment.