How durable are compostable coffee bags?

Jane Merchant
May 12, 2022
How durable are compostable coffee bags?

A growing number of businesses are investing in sustainable packaging options as governments increase restrictions on non-recyclable plastics. 

A large percentage of these investments focus on compostable packaging materials, such as those made from polylactic acid (PLA). These compostable plastics are made using renewable materials like maize, cornstarch, and sugarcane.

Studies have revealed compostable materials are better for the planet, as they produce fewer greenhouse gases during decomposition. As a result, many roasters are choosing to use compostable coffee bags.

That said, some have their concerns about the durability of compostable packaging. However, by using these materials in multilayer packaging, roasters can ensure their coffee is perfectly preserved and well protected. 

Read on to find out more about the durability of compostable coffee bags.

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White rice paper compostable coffee pouch with white label on brown background.

What are compostable coffee bags?

Traditional plastics are made from petrochemicals. These are refined and heated into ethane and propane and combined to create polymers.

These polymers are formed into plastic pellets, which businesses then melt and mould into everything from packets to bottles. However, when traditional plastics are recycled, they tend to degrade and are costly to repurpose. 

As a result, new plastics are made, which contribute to the global plastic waste crisis. When plastic waste is not accumulating in landfills, it is often incinerated, releasing harmful emissions into the atmosphere.

Plastic may also end up polluting water sources, killing fauna and flora before eventually being consumed by humans as microplastics.

To address this issue, compostable plastic bags were produced. Unlike traditional plastics, these are made using renewable materials such as plant starches.

When disposed of, they break down into carbon dioxide (CO2), water, and biomass  – without producing harmful emissions or byproducts. 

One of the most common compostable plastics is polylactic acid (PLA), which is often made from cornstarch. It uses 52% less energy to create and produces 80% fewer emissions than traditional plastics.

Most commercially produced PLA packaging is industrially compostable. This means it will not disintegrate unless composted in specific, temperature-controlled facilities. As a result, PLA is unlikely to degrade in a standard garden environment.

Caucasian male coffee roasters holding white compostable multilayer coffee pouches with brown sacks of coffee in background.

How durable are compostable coffee bags? 

When people hear the word compostable, they often think of home composting heaps. This is where kitchen scraps are placed to break down, making the soil richer and more nutritious. 

As PLA and other bioplastics are technically compostable, it is common for customers to assume they will break down the same way.

However, the majority of compostable plastics are much hardier. Most PLA packaging will decompose into CO2 and water in 90 days in a controlled environment. 

That said, this process could also take up to a year, as the rate of decomposition depends on various environmental factors. These include temperature and humidity, as well as pH, oxygen, and water acidity levels, to name a few. 

Under normal conditions, PLA is not readily biodegradable or hydrosoluble. Its ability to degrade is affected by several factors, including time, the material’s weight, and how much of the material’s surface area is exposed to the environment.

Additionally, some forms of PLA can only degrade in the presence of certain microorganisms.

Dark roasted coffee beans in plastic tub next to compostable unbleached kraft paper coffee pouch.

What to consider when choosing compostable coffee packaging

As a packaging material, PLA is as strong as plastic. It has effective thermoplasticity and processability, which makes it easy to mould into different shapes. However, at temperatures exceeding 180°C (356°F), PLA can become unstable.

To prevent it from weakening prematurely or while in use, manufacturers can add organic modifiers and stabilisers to lengthen and strengthen its polymer chains. Some also have nanoparticles or nano reinforcements added to improve their mechanical properties. 

PLA has certain qualities that make it well suited to packaging coffee. To preserve its lifespan before and during use, PLA packaging must be stored in cool, dry conditions to prevent warping or degradation. Roasted coffee must also be stored in similar conditions. 

Furthermore, as roasted whole bean and ground coffee is often sold in smaller volumes, PLA packaging will have less time to degrade. ‘

Ultimately, PLA may not be as strong or durable as traditional plastic. However, when it comes to packaging a dry goods product with a reduced shelf life like coffee, it is highly effective. 

Important to note is roasters will have to instruct customers on how to dispose of used PLA packaging correctly. This includes informing customers on whether they need to remove the degassing valve or interior lining.

If not disposed of correctly, PLA packaging may contaminate batches of recyclable material, or end up in landfills where they will degrade as slowly as plastics. Therefore, it can only be placed in certain bins. 

If these bins are not easily accessible, roasters can encourage customers to return empty coffee packaging. It can then be sent back to its manufacturer for proper recycling. 

With an estimated 8 million tons of plastic waste finding its way into our oceans every year, it is no wonder expectations towards sustainability are changing. Notably, a recent survey revealed 61% of customers consciously limited their purchases of single-use plastic in 2021.

As a roaster or coffee shop owner, it is vital to keep up with growing customer expectations and consider the environmental impact of your business. Making the switch to compostable coffee bags and PLA packaging can be the first step.

White multilayer coffee pouch on counter next to black filter coffee being poured into white and grey ceramic cup.

At MTPak Coffee, we offer roasters a choice of fully compostable coffee packaging options, including kraft paper, rice paper, and PLA-lined bags.

Our PLA and kraft paper packaging is able to break down into water, carbon dioxide, and organic matter, conforming to European EN 13432. The compostable seedling logo is clearly visible on all of our packaging that contains bio-based materials.

We can also include QR codes that can be printed directly onto coffee packaging. These can display as much or as little information as you choose, and can help ensure that instructions on the correct disposal of used packaging is clearly conveyed to customers.

Furthermore, we have a wealth of information on our Education Centre that can help guide roasters and coffee shop owners towards more sustainable practices and ethical choices when it comes to packaging.

For more information on compostable coffee bags, contact our team.

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