The Ultimate Guide to Sustainable Coffee Bags: Part 2

Understanding certifications and the practical limitations and design considerations of sustainable materials.

This is a complicated space - with no right or wrong answer, and if you've made it this far, you're obviously highly-engaged. In Part 2 of our Guide to Sustainable Coffee Bags we take a slightly deeper dive into the considerations of various sustainable coffee bag materials, formats and certifications. Our aim is to provide you with valuable insights and tools to navigate this complex and challenging space.

Understanding compostable certifications for coffee packaging.

What is the difference between home composting and industrial (commercial) composting?

Home composting and commercial composting differ in their scale, management, and end use. Home composting is typically done on a small scale, such as in a backyard or on a balcony, and involves processing organic waste from the household, such as food scraps and yard waste. It can be done using a variety of methods, such as compost bins, compost tumblers, or vermiculture, and can produce a nutrient-rich soil amendment that can be used to improve soil health in home gardens and landscaping.

Commercial composting, on the other hand, is done on a larger scale and typically involves the collection and composting of organic waste from multiple sources, such as restaurants, grocery stores, and other businesses. Commercial composting facilities use specialized equipment and techniques to compost the organic waste quickly and efficiently, and may produce a variety of end products, such as soil amendments, mulches, and fertilizers, that are sold to consumers, farmers, and landscapers.

Probably the most important differentiating factor is that commercial composting facilities generally run at a much higher temperature than home composts, generally 50-60C (122-140 degrees Fahrenheit) as opposed to 20-30C (68-86 degrees Fahrenheit), and it is that additional temperature that helps process the organic matter with greater speed.

What are the major composting certifications?

Different regions have different compostability certifications. The three main certification bodies by region are below:

Different types of compostable materials suitable for compostable coffee pouches.

When looking at which type of compostable material to choose from, it is critical to get this right. There are few different options for materials, ranging from transparent films to metalized films or to white / kraft paper.

Certified compostable materials vs Certified Compostable coffee pouches.

It's important to understand the distinction between certified compostable materials and certified compostable pouches (or bags). Coffee pouches often consist of multiple layers of materials, laminated together to create a structure with greater functionality than if you just used a single layer of material. Additionally coffee pouches often require degassing valves and valves and zippers.

As such there are often between 4 and 6 (sometimes more) different components that go into the manufacturing of a compostable coffee pouch. In order to have a compostable coffee bag that has a compostable certification, like BPI, each of the individual components needs to be certified compostable, and the final assembled pouch much also pass compostable certification. This certification process for a full pouch is more challenging than for individual components.

It is fair to say that in general, compostable materials are hard to manufacture with, but relatively it is easier to produce a coffee pouch that 'is made from compostable materials' than it is to produce a full pouch that carries compostable certification (including valves, zippers etc). The complexity in the space can make it hard for businesses to navigate, and unfortunately this hasn't been helped by some large producers making bogus claims on compostability. One large incumbent in the US has been marketing a 60% compostable pouch, as a compostable packaging product for years which is as blatant a greenwashing activity as you will find.

Limitations of compostable packaging.

Compostable flexible packaging materials have certain limitations which it is important to be aware of. They perform very differently to plastics and have a limited shelf life.

Weight limitations.

In general we do not recommend the use of compostable materials for anything over 1kg or 2.2lbs, as there is a high risk of failure unless the bags are handled with extreme care.

To be on the safe side we usually recommend intensive trialing for anything over 500 grams of 1.1lbs. Every business has different considerations and supply chains but better to err on the side of caution and test properly before rushing into anything.

Seal strength and compostable pouches for eCommerce or D2C models.

Compostable materials have weaker seal strength compared to traditional plastics. When used for e-Commerce or direct-to-consumer channels where rough handling is likely, the risk of failure increases, even at lower weights.

Again we would strongly recommend rigorous testing for all products sold in such channels.

Be aware of shelf-life of the material - don't over order.

Compostable materials by their very nature are designed to have a shelf life and require specific conditions to initiate the composting process (heat, moisture and microbial activity). However, over time, the quality of the pouches will gradually decrease over time, especially in hot and humid environments (aka Summer in most parts of the world). This will manifest itself with greater failure rates, breakages, and delamination.

Grounded guarantees the quality of our compostable pouches for 12 months from the delivery date.

Use with vertical form-fill-seal machinery.

Despite numerous trials we have struggled to get compostable materials to work for typical retail weights and formats of coffee. Compostable materials are generally fine for smaller snack foods.

When looking for a sustainable material for larger format roll-stock we recommend Post-consumer recycled materials as the best solution (as at the point of writing this article mid 2023). However, material science is rapidly evolving, and we are constantly testing new materials.

Give the product extra space in the bag.

Due to the potential issues with seal strength, it's beneficial to create a little extra space within the bag when using compostable materials. This can help reduce stress on the seals and minimize the risk of failure.

This is not to say do not use compostable coffee pouches but most people using compostable materials are transitioning from traditional plastics which are almost bulletproof and almost entirely valueless, and compostable materials are very different, they have been designed to be much more fragile.

As such it is important to go into the process with your eyes wide open in order to get the best result and avoid costly breakages. Grounded produces and sells millions of compostable pouches annually and the only issues we encounter are when expectations have not been managed properly.

Specific considerations for block bottom coffee pouches.

Block bottom pouches are increasingly the coffee pouch of choice for specialty coffee roasters around the world. They are sturdy, they look good on the shelf and they have lots of real estate for branding and messaging. However there are a few important things to understand about manufacturing this format.

Higher cost compared to traditional formats.

Block bottom pouches are generally more expensive than traditional formats like stand-up pouches. The reason for this is that they require more material and involve a slightly complex manufacturing process. The combination of these factors contribute to higher costs.

Printing considerations.

When it comes to printing on block bottom pouches using print plates, an important point to note is that it requires two sets of print plates. One set is used for the front, back, and base of the pouch, while another set is needed for the two side panels. This can significantly increase the set up cost, and depending on the complexity of the artwork, it may even double the plate cost.

Special zipper requirement.

Block bottom pouches typically require a special kind of zipper called a “ripper zipper” or “pocket zip”. This type of zipper attaches only to one side of the pouch. Using a standard zipper, on the other hand, necessitates creating what is known as a “terminated gusset”. In practical terms, this constricts the opening of the pouch, making it harder to fill and reducing the overall capacity.

Home compostable block bottom pouches.

Grounded does not recommend using home compostable block bottom pouches for coffee without rigorous testing to ensure that they work effectively within your specific supply chain. It’s crucial to thoroughly evaluate their performance and compatibility before incorporating them into your packaging strategy.

Printing considerations.

One of the most important parts of the process is understanding print considerations and how this varies by material and process. There are two main types of flexible packaging print techniques:

1. Plate based printing - flexographic or rotogravure.
2. Digital printing.

Here's a brief overview of each approach, along with their pros and cons:

Getting a bit further into the weeds…

Print substrate - printing on paper vs printing on film.

Printing on different substrates yields very different results. Printing on film generally produces sharp and accurate results, while printing on paper is more challenging. Paper is porous, causing the ink to soak into it.. This makes it much difficultto achieve large, consistent blocks of colour and fine details in printing.

If your desired artwork is unlikely to print well on paper, there are two alternative approaches:

1. Reverse printing an outer layer that gets laminated to the paper, allowing the paper colour and texture to remain visible.
2. Printing a “paper finish” onto a film with a matte or rough matte coating. Although this sounds a bit yuck, it is surprisingly good.

Grounded has built a software tool called Blueprint where you can test the differing print results you get on different substrates in real time to avoid time and cost in sampling.

What is the difference between Pantones vs CMYK.

Pantone printing utilizes a specific set of standardized ink colors, allowing for precise color matching and consistency across different printing processes. Onn the other hand, CMYK is a subtractive color model that combines cyan, magenta, yellow, and black inks to create a wide range of colors. However, it may result in slight variations and limitations in color accuracy.

While Pantones are generally more accurate and preferable for colour precision, it's important to note that they can appear different on different substrates. As such, if you like the way your brand colours appear on a particular print substrate (even if you have specified pantones in your artwork) it is often helpful to also provide a physical example to match the desired colour, as there will be subtle variations in the printing process to achieve the intended colour.

Can you make a paper coffee pouch that is recyclable?

Most paper coffee bags have layers of plastic and aluminum as part of their overall structure. This means that the vast majority of coffee pouches that have a paper finish are unable to be recycled as part of either the plastic or paper recycling streams.

Emerging technologies may soon allow for high-barrier paper pouches that can be recycled in the paper stream. However, currently, these technologies are challenging, and existing solutions compromise product quality. Grounded aims to introduce a high-barrier, paper-recyclable coffee pouch to market in late 2023.

If you want to have a paper-like finish on your coffee pouch the best route to take is to go for a compostable material as that is the only way that, realistically, they have any chance of ending up anywhere that isn't landfill.

Finishing note.

It is super important to understand the print, material and format limitations before getting too far through the packaging development process for your eco-friendly coffee pouch project.

Sustainable materials present a range of issues that traditional materials do not.

At Grounded we are singularly focused on replacing plastics with sustainable materials that create better outcomes for the planet.