Barrier values in bioplastics

Sustainability and enjoyment don't have to be enemies. Our HOMEcap coffee capsule is the proof! It's a game-changer in the world of eco-friendly packaging, and it'll keep your coffee's flavour safe. We've used an organic PBS mix and our skills in bioplastics to make the HOMEcap, so it's not only good for the planet, it's also one of the best organic capsules out there.

The importance of WVTR and OTR for coffee capsules

In order to understand why aluminium and conventional plastic have been predominant up to now, it is worth taking a closer look at the technical requirements for coffee capsules. Here, the two measured values WVTR (Water Vapor Transmission Rate) and OTR (Oxygen Transmission Rate) a crucial role:

  1. Water Vapor Transmission Rate:The flavour of coffee can be affected by moisture, so it's important to keep the capsule sealed to maintain the coffee's freshness. The rate at which water vapour passes through the material is a good indicator of its ability to block moisture. Materials with a low WVTR value are better at keeping coffee fresh because they allow only a small amount of water vapour to pass through.
  2. Oxygen Transmission Rate:Oxygen can oxidise the coffee and affect the flavour. The OTR value of a material indicates how much oxygen passes through the material into the capsule. A low OTR means that there is less oxygen in and out of the capsule and the coffee is better protected from flavour degradation.

Traditional aluminium and plastic capsules provide an excellent barrier to water vapour and oxygen, ensuring a long shelf life and preserving the flavour of the coffee. For a long time, bioplastics were unable to meet these protection requirements, but a lot has happened in recent years.

Optimum protection of freshness and flavour

For our HOMEcap coffee capsules, we rely on Bio-PBS (bio-polybutylene succinate), a high-performance biopolymer that offers both good barrier properties and biodegradability. Even our first version of the capsule, which was reinforced with sunflower seed husks, achieved impressive results in terms of flavour protection: with a water vapor transmission rate of 0,03 g/(capsule x day) and a oxygen transmission rate of 0,007 cm³/(capsule x day) it was already at a competitive level.

With our new HOMEcap barrier we have improved these values even further. This means that the coffee flavour is optimally protected without the use of aluminium or conventional plastics. This advanced barrier performance shows that bioplastic capsules can compete with traditional materials - without harming the environment.

Certified home compostability - the more sustainable choice

A particular advantage of our HOMEcap capsule is that it is fully certified in accordance with the OK Compost HOME by TÜV Austria. This means that our capsule can be decomposed not only under industrial composting conditions, but also in domestic compost - together with the coffee content and the sealing film. This certification sets HOMEcap apart from many other products on the market that either only certify the capsule as compostable without the coffee or the foil, or require industrial composting at higher temperatures (50-60°C).

The home compostability is a particularly important aspect of sustainability. Unlike industrial composting, which takes place in controlled facilities under artificially high temperatures and oxygen, home composting takes place under natural conditions.

Recycling is often just a theory: the truth about aluminium and plastic capsules

Aluminium and plastic capsules are often promoted as recyclable packaging options. But the reality is different:

  • Aluminium capsules:The production of aluminium is extremely energy-intensive, involves disastrous working conditions and pollutes the environment with waste and CO2 emissions. Although aluminium is theoretically recyclable, thin-walled coffee capsules require the use of pure virgin material to achieve the necessary stability. Therefore, recycled aluminium cannot be used to make new coffee capsules; instead, it is reused as 'scrap' and processed into products with lower quality requirements. This means that the recycling cycle is far from being a true circular economy.
  • Plastic capsules:Many plastic capsules are made of composite materials, which are made up of different layers of plastic to provide the necessary flavour protection. However, these composite materials are almost impossible to recycle and many capsules end up in residual waste where they are incinerated or landfilled. The environmentally friendly alternative to composite materials is our HOMEcap capsule, which is home compostable.

The future of coffee enjoyment: sustainable, compostable and flavour-tight

With the HOMEcap barrier, we have developed a coffee capsule that makes both technical and environmental sense. It combines all the requirements for coffee enjoyment - from optimum aroma protection and easy disposal in the home compost to full certification by the European Eco-label. TÜV Austria. Our capsules offer an environmentally friendly alternative to aluminium and plastic capsules and are the first choice for coffee lovers who value a sustainable lifestyle.

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