If you’ve ever looked closely at a coffee packaging spec sheet, you may have come across a number called OTR, or Oxygen Transmission Rate. It sounds technical and a bit nerdy, but the idea behind it is pretty simple.
OTR tells you how much oxygen can pass through a packaging material over a given period of time. And when you’re packaging roasted coffee, that matters, because oxygen is one of the key things that affects how long your coffee keeps tasting like… well, coffee.
What does OTR actually measure?
Oxygen Transmission Rate measures how much oxygen passes through a packaging material in a day. It’s usually expressed as: cc/m²/day.
In simple terms, the lower the OTR number, the stronger the packaging’s oxygen barrier. A lower OTR means less oxygen is able to pass through the packaging and reach the coffee inside.
Why does oxygen matter for coffee?
Roasted coffee contains oils and aromatic compounds that give it much of its flavour and aroma. Once those compounds are exposed to oxygen, oxidation begins. Over time, that process can change the flavour, aroma and overall quality of the coffee. Oxidation starts after roasting and never really stops.
Good packaging can’t stop that process completely, but it can help slow it down.
That’s why understanding the barrier performance of your packaging is important, particularly if your coffee needs to maintain quality over longer periods of storage or distribution.
What do OTR numbers look like?
Different packaging structures can have dramatically different oxygen barrier properties. High-barrier laminates can have an OTR below 1 cc/m²/day, providing a very strong barrier against oxygen.
At the other end of the spectrum, something like uncoated kraft paper without a barrier layer can allow substantially more oxygen through. That represents a very different level of protection for the coffee inside.
But there’s an important distinction here: The lowest possible OTR isn’t automatically the right packaging choice for every coffee.
The barrier trade-off
Traditionally, foil laminate structures have been used extensively in coffee packaging because they offer excellent barrier performance. The challenge is what happens after the bag has been used.
Foil laminates are generally made from several different materials bonded together. Because those layers are difficult to separate, they can be challenging to recycle through current Australian recycling systems.
So when choosing packaging, barrier performance is only one part of the equation. Increasingly, roasters are also considering what the packaging is made from, how it can be disposed of and what role it plays in their wider sustainability goals.
Today’s packaging options give coffee roasters more choice
Coffee packaging has evolved significantly over the last decade especially.There are now higher-barrier alternatives designed with circularity in mind, including options such as:
- Mono-material PCR bags, made using post-consumer recycled plastic and a single ‘mono’ form of plastic which increases the chances of it being conditionally recycled
- Higher-barrier compostable structures
The right option depends on your coffee, your supply chain and how the product is ultimately used, and discarded by customers at the end of its life.
And again, the strongest possible oxygen barrier isn’t necessarily required in every situation. If coffee is roasted, packed and moving relatively quickly into your customer’s hands, a packaging structure with a different barrier profile might still be appropriate.
What OTR does your coffee actually need?
There isn’t one OTR number that every coffee roaster should be aiming for; it depends on things such as:
- How quickly the coffee is sold after roasting
- How long it might spend in storage or distribution
- The expected shelf life of the product
- How customers are likely to store the coffee once they receive it
For some coffees, storage instructions can form part of the solution too. For example, encouraging your customers to transfer coffee into an airtight container after opening can help limit ongoing exposure to oxygen.
The goal is to find a packaging structure that provides the protection your coffee actually needs without automatically defaulting to the highest-barrier material available.
One question worth asking your packaging supplier
When you’re comparing coffee bags, don’t just ask what the packaging is made from. Ask:
“What is the Oxygen Transmission Rate of the packaging options you’re recommending?”
Understanding the actual barrier performance makes it much easier to compare packaging structures and make an informed decision about what’s right for your coffee. At EcoBarista, we believe you should be able to see the real numbers behind the packaging you’re considering.
So if you’re speaking with us about coffee bags, we can provide the OTR data for the different structures we offer and help you weigh up barrier performance and sustainability, taking into account the way your business runs and how your coffee moves from roastery to customer.
