Coffee Bag Sauna

About six months ago our friend Harrison Gardner asked us to start keeping him all of our coffee bags once we had emptied them. He didn’t know exactly what he was going to do with them but he knew that they were good for something other than keeping our coffee beans fresh. He worked as a coffee roaster and barista before spending a number of years with Earthship Biotecture.

The technology that goes into making metallised film packaging is somewhat hi-tech. The same  material that is produced for our coffee bags is also used by NASA for Spacesuits. It cannot be recycled due to the multiple sealed layering in the packaging. So something that is built to last will literally last forever.

Many people have looked at this repurposing problem before. Some cafes refill their bags with the used grounds, which are given to customers for composting or growing mushrooms. This is great, it is giving the bag one more life. But that life is relatively short and what does the customer do with it then? Throw it in the bin most likely so it is still ending up in landfill.

The technology in this packaging has way more value than this and we should have options as to how to reuse it. We know that it is:

air tight

water tight

heat reflective


….this is all the kind of stuff that builders are looking for all the time, right?

So as an experiment Harrison decided to use it to line a sauna that he was building out of an old stone ruin. And we all got to help out. The structure was to be: stone outer walls – fibre insulation (taken from the roof of another dilapidated building) – stud wall – vapour barrier + heat reflector (coffee bags) – wooden cladding.

For this vapour barrier/heat reflector the first thing to do was to cut open all the old coffee bags. Then reseal them together with an iron to make long sheets of material. These sheets were then fixed to the stud work on top of the insulation before the cedar cladding was attached.


















This was a time consuming job and very much a DIY experiment. But it worked.

What if every cafe was to save their coffee bags for someone to collect, surely there could be a machine that could take all this material and do what took us the guts of 2 weeks in the guts of 2 hours. And then sell it by the roll.

That machine probably already exists…….



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