From Coffee Waste to Warm Homes!

From Coffee Waste to Warm Homes!

From Coffee Waste to Warm Homes: Sending 250+ Coffee Sacks to SisalWool Natural Fibre Insulation

At Stewarts Coffee Roasters, we’re always looking for simple, meaningful ways to reduce waste. One of our favourite ideas? Helping our used materials find a second life.

Recently, we sent over 250 used coffee sacks to Sisalwool, an innovative company creating natural‑fibre home insulation. Their products are breathable, safe, and eco‑friendly - perfect for anyone looking to make their home greener. Our sacks will be shredded into fibre to blend with wool or denim for insulation. The wool/cotton provides really good thermal performance, and the coffee sack material creates an excellent structure - making the insulation sturdier. One of our coffee sacks will help make up one slab of insulation!

The process starts with green (unroasted) coffee beans, which are shipped to Bremen, Germany, home to specialist decaffeination facilities. Once they arrive, the beans are thoroughly cleaned to remove things like dust and stones, then carefully sorted and prepared for the specific decaffeination process they’ll go through.The beans are then poured into a large 4‑tonne tank where ethyl acetate is added. They soak for around eight hours at roughly 70°C, allowing the EA to bind to and remove the caffeine. During this time, the solution is changed anywhere between six and ten times depending on how much caffeine the beans contain to begin with.Once the caffeine has been removed, the beans go through a steam‑stripping stage to ensure no ethyl acetate remains. Steam is pumped into the tank, with the first 90 minutes at 100°C and a final 60 minutes at 105°C. Since ethyl acetate has a boiling point of around 70°C, this step ensures everything is fully removed.

After that, the coffee beans are dried, polished and packed, ready to make their way back to us for roasting. The caffeine that’s extracted during the process doesn’t go to waste either – it’s refined and used elsewhere.

After that, the coffee beans are dried, polished and packed, ready to make their way back to us for roasting. The caffeine that’s extracted during the process doesn’t go to waste either – it’s refined and used elsewhere.

Caffeine-Free decaffeination process explained - Mexican Mountain Water

Mountain Water is a chemical‑free decaffeination method that uses fresh water sourced from Pico de Orizaba, Mexico’s highest mountain. The process gently removes caffeine from green coffee beans while keeping the coffee’s natural flavour intact.

Decaffeination takes place at the Descamex facility in Mexico, where the beans are washed using pure mountain spring water. The green coffee is immersed and rinsed in large tanks, allowing the caffeine to be gradually extracted without the use of solvents.
Once the caffeine has been removed, the beans are slowly dried over several hours before being prepared for export and roasting. The result is a decaf coffee that remains rich, full‑bodied and balanced, while being 99.9% caffeine‑free.Because this process relies solely on water, the soluble flavour compounds of the coffee are preserved, helping maintain the original character of the bean in the cup.

Our Barista Booster will aid you build your foundations and reach a level of quality on par with the world of specialty coffee shops!