Illustrated mockup. Product photos coming soon.
A little cotton pouch with a big job. Inside is a pod made from used coffee grounds, activated charcoal and bicarbonate of soda. It's designed to absorb unwanted smells, rather than cover them up with a new one.
Inside every pouch is a small cuboid pod. We make it by mixing dried, used coffee grounds with PCL and moulding the mix into shape. Then we press activated charcoal and bicarbonate of soda into the outside of the pod, where they have the most contact with the air.
Every pod is speckled and slightly different, because no two batches of coffee are exactly the same. The muslin-style cotton pouch lets smell molecules straight through, because the gaps in the weave are thousands of times wider than the molecules. It also catches any loose powder and carries our logo on the front.
Each part of the pod tackles smells in a different way, so together they cover more kinds of smell than any one of them alone.
Charcoal full of tiny pores, with 1,000–1,500 m² of surface in every gram. Smell molecules drift in and stick to the walls. Works on a wide range of smells.
Many bad smells are acids, like the isovaleric acid behind foot odour. Bicarb reacts with them to form salts that don't evaporate, so you can't smell them.
The grounds bind with PCL to form the pod and trap some smell gases themselves. They are weaker than charcoal on their own, which is why we added it.
Hinoue, M. & Hori, H. (2019). Journal of UOEH, 41(4), 417–424.
Researchers passed gas carrying 14 different volatile organic compounds (VOCs), a family of chemicals behind many everyday smells, through ordinary used coffee grounds. They measured how much of each the grounds captured, and found that moisture in the grounds made a difference for some compounds.
Read the study →Kante, K., Nieto-Delgado, C., Rangel-Mendez, J. R. & Bandosz, T. J. (2012). Journal of Hazardous Materials, 201–202, 141–147.
A team at the City College of New York turned used coffee grounds into a carbon material that captured hydrogen sulphide, the gas behind the rotten-egg smell of sewers. They linked its performance to nitrogen found naturally in coffee, including in caffeine.
Read the study →Kawasaki, N., Kinoshita, H., Oue, T., Nakamura, T. & Tanada, S. (2006). Journal of Oleo Science, 55(1), 31–35.
Researchers in Japan treated coffee grounds with microwaves and tested them on ammonia, a sharp, pungent smell. Some of the coffee-ground materials held more ammonia than activated carbon, the material used in many air filters.
Read the study →The honest bit: the first study tested used coffee grounds as they are; the other two processed the grounds into carbon first. Raw grounds like ours are much weaker than carbonised ones, so we don't claim our grounds work like activated carbon. That job goes to the charcoal and bicarb. How well a pouch works in real life depends on the space, the smell and how long it has been in use.
We sealed each mix in a container with garlic for 7 hours. Ten testers smelt the garlic on its own, then each container in a random order. We then took the garlic out, left the pods in for another 5 hours and tested again.
| Mix | Garlic still in | Garlic removed |
|---|---|---|
| 70% PCL, 30% coffee | 0% | 0% |
| 60% PCL, 40% coffee | 0% | 10% |
| 50% PCL, 50% coffee | 0% | 30% |
| 40% PCL, 60% coffee | 10% | 70% |
| Final formula: 40% PCL, 55% coffee, 5% charcoal & bicarb | 20% | 100% |
The pod works best once the smell source has gone, clearing what lingers in a shoe, bag or drawer. This was a small test run by our team, not a lab study, but it's real evidence from our own product.
Our rule from day one: every part of the product and its packaging should be compostable.
When your pod has done its job, it's designed to be composted rather than thrown in the bin, and the cotton pouch can be reused or composted too.
Rescued after brewing and given a second life. Naturally biodegradable.
Polycaprolactone, a biodegradable material that binds the grounds into a solid pod. We chose it over resin.
A natural carbon that traps smell molecules in its pores.
The same baking soda you'd find in a kitchen cupboard.
A natural cotton drawstring bag from a UK supplier, printed with our logo.
We didn't start with a pouch. We started with a bin full of used coffee and a lot of ideas.
Our team met for the first time and set two rules: whatever we make has to turn a profit, and it has to be good for the planet.
We picked our name, a nod to the coffee grounds at the heart of everything we make.
We explored trainer-cleaning soap, coasters, jar openers, keyrings, fidget stones and tealight holders before narrowing it down.
We decided early on that the pouch shouldn't smell of coffee. Its job is to absorb odours, not cover them with a new one.
We chose PCL instead of resin to hold the grounds together, and searched UK-only suppliers for a cotton pouch we could print with our logo.
The team voted to make the Scent Pouch our main product, with a Christmas decoration alongside it.
Coffee grounds alone weren't strong enough, so we added activated charcoal and bicarbonate of soda. Our final formula passed with all 10 blind testers.
You'll find us at local trade fairs and markets in the run-up to Christmas.
Come and see us at a local trade fair.