It began in a modest café, as many revolutions do: the gentle drip of espresso, the hushed hum of conversation, and a pile of spent coffee grounds that nobody quite knew what to do with. But from that waste has blossomed a daring idea — that the very refuse of our daily brew could help build a greener future, one printed layer at a time.
From Café Waste To Creative Material
Michael Rivera, a computer scientist and designer at the University of Colorado Boulder, recounts the moment: during the COVID-19 lockdown, a local café he frequented began accumulating mounds of used coffee grounds—grounds normally destined for compost or landfill. As he looked at them, a spark settled in his mind: what if those “waste” grounds could be reused as material in 3D printing?
This curiosity led Rivera and his collaborators to develop a surprisingly simple yet elegant technique: they dry the spent grounds, mix them with small amounts of cellulose gum and xanthan gum (both edible, compostable additives), then add water to form a paste.
That paste—rather like thick peanut butter in texture—can be extruded by a modified 3D printer to make objects.
Within this coffee-borne medium, Rivera’s team has printed planters, jewelry, even espresso cups. Once the objects are no longer needed, they can be ground again and reused—completing a little loop of reuse. “If you don’t want the printed object anymore, you can toss it into a grinder and use the grounds to print again,” Rivera says.
Though Rivera acknowledges this technique may never dominate the 3D printing marketplace, he views it as a stepping stone—proof that sustainable alternatives exist, and that they can be accessible to designers, hobbyists, and communities alike.
The Magic Of Mycelium: Coffee Meets Fungus
A parallel thread of innovation blooms from the University of Washington, where doctoral student Danli Luo and her team have taken Rivera’s idea and woven into it another living element: mycelium—the root-like network of mushrooms.
Their process, published in 3D Printing and Additive Manufacturing, involves mixing spent coffee grounds with brown rice flour, xanthan gum, water, and spores of Ganoderma lucidum (Reishi mushroom).
They coined a paste called “Mycofluid,” which is extruded through a custom 3D printer head. After printing, the object is incubated for about ten days in controlled humidity. During that time, the mycelium grows outward, forming a “skin” over the printed shape—and even binding separate printed pieces into a cohesive whole.
The result: fully compostable structures, with mechanical strength comparable to polystyrene foam (Styrofoam), yet derived entirely from organic waste. In moisture tests, the material absorbed just 7 % more weight when submerged for an hour and reverted to its prior form upon drying.
“You could imagine replacing Styrofoam packaging with something that grows, fuses, and then vanishes harmlessly,” says Luo.
But there are challenges. The team notes that Mycofluid’s ideal feedstock is relatively homogeneous coffee grounds—variations in particle size, moisture content, and contaminants can impair performance. Scaling the process beyond artisanal or research applications will require controlling for those inconsistencies.
Still, the promise is compelling: a future where packaging, interior parts, small consumer goods—even art—can grow from what was once trash.
Beyond The Lab: Creative Experiments In Design
The notion of printing with coffee waste has already found curious expressions beyond academic labs.
In Barcelona, a coffee shop named D·Origen collaborated with architect Arturo Tedeschi and a sustainable 3D firm, LOWPOLY, to create furnishings and installations from 3D-printed materials composed largely of recycled PLA and spent coffee grounds.
Stools, lamp shades, even the bar counter were constructed from a material called LOWIMPACT, which the makers say is “98% organic.”
Elsewhere, sustainability-minded designers have explored using waste coffee as filler or composite content in large-scale 3D printing. Though pure coffee-ground printing is still niche, the principle—infusing biodegradable or waste-derived materials into additive manufacturing—is gaining traction across the field.
For instance, 3DPrintingIndustry recently reported on the UW team’s work, emphasizing that by removing reliance on molds (used in conventional manufacturing), the “bio-welding” of printed parts by mycelium growth unlocks more flexible design possibilities.
Still, critics caution that incorporating biomass fillers like coffee grounds can increase energy demands or complicate recycling. Some experts note that while adding natural fibers to plastics may reduce some harms, it also “makes recycling more labor and energy intensive.”
Impacts, Limitations, And Future Pathways
This is the crux: the interplay between innovation and scalability, between optimism and realism. While the coffee-based printing methods are technically elegant, their real-world adoption hinges on several critical factors:
- Material Consistency – Unlike virgin polymers, coffee grounds vary by roast, moisture, contamination, and processing. Ensuring uniform particle size and purity across large batches is nontrivial.
- Mechanical Limits And Durability – Strength is promising, but these materials may not yet match the reliability of high-performance plastics under all conditions.
- Processing Infrastructure – For mass use, modifications to printers, supply chains, sterilization methods, and post-print curing would be needed.
- Composting And End-Of-Life – Though all components are compostable, real-world composting systems are uneven globally.
- Energy And Life-Cycle Trade-Offs – The energy cost of drying, sterilizing, transporting, grinding, and printing may offset some of the environmental gains unless powered by renewable energy.
- Adoption Barriers – Designers and manufacturers may resist switching from familiar plastics. Market standards and cost will determine uptake.
Yet, it is precisely here—at the junction of promise and challenge—that innovation often blooms. These experiments invite us to reconsider linear production, encouraging circular thinking: coffee cups to printer cups, packaging to soil, design to biodegradation.
Looking Ahead: A Hopeful Horizon
Imagine a future where the humble café is more than a place for coffee—it’s a hub of circular manufacture. Grounds collected in bulk, cleaned, processed, and redistributed as filament or bio-inks.
Where artisanal designers, local makers, and students can print compostable objects at home, with materials harvested from their own waste streams. Where packaging disintegrates harmlessly, leaving nutrients behind.
That future is not guaranteed—there is no magic wand to scale such systems overnight. But coffee-based 3D printing shows it is possible to reimagine waste as a resource, to invert the dynamic where we take, make, and discard. In doing so, it reveals another path forward: one where smaller steps—one café, one printer, one mycelial skin—converge into systemic change.
As Rivera puts it, “you can just buy a few things at the supermarket and get started.” It’s a modest invitation, but it carries a bigger message: that sustainability need not wait for perfect policies or massive funding. It can begin with curiosity, adaptation, and the courage to brew something new from what we already have.
Sources:
AZO Materials
Vegconomist
Colorado
