VOX terra, o.z., registered social enterprise
Slovakia
Circular supply chain, Recovery and recycling
SECTOR
Circular economy – agriculture, mushroom production
CHALLENGE
To analyse through a feasibility study, if substituting wood shaving/sawdust with used coffee grounds is viable in mushroom growing, technologically, environmentally and financially, and if it can be used as a sustainable business model in a social enterprise.
Main challenges were:
Securing a stable supply of coffee grounds
- Challenge: inconsistent volumes and willingness from cafés vs. much more reliable municipal sources.
- Mitigation: establish formal agreements (municipal contracts + 2–3 anchor cafés), set predictable collection windows (daily/early-morning pickup), and track kg/week per supplier as a KPI.
Preventing spoilage during collection & storage
- Challenge: CFG spoil rapidly (high moisture, high microbial load) and become unusable quickly.
- Mitigation: require collection → refrigerate or process within 12 hours (store ≤4 °C), or dry/solar-dry on-site; train suppliers in basic handling (drain, sealable bins, labeling, short-term refrigeration).
Pre-processing & handling protocols (training external partners)
- Challenge: suppliers need simple, repeatable steps so delivered CFG are usable and safe.
- Mitigation: create a short SOP and quick training (video + 1-page checklist) covering draining, minimal pre-drying, bagging, and basic hygiene; audit compliance and offer small incentives (e.g., returnable bins).
Substrate formulation & process changes when using CFG
- Challenge: replacing sawdust with CFG changes water retention, contamination risk and sterile-work needs.
- Mitigation: treat CFG as a supplement initially (start ≤10% dry weight for sensitive species; safe pilot at 25–50% for tolerant oysters), sterilize mixes (121 °C / 15 psi; ~90 min for sawdust/bran/CFG blends), increase spawn rate for sensitive species (lion’s mane → ~10% wet spawn), and run small replicated trials to lock optimum ratios.
Choosing the right species, customers & pricing
- Challenge: matching cultivable species (tolerant to CFG mixes) to market demand and acceptable price points.
- Mitigation: prioritize Pleurotus spp. for high CFG mixes; trial lion’s mane with conservative CFG% and higher spawn rates; do customer discovery with potential buyers (chefs, specialty grocers, health-food brands) to determine which mushrooms command premium prices and whether value-added formats (fresh, dried, powdered) improve margins.
SOLUTION
Creating a robust suppliers and customers connections and start using used coffee grounds in mushroom cultivation as a nutrient rich substrate by collecting it from local restaurants/coffees/municipal offices identifying market potential and customers need to address them by local production of desired mushrooms.
Providing product which can be marketed as environmental friendly, local and fresh, and which is visually appealing for customers to further process.
Creating further use for spent substrate.
So basically, solutions to set challenges were:
- Building a robust supplier & collection network
- Stabilising the input stream to prevent spoilage
- Pre-processing and substrate protocol adjustments
- Operator training, sterile workflow & quality control
- Product development, marketing & customer engagement
- Circular use of the spent substrate (post-crop valorisation)
- Monitoring impact and iteration
CIRCULAR ECONOMY STRATEGIES/BUSINESS MODEL IMPLEMENTED
Substituting raw sawdust or RUF hardwood brick as an input material and substituting it with coffee grounds which would otherwise be thrown out, or in best case scenario composted.
Benefits: Reduces upstream environmental pressures (deforestation, mining), cuts raw‐material costs, and improves material‐use efficiency.
Example: Blending 75 % spent coffee grounds (which would otherwise go to waste) with only 25 % virgin sawdust to grow mushrooms delivers the same yield with 67 % less primary substrate.
Value proposition (circular + local)
- Turn locally collected spent coffee grounds (SCG) into premium, locally grown mushrooms and downstream soil/compost products.
- Sell environmental benefit (waste diversion), freshness and provenance as core product differentiators.
Supply loop (closed-loop sourcing)
- Formal partnerships with municipalities, cafés and restaurants for regular SCG pickup.
- Standardised intake (weighing, QA), short holding time (≤12 h) and refrigerated or pre-dried buffer storage to preserve feedstock quality.
Production loop (upcycle → manufacture → reuse)
- Use SCG as a partial substrate input (blended with sawdust/supplements) to cultivate mushrooms.
- Post-harvest spent substrate is not waste: it is composted, used for vermiculture, converted to biochar/soil amendment, or used in community agriculture projects.
- This closes the material loop and reduces disposal costs.
Product & revenue model (diversified, value-added)
- Primary revenue: fresh mushrooms (oyster as volume, lion’s mane as premium).
- Secondary revenue: dried mushrooms, powdered extracts, value-added culinary packs for chefs, and bagged compost/vermicompost.
- B2B channels: restaurants, specialty grocers, institutional buyers. B2C: farmers markets, subscription boxes.
- Premium pricing justified by “upcycled + local + sustainable” story and traceable sourcing.
IMPACT
Environmental impact
1. Total Coffee Grounds Diverted (t/year) – currently 2.5, target 10.
2. Percentage of Substrate from Recycled Inputs (%) – currently 75 % coffee grounds, aiming for 80–90 % with additional waste streams.
3. Post-Harvest Substrate Reuse Rate (%) – target 100 % of spent substrate either composted or fed into secondary circular processes.
Economic impact
Revenue scenarios: annual revenue ranges from €12,500 (50 kg/week) → €21,250 (mid) → €30,000 (100 kg/week). Scaling from 50 → 100 kg/week increases revenue by +140% (from €12.5k → €30k).
Profitability threshold / breakeven sensitivity: project breakeven and attractive margins are highly scale-dependent — the report shows moving from pilot (50 kg/wk) to mid (75 kg/wk) converts a near-break-even social operation into a modest surplus (annual surplus rises from ~€1.1k → ~€8.2k). That’s a ~650% increase in surplus on those scenarios.
Value-added upside: processing mushrooms into dried powder increases weekly revenue per the example from €250 (fresh at 50 kg/wk) to €575 (dried powder) in the same volume — that’s a +130% revenue uplift for the processed SKU in that worked example. Gross margin improves even more (example shows fresh weekly gross ~€20.8 vs dried gross ~€392.4).
Input cost reduction: substituting coffee grounds for virgin sawdust can reduce primary substrate purchases substantially — example mix (75% CFG) reported ≈67% less virgin substrate required, lowering material cost exposure accordingly.
Social impact
Employment creation: the operation currently supports 0.5 FTE and is scalable to 2.0 FTE — a +300% increase (4× the current labour). This creates local jobs and social-enterprise opportunities. Current employee is psychiatric patient with lowered ability to be employed, so a disadvantaged person.
Supplier participation / community engagement: of 41 organizations approached (15 municipalities + 26 private companies), overall willingness to participate was 61% — 100% willingness among municipalities and 50% among private businesses, showing high public-sector buy-in as an anchor for the circular feedstock.
Quality of work & inclusion: social-enterprise framing and subsidized labour assumptions show low-barrier employment (half-FTE can operate pilot), and revenues are planned to be used to socialize profits (wage improvements or hiring), supporting local social objectives.
Food-security / diet substitution impact: if restaurants substitute 900 kg of meat with mushrooms, the report projects ≈21.3 t CO₂-e avoided — this is both an environmental and public-health/supply-diversification benefit at local/restaurant scale.
KEY TAKEAWAY
Secure supply first — anchor contracts with core suppliers to provide a reliable baseline; target daily/early-morning pickup and track kg/week per supplier.
Stop spoilage at the gate — require intake within 12 hours, or refrigerate/dry the substrate after use
Treat coffee grounds as a supplement, not a straight replacement — start conservative (≤10%–25% dry wt for sensitive species), pilot 50:50 only after validated runs; oysters tolerate much higher CFG%, lion’s mane needs caution.
Protect the process with sterility & speed — sterilize blends use higher spawn rates, and prefer smaller bag volumes to shorten spawn run.
Validate by experiment, not guesswork — run small, replicated trials and track colonization time, contamination rate before scaling.
Circular wins: reusing SCG reduces virgin substrate use (up to ~67% in some mixes), diverts tonnes of waste and delivers measurable GHG savings when mushrooms displace higher-impact proteins.
Diversify revenue to de-risk scaling — oysters for volume, lion’s mane as a premium; add dried/powder mushrooms and spent-substrate compost services to improve margins.