Rotterzwam

What Rotterzwam does

Rotterzwam B.V. is a Rotterdam-based circular urban mushroom farm founded in 2013 by Siemen Cox and Mark Slegers. The company cultivates oyster mushrooms and specialty varieties (Lion's Mane, Shiitake, Nameko, King Oyster) on urban residual streams - primarily spent coffee grounds collected from businesses and HORECA, supplemented by beer spent grain and wood chips. Operations run from a facility at Schiehaven 26 housing 8 climate-controlled growing containers with capacity for 12,000 kg of substrate, producing roughly 13,000 kg of mushrooms annually and rescuing 40+ tonnes of coffee grounds per year from incineration (419,840 kg cumulative since inception, with 144,164 kg CO2-equivalent emissions avoided).

The core technology is a modular substrate-based cultivation system that converts urban waste into fruiting substrate. Sterilization know-how developed under the 2023 Kansen voor West provincial grant - demonstrating successful cultivation of 5 mushroom varieties on sterilized coffee grounds - is now being industrialized through the SPORO substrate factory under license from Rotterzwam. The company has also developed a home-growkit system (recycled-plastic bucket, spawn, video instructions) enabling distributed cultivation by consumers on their own household coffee waste. Since 2013 the growkit program has onboarded 100,000+ "aanrecht-agrariërs."

The business operates five distinct revenue streams: (1) B2B coffee-ground collection subscription at €55-€265/month across 25+ enterprise accounts including Nationale Nederlanden, TU Delft, Marriott Rotterdam, Arcadis, MVRDV, and Gemeente Rotterdam; (2) HORECA fresh mushroom and plant-based snack wholesale (bitterballen, kroketten, saucijzenbroodjes, dumplings, Shoyu sauce) via Sligro, Bidfood, and Karel van der Vorm; (3) direct e-commerce of growkits, spawn, accessories, and gift packages via a Shopify webshop (with international shipping to BE/DE/FR/IE/IT/ES/UK/SE); (4) on-site workshops, facility tours, the Mushroom Master Program, and e-learning courses for aspiring farmers; and (5) paid speaking engagements on circular economy. Co-founder Siemen Cox departed in 2022; Mark Slegers remains as Directeur with a small (1-10) team. The company is B-Corp certified (Top 5 Best for the World 2022, Environment) and has won 8 industry awards.

Name

Rotterzwam

Legal name

rotterzwam B.V.

Website

https://rotterzwam.nl

Company type

Private

Founded year

2013

Operating status

Operating

Headcount range

1–10 employees

Short description

Rotterzwam is a Rotterdam-based circular urban mushroom farm founded in 2013 that cultivates oyster and specialty mushrooms on collected coffee grounds, selling fresh mushrooms, plant-based snacks, home growkits, B2B waste-collection subscriptions, and circular-economy education to HORECA, corporates, and consumers.

Ownership category

akta.pro rank

Product category

Urban Mushroom Farming

NAICS

Mushroom Production (111411), Food Crops Grown Under Cover (11141), Other Vegetable (except Potato) and Melon Farming (111219)

SIC

Agricultural Production-Crops (100), Canned, Frozen & Preservd Fruit, Veg & Food Specialties (2030), Food And Kindred Products (2000)

akta.pro primary industry

Mushroom & Fungi Production (Indoor/Protected) (AFAGAHAK)

akta.pro secondary industries

Wild & Cultivated Mushroom Foraging and Production (AFAMAFAD), Frozen Plant-Based & Vegetarian Meals (CRADADAF), Circular Economy & Resource Efficiency (BPADALAM)

Keywords

• Urban mushroom farming
• Circular food production
• Coffee waste valorization
• Plant-based snacks
• Sustainable agriculture

Headquarters

HQ city

Rotterdam

HQ country

Netherlands

HQ region

Europe

Offices3 records

Markets served

GTM type

B2B and B2C

Offering type

Hardware or Manufacturing

Cost components

Operations, Supply Chain, Personnel, Marketing or Sales, Infrastructure, Technology or R&D

Revenue model

1. Fresh Mushroom Sales: Sale of fresh oyster mushrooms and specialty mushrooms (Lion's Mane, Shiitake) to consumers, restaurants, and businesses. Sold directly from kwekerij or through wholesale channels.
2. Mushroom Snack Products: Production and sale of processed plant-based snacks including bitterballen, kroketten, sausages, and dumplings made from oyster mushrooms. Sold through wholesale, direct, and HORECA channels.
3. Growkit Sales: Sale of home mushroom cultivation kits containing spawn, bucket and instructions for consumers to grow oyster mushrooms on their own coffee grounds at home. Repeat purchases of spawn for continued cultivation.
4. Coffee Grounds Collection Service (B2B): Monthly subscription service collecting coffee grounds from businesses and HORECA in the Rijnmond region. Packages from €55/month (HORECA) to €265/month (businesses with 100kg+). Linked to product offtake commitments.
5. Education & Workshops: Revenue from facility tours, mushroom cultivation workshops, Mushroom Master programs, and e-learning courses. Private workshops available from €65-95 per person.
6. Speaking Engagements: Booking fee for co-founders Mark Slegers or Siemen Cox as inspirational speakers on sustainability and circularity topics.

Pricing tiers

Go-to-market motion4 records

Distribution channels7 records

Marketing channels8 records

Core offering

Rotterzwam cultivates oyster and specialty mushrooms (Lion's Mane, Shiitake) on urban residual streams—primarily coffee grounds collected from businesses and HORECA—and processes them into fresh mushrooms, plant-based snacks (bitterballen, kroketten, dumplings, ravioli, shoyu sauce), and home cultivation growkits. The company also operates a B2B coffee grounds collection subscription service, runs workshops and tours at its Rotterdam kwekerij, and offers motivational speaking engagements on circular economy topics.

Product overview

Rotterzwam operates as a circular economy business cultivating mushrooms on urban waste streams in Rotterdam. The core product portfolio centers on the Paddenstoelen Growkit Oesterzwammen (home cultivation kit) and fresh mushrooms (Oesterzwammen, Lion's Mane), which are processed into premium plant-based Dutch snacks including bitterballen, kroketten, and saucijzenbroodjes. The product line has expanded to include fermented products (Paddenstoelen Shoyu), dumplings, ravioli, and specialty items like Cafaberry coffee bars. Supporting services include coffee ground collection for businesses, educational workshops (mushroom cultivation, exotic mushrooms, farm tours), motivational speaking, and the Mushroom Master/E-learning programs for aspiring circular farmers. The business also operates retail gift packages and cultivation supplies. All products emphasize local Rotterdam production, circular waste valorization, and plant-based nutrition.

Differentiator

Problem solved

Functional benefit

Brands

• KoffieFris: A concept under Rotterzwam that produces circular soap products made from rescued coffee grounds from Rotterzwam's partner relationships.

Products and services

• Paddenstoelen Growkit Oesterzwammen
• Oesterzwammen (Fresh Oyster Mushrooms)
• Lion's Mane - Pruikzwam (vers)
• Oesterzwam Bitterballen - 100% Plantaardig
• Oesterzwam Kroketten - 100% Plantaardig
• Five Spice Fungi Dumplings
• Paddenstoelen Shoyu
• Rotterzwam Ravioli
• Koffiedik Ophalen Dienst (Coffee Grounds Collection Service)
• Workshop Oesterzwammen Kweken
• Workshop Exotische Paddenstoelen Kweken
• Rondleiding op de Kwekerij (Farm Tour)
• Mushroom Master Program
• E-learning Programma
• Inspirerende Spreker (Inspirational Speaker)
• Cadeaupakketten (Sustainable Gift Packages)
• KoffieFris Body Scrub

Quantifiable outcome

• 419,840 kg coffee grounds rescued from incineration since 2013
• +4 more outcomes

Named customers14 records

Segments5 records

Ideal customer profiles5 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration4 records

Feature4 records

Partnerships

13 partnerships are on record, tiered core and minor.

• ge-zwam (Gezwam)coreStrategic or Co-development Partner · 1 January 2025Regional franchise partner establishing a mushroom farm in the Den Haag region (Schipluiden) using the Rotterzwam method. Will provide fresh mushrooms and process some into snacks (bitterballen, kroketten) for the Haaglanden region. Planning crowdfunding in 2025.
• SPOROcoreStrategic or Co-development Partner · 1 January 2024SPORO is establishing a circular substrate factory under license from Rotterzwam to scale up the sterilization and cultivation technology developed through the Kansen voor West program. SPORO will operate the production facility while Rotterzwam provides the methodology and continues operating its own mushroom farm.
• Fermi FoodscoreStrategic or Co-development PartnerCollaboration to create Paddenstoelen Shoyu - a fermented mushroom sauce made from oyster mushrooms and shiitake. Both companies work with local ingredients and food chain waste streams. Product developed and sold through Rotterzwam.
• Dutch DumplincoreChannel Partner/ Reseller/ DistributorArtisan dumpling manufacturer producing Five Spice Fungi Dumplings using Rotterzwam's oyster mushrooms. Only dumpling factory in the Netherlands, providing manufacturing capacity for this product line.
• Nieuw Sociaal Werk (NSW)minorImplementation/ SI/ Consulting PartnerSocial work organization that assembles growkits in Rotterdam, providing employment opportunities for people with a distance to the labor market. Supports Rotterzwam's social impact mission.
• The Soap FarmminorChannel Partner/ Reseller/ DistributorDutch soap manufacturer producing KoffieFris body scrub products using coffee grounds collected by Rotterzwam. Products are vegan, plastic-free, made in the Netherlands.
• Kaffe BuenominorOthersDanish company providing coffee oil as an ingredient in KoffieFris body care products. Coffee oil is a circular byproduct that Rotterzwam sources for its body scrub line.
• JDE (Jacobs Douwe Egberts)minorGTM or Marketing PartnerCoffee company that engaged Rotterzwam early on to collect coffee grounds from their business customers in the Rotterdam region, validating the business model and providing market access.
• BlueCity (formerly Tropicana)coreStrategic or Co-development PartnerCircular economy business park in Rotterdam where Rotterzwam was founding tenant 2013-2017. Co-founders served as Blue Economy officers. Rotterzwam continues to be part of the BlueCity ecosystem and supplies products to businesses there.
• Universiteit WageningenminorStrategic or Co-development PartnerResearch partner in the 'Terug naar de Bodem' (Back to the Soil) project investigating the effects of coffee grounds on soil, conducted with the Louis Bolk Institute.
• Louis Bolk InstituutminorStrategic or Co-development PartnerResearch partner in 'Terug naar de Bodem' project studying the agricultural value of spent coffee grounds as fertilizer.
• Fryslan Fungi, Fungi Factory, Zuiderzwam, Zwamburg, Versfabriek, C-zwam, Zernike ZwamminorChannel Partner/ Reseller/ DistributorRegional growkit production partners in the Netherlands producing localized versions of the growkit under the Rotterzwam method, expanding reach and supporting circular mushroom cultivation network.
• Diverse Regional PartnersminorChannel Partner/ Reseller/ DistributorInternational expansion through partners including Beyond Coffee (Denmark) and Noah ecoliving (Spain) producing growkits in their regions using the Rotterzwam methodology.

Scale indicators9 records

Recent moves8 records

Expansion highlights8 records

Direct peers

• North Spore: US-based mushroom supply company selling spawn, substrates, grow kits, and cultivation equipment with strong e-commerce and educational content. Comparable to Rotterzwam's cultivation supplies (spawn, perforated bags, calcium carbonate) and education offerings.
• Zuiderzwam: Amsterdam-based urban mushroom farm that, like Rotterzwam, cultivates oyster mushrooms on coffee grounds and other urban waste streams using a circular-economy model. Listed as a Rotterzwam regional growkit production partner, indicating direct methodological and operational overlap.
• Mycopolitan: US urban specialty mushroom farm in Philadelphia focused on restaurant and retail supply of fresh gourmet mushrooms. Comparable to Rotterzwam's fresh oyster and Lion's Mane wholesale and HORECA distribution model.
• Smallhold: US-based indoor urban mushroom farm operating a network of growing macrofarms with subscription and wholesale distribution to restaurants. Comparable business model to Rotterzwam's B2B coffee collection + HORECA wholesale motion, scaled to the US market.
• GroCycle: UK-based mushroom cultivation company selling growkits and operating mushroom farming training programs. Directly comparable to Rotterzwam's growkit business and Mushroom Master / e-learning programs, with similar e-commerce-led GTM.
• Back to the Roots: US-based CPG company best known for mushroom grow kits sold through retail (Whole Foods, Target, etc.) and online channels. Directly comparable to Rotterzwam's growkit e-commerce and physical retail partnerships (Dille & Kamille, Bol.com).

Others

• Kaffe Bueno: Danish circular-economy company extracting coffee oil from spent grounds for cosmetics and nutraceuticals. Already a Rotterzwam partner supplying coffee oil for KoffieFris body scrub; adjacent rather than competitive, but operates in the same coffee-waste ecosystem.
• BioBean: UK-based circular-economy company that upcycles spent coffee grounds into biofuels and biochemicals. Adjacent ecosystem player to Rotterzwam's coffee-ground valorization model, though addressing different output markets (energy vs. food).
• BlueCity: Rotterdam-based circular economy business incubator and hub where Rotterzwam was a founding tenant 2013–2017. Functions as ecosystem partner rather than competitor; relevant for understanding Rotterzwam's circular-economy positioning and network.

Emerging players

• Fungi Academy: Online mushroom cultivation education platform offering courses and community for aspiring growers. Comparable to Rotterzwam's e-learning program (mushroom-cultivation.com) and Mushroom Master in-person training.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights6 records

Customer concentration

• Xx.com/RotterZwam
• Facebookfacebook.com/Rotterzwam
• LinkedInlinkedin.com/company/rotterzwam

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Rotterzwam