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EROI Drink (エロいドリンク) is an energy drink made from Japanese Knotweed, an invasive alien plant pervasive in the Netherlands. We especially focus on sourcing unpolluted strains by working with water management companies and a nature conservation organisation.

The drink is named after the term "EROI" which stands for Energy Return on Investment, a measurement increasingly becoming critical in an era ever more finite. "エロい (Eroi)" simultaneously implies romantic in Japanese, representing the Utopian ecology conceived around the drink.

The unwanted nature of an invasive species puts itself in a similar position to the wind or the sun, an abundant energy source. When combined with zero-emissions transport, an extremely high EROI beverage can be produced, namely, the EROI Drink.

Non-agricultural, Invasive, Unpolluted knotweed sourced from Evides Huijbergen, May 2021

The project was initiated at the beginning of the pandemic in April 2020, with a few batches of unpolluted Japanese knotweed delivered from Melle van Overbeek, a ranger from Rotterdam-based water management company Evides. During this time TOFU established a basic juicing method referring to a roughly described recipe of a knotweed lemonade found in a decade old Japanese agricultural magazine.

Since March 2021, TOFU has been going into the actual harvesting areas managed by Evides; we visited several water catchment areas seeking for young shoots of knotweed. On paper, we aim to provide a better control method for Japanese knotweed for water management companies; harvests are merely waste produced in this process. Therefore, the resulting energy drink is a by-product and there is no dedicated supply chain built for it.

Yoshinari Nishiki hitching a ride with Evides ranger Melle van Overbeek heading to water catchment areas, March 2021

One of the water catchment areas is located in a forest next to an under construction residential area. In order to gain access to the restricted zone without a special key, you need to pass through a football pitch and cross a small ditch.

Harvesting knotweed with Ronald Boer from Amsterdam collective De Onkruidenier, April 2021

In 2021, TOFU further developed the drink recipe and also applied a process called maceration. With the improved juicing method, a two-bottled sample drink was complete. The main bottle is made with knotweed juice and knotweed syrup; the small bottle is the herbal extract derived from the dried root.

EROI Drink (sample) tested by Tim Terpstra and Marijke Cobbenhagen at the Grey Space in the Middle, The Hague, May 2021

The collaboration has been expanding further; now TOFU is in contact with a weed control company that works for four water management companies. Currently, knotweed harvested in the fields managed by Brabant Water is collected in a place called Sliedrecht, approx. 30km away from Rotterdam. TOFU deploys a light-weight manual cargo bike specially made by Number5unexplained and manages biweekly delivery of adult knotweed without emissions.

TOFU with a cargo bike carrying six crates at Verheij headquarter in Sliedrecht, June 2021

With the aid from Urban Greeners, TOFU also got our hands on FSC-certified knotweed that grows in nature reserves managed by Staatsbosbeheer in Almere.

TOFU was guided to a FSC-certified knotweed spot by senior ranger Johan van Onna from Staatsbosbeheer Almere, June 2021

On 28th July (wed), TOFU is leading a small group of people to make an experimental exercise out of knotweed cutting. A specially customised knotweed apron and tool were developed with the help of studio colleagues Teun Vonk and Maurik Stomps.

Special knotweed apron and tool, both prototypes, Rotterdam, July 2021

The calligraphy of the final bottle design was created by Taiwanese artist Chang Chia-che. The typeface for the drink was kindly provided by London-based designer Charlotte Taillet.

Bottling and labelling at TOFU HQ, July 2021

Delftsestraat 33-202, Rotterdam 3013 AE

2021 TOFU Attribution 4.0 International (CC BY 4.0)
Yoshinari Nishiki
alexojisan · EROI Drink