Coffee by-products
This is part of our series on upcycling.
Few foods or drinks inspire such devotion as coffee. Indeed, with over 11 million tonnes produced annually, coffee is often noted as one of the world's most traded commodities, second only to crude oil.¹
But however you drink your coffee—whether you savour a single-origin pour-over or rely on more utilitarian means to satisfy your caffeine fix—brewing it is incredibly wasteful. What we ultimately consume is essentially hot water that has briefly permeated its namesake roasted and ground-up bean. The remaining solid matter—the spent coffee grounds—is often discarded. However, these grounds are surprisingly rich in fibre, protein, lipids, and bioactive compounds, such as antioxidants and caffeine.² Despite their potential value, the majority of this by-product ends up in landfill.³
Yet, these grounds are far from waste. One increasingly well-established use for spent coffee grounds is as a substrate for growing mushrooms, while companies such as Kaffe Bueno are exploring their potential applications in pharmaceuticals and cosmetics. The grounds can also be upcycled into products for human consumption.
Coffee processing produces other by-products, too. The fruit that surrounds the bean—known as the coffee cherry—is commonly discarded and left to rot, despite being rich in polyphenols, dietary fibre, and natural sugars.⁴While it is sometimes dried and brewed as cascara (a dried fruit tea), much of its potential remains untapped. Another commonly overlooked material is coffee chaff—the thin, papery husk that flakes off during roasting and grinding.⁵
If an estimated 99% of the biomass involved in coffee production never makes it to the cup⁶, regardless of the precise figure, the reality is clear: an entire world of flavour, nutrition, and possibility is being discarded. Here, we present our culinary research into how we could better utilise coffee by-products.
Contributions & acknowledgements
Eliot wrote the article, with contributions and editorial feedback from Taylor and Josh.
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Endnotes
[1] Food and Agriculture Organization of the United Nations (2023) ‘Production: Crops and livestock products’, FAOSTAT.; the commodity stat comes from Pushpa S. Murthy and M. Madhava Naidu (2012) ‘Sustainable management of coffee industry by-products and value addition—a review’, Resources, Conservation and Recycling.
[2] Rocio Campos-Vega, Guadalupe Loarca-Piña, Haydé Vergara-Castañeda and B Dave Oomah (2015), ‘Spent coffee grounds: A review on current research and future prospects’, Trends in Food Science & Technology.
[3] Ibid.
[4] Andrea Heeger, Agnieszka Kosińska-Cagnazzo, Ennio Cantergiani and Wilfried Andlauer (2017) ‘Bioactives of coffee cherry pulp and its utilisation for production of Cascara beverage’, Food Chemistry.
[5] Ibid.
[6] Kaffe Bueno