Beer Yeast Fermentation Series

Our Beer Yeast Fermentation Series is an experimental coffee collection that explores the influence of beer brewer’s yeast when introduced into the coffee fermentation process. The project was initiated by our Director of Coffee Freda, a sour beer drinker, whose curiosity around fermentation led to discussions with our partners in El Salvador on bringing the two together, adding another layer to our experiments with coffee processes. While we’ve previously explored stout-like coffee beers, this project shifts focus to the yeasts themselves, not the beer styles.  

Producer Carlos Pola has helped us bring this curiosity to life. Carlos has been at the forefront within the industry with regards to innovative coffee processing, and we have proudly worked with him for more than a decade, making him the perfect partner to collaborate with on this project. The collection comprises four lots of the same variety, grown on the same farm and processed under the same anoxic natural conditions, each inoculated with different brewer’s yeast strains that Carlos sourced from a brewery in San Salvador. One lot was then taken a step further through a souring process. The outcome is a clear demonstration of how each strain shapes flavour, structure, and aromatics.

Belgian Ale 

Inspired by craft beer brewing, this coffee was fermented with Belgian Ale yeast, producing a juicy, fruit-forward cup with the spice and fruit notes typical of Belgian and Trappist-style ales. 

Flavour notes: Passion Fruit, Pineapple, Lemonade. 

Profile: Juicy, fruit‑forward and sparkling. 

London Ale 

This coffee was fermented using London Ale yeast, known for producing the fruity esters found in many English-style ales. 

Flavour notes: Raspberry, Nectarine, Brown Sugar. 

Profile: Rich, bright and syrupy, with a clean finish. 

Kveik Voss 

Kveik Voss is a Norwegian farmhouse yeast culture preserved since the 1980s. In this lot, it adds lifted aromatics and refined fruit notes. 

Flavour notes: Apricot, Ginger, White Wine. 

Profile: Juicy and energetic with a polished acidity. 

Kveik Voss + Philly Sour 

This coffee underwent a sour fermentation using Philly Sour yeast, a lactic acid-producing strain developed in Philadelphia, followed by a second fermentation with Norwegian Kveik Voss yeast. 

Flavour notes: Strawberry, Mango, Muscovado Sugar. 

Profile: Deep, tropical and subtly sour, with a structured, creamy body. 

The Beer Yeast Fermentation Series is available as a limited-edition tasting box, featuring four 50g samples so you can explore each coffee side by side. Each coffee is also offered in our standard 250g bags. 

To mark the launch, we’re hosting coffee and craft beer tasting sessions on 22nd January across our Scoresby Street, Cornwall, Bristol and Edinburgh locations. Led by our brilliant education team, guests will experience a guided side-by-side tasting of all four coffees and their beer counterparts, exploring how brewer’s yeast shapes complexity and flavour in both.