Fermenting unique flavours from coffee beans

The Nestlé research team has gained a deeper understanding of coffee post-harvesting conditions, and their impact on the quality of coffee.

The taste of a cup of coffee is the result of much more than perfect roasting and brewing. Many steps along the value chain contribute to highlighting unique flavours and creating a differentiating and authentic coffee experience.

It all starts with farming high-quality coffees and growing them in their native environment where they can reveal their natural characteristics and flavours.

It is also about harnessing post-harvesting practices that lead to a fine modulation of the coffee quality and to expand the range of natural flavours and aromas of the final brew. One example of such post-harvesting practices is fermentation.

Fermentation is the natural process that takes place at the farm just after coffee cherries are picked. It starts spontaneously thanks to the activity of microorganisms that are naturally present in the environment and on the green coffee beans. Controlling this fermentation is an important post-harvesting practice that is increasingly being adopted in coffee production, although it has been used for many years in other categories of the food industry such as yoghurt and cheese.

Nestlé Research scientist Cyril Moccand said the team engaged in a deep scientific investigation into the microbial ecosystem involved in coffee fermentation and the range of flavour molecules in the coffee beans.

“This enables us to highlight the flavours that are being naturally produced during fermentation and that are maintained in the final cup,” Moccand said.

“For the first time we were able to reveal a direct link between fermentation and the flavour attributes of a coffee brew.”

This knowledge can be leveraged to tailor specific fermentation conditions to different coffee varieties, allowing for the ability to highlight new distinct natural flavours and sensorial notes and to consistently maintain their quality, while avoiding raw material loss due to uncontrolled fermentation.

The Nespresso limited edition La Cumplida Refinada coffee, produced in small coffee farms in the Matagalpa region in Nicaragua, is the first coffee to leverage the company’s scientific findings that link fermentation with sensory properties. Through hundreds of fermentation trials, Nestlé researchers and local farmers have been working side by side to identify and apply tailored fermentation conditions to the harvested coffee beans.

“The team found that while carefully monitoring the natural process, it was possible to unlock a differentiated sweet and light coffee profile with wild fruity notes,” said Frédéric Mestdagh, Coffee Research Manager at Nespresso. “We successfully scaled this post-harvesting process to larger quantities to produce this limited-edition coffee, ensuring the same sensorial quality in each cup.”

The company said mastering this on-farm post-harvest fermentation technique brings smooth notes of candied cherry and pomegranate to the Nespresso La Cumplida Refinada coffee.

Image credit: ©stock.adobe.com/au/Subbotina Anna