The Science Behind Controlled Fermentation, A Summary

Recently, we’ve had the great pleasure to host a very special webinar with Nucoffee Syngenta and two extraordinary guests, a microbiology expert – PhD Rosane Schwan and a coffee industry superstar – Silvio Leite. We’ve learned a lot about the science and technology behind the controlled fermentation processing method and we would like to share it with you! *If you’ve missed the webinar, we invite you to watching it on our YouTube channel – link to the video *

We’ve been a part of this project for the last 3 years and had a pleasure to see it evolve even before the first crops were made. During this time we made several tests on the coffee and brought opinions from the roasters back to UFLA to help them choose the right microbiota and shape the process according to the customers’ needs. 

Firstly, it’s significant to mention that controlled fermentation is a science-based processing method, meaning that the producers can repeat it following specific instructions to receive coffee beans of the same high quality. That makes our fermentation a reliable process allowing us to replicate the excellent sensory results with each crop and learn from it. That is the reason we call it controlled fermentation. During the webinar, we talked more about the process step by step. PhD Rosane Schwan explained how for 25 years, she and her team of professors and students at UFLA have studied the microbiota present in coffee cherries to establish the exact yeasts and bacteria acids that enhance the coffee flavour. Thanks to all of the farmers that took part in the project and tested the controlled fermentation process, the scientists had a chance to research the outcomes like sensorial alterations and quality improvements.

“Fermentation is a natural process that occurs in coffee fruit, all it needs is humidity, sugars and microorganisms to do so. Meaning we can still make and have been making good coffee without controlling the processing methods but the controlled fermentation allows us to increase a specific microbiota, hence increasing specific flavours and quality.” – PhD Rosane Schwan

During the research, PhD Schwan has managed to establish that the yeast and bacteria present in the coffee pulp are dominant in producing compounds like lactic acid, citric acid, higher alcohols etc that stay in the coffee bean after roasting and allow to sculpt the sensory profile according to the needs. The method works only with fully ripe fruits, meaning that the farmers need to use selective harvest in order to proceed. With all that knowledge, the team created a step by step controlled fermentation process:

But what are the advantages of a controlled fermentation process? 

The process gives a producer full control over the quality of the fermentation and the number of microorganisms placed inside of the bioreactors. Additionally, it increases the sensorial quality of the beverage, accelerates the drying process and even gives the producer the ability to create a specific sensorial profile. 

After gathering all the data, the team created the Culture Collection of Agricultural Microbiology with more than 2000 strains which can provide the diversification and intensification of flavours and aroma. At the end of each year, scientists expect a huge base of profiles to attain the demand of each consumer. 

“It doesn’t just increase the quality but also diversifies the profiles and allows the consumer to choose their perfect coffee.” – PhD Rosane Schwan