Fruity fermented coffee could soon be mainstream

By Alice Clifford via SWNS

A new discovery could help fruity fermented coffee join the mainstream.

Speciality coffees are gaining traction in coffeehouses around the world - and now fermented coffee could bring a fruity taste to your morning cup.

This new drink gives off a raspberry-like taste and aroma which makes it stand out from the crowd.

But up until now what causes these sensations has been a mystery.

Now a team of scientists has found that six compounds contribute to the fermented coffee experience.

The new discovery could help increase the production of the drink and make it more readily available for everyone to enjoy.

Dr. Chahan Yeretziaz, the project’s principal investigator, said: “There are now flavors that people are creating that no one would have ever associated with coffee in the past.

“The flavors in fermented coffee, for example, are often more akin to fruit juices.”

As well as being tasty, the high demand for this unique coffee means fermented beans can fetch a high price, potentially benefiting farmers.

Preparing the beans also requires much less water than traditional methods, meaning it is better for the environment than your standard cup of coffee.

To find out what compounds make up the unique drink, scientists took arabica beans and divided them into three groups.

They prepared two of the groups using common processes used to make your average cup of joe.

However, for the third group the team fermented the beans.

To do this they took whole coffee fruits and fermented them in stainless steel tanks and infused them with carbon dioxide to lower the pH of the fermentation.

Unlike the other brews, the coffee made with fermented beans had an intense scent, smelling like raspberries with a hint of rose.

To find out what compounds made up these beans, they brewed coffee using each type of bean and analyzed the samples with gas chromatography (GC) sniffing.

The GC instrument separated individual components so each one could be identified.

As the compounds left the instrument, they went to a mass spectrometer for identification and someone smelt each one and described its scent.

The human nose can sometimes detect scents from compounds that are at such a low concentration, they’re unable to be picked up by mass spectrometry.

Yeretzian said: “Because the chemical signature doesn’t tell us how a compound smells, we have to rely on the human nose to detect the scent as each compound comes out of the chromatography instrument individually.”

This method can prove to be tricky as there is a subjective element to it.

Dr. Samo Smrke, a research associate in the lab, said: “We’re using people to detect scents, and everybody perceives flavors a little differently.

“But in this case, the panel was very consistent in the smells they described. So, what is traditionally considered a challenge was actually not an issue because the aromas were so clear.”

Although six compounds appeared to contribute to the intense fruity flavor, the team was only able to identify three of them.

These were 2-methylpropanal, 3-methylbutanal and ethyl 3-methylbutanoate.

The researchers from the Coffee Excellence Center at Zurich University of Applied Sciences now hope to identify the remaining compounds and judge the intensity of different flavors and scents.

They also aim to find out more about how these unique compounds form.

Potential factors could be farming practices, the variety of coffee beans, the microclimate of specific farms and the microbes present during fermentation.

Fermented coffee has become popular in competitive events due to its unique flavor.

The method was first introduced to the specialty coffee world in 2015, when the winning contestant in the World Barista Championship used it to prepare their entry.

However, with little knowledge available, some people have been concerned that it is difficult to distinguish between the genuine product and a regular cup of coffee that has been adapted to taste the same.

With more knowledge of these compounds, this issue can be resolved and make fermented coffee easier than ever to make.

With large-scale production, more people will be able to enjoy this distinctive flavour.

The researchers will present their results at the spring meeting of the American Chemical Society.

The hybrid meeting will be held virtually and in-person March 26-30 and will feature more than 10,000 presentations on a wide range of science topics.