Growing high-quality coffee is not easy. It requires a lot of dedication from the producer, and there are a huge number of variables that influence the cup quality of the final product. 

One of these many variables is cherry ripeness. It’s accepted across the industry that fully ripe cherries produce higher-scoring coffees.

But what if we could extract more quality from unripe coffee cherries? What would this mean for consumers? How would it taste, and would there be any other benefits?

To learn more, I spoke with stakeholders from all across the coffee supply chain. Read on to find out what they told me.

You might also like our article on how microorganisms affect fermentation.

Cherry ripeness and cup quality

Lucas Venturim is an award-winning specialty coffee producer and the director of Fazenda Venturim in Espírito Santo, Brazil. Fazenda Venturim grows high-quality or “fine” robusta, which has been cultivated and processed to a high standard to create desirable flavour profiles. 

However, Lucas says that no matter the species, unripe cherries produce cup profiles that aren’t as sweet and complex. 

“When the fruit isn’t fully ripe yet, it hasn’t developed all of the potential sugars,” he explains. “Because it hasn’t converted all its energy into sugars, the aromas and flavours don’t reach their full potential.”

Despite this, it’s not always easy for producers to harvest every single cherry at optimum ripeness. 

“We never manage to harvest all the fruits at the ideal maturation point,” he says. “Instead, you have a window, which we call the ‘harvest window’.

“Even if you dedicate 100% of your time to picking all the cherries at the right point, in the absolute best case scenario, some fruits will still be picked before or after the perfect point.”

Professor Flávio Borém has been teaching at the Federal University of Lavras (UFLA) in Minas Gerais, Brazil for almost 25 years. He is respected nationally and internationally as an authoritative voice on coffee science.

“Final cup quality is directly related to the proportion of ripe and unripe fruits at the time of harvest,” he says. “The higher the percentage of unripe fruits, the greater the astringency; the presence of unpleasant flavours (such as herbaceous and peanut notes) also increases.”

Health benefits of coffee consumption

There can be no doubt that consumer demand for higher-quality food and beverage products has grown in the last few years. A report by YouGov America claims that 80% of millennials in the US state that quality is a key factor when buying food and beverages. 

And while this change can be attributed to a number of factors, health and wellbeing arguably top the list. According to Mintel, a staggering 78% of US consumers believe that eating healthy food improves their emotional wellbeing.

This trend isn’t just limited to the US, however; it’s becoming steadily more prominent all around the world. Isao Takahashi is the General Manager of the CM Department Raw Procurement Division at UNICAFE Inc., a Japanese coffee roaster. 

He says: “Lifestyle-related diseases such as cancer, cardiovascular disease, and diabetes are deeply related to the causes of death among Japanese people, and we believe that prevention of lifestyle-related diseases is a very significant theme as a background of the growing population of elderly people.” 

Isao also notes that coffee is increasingly being recognised as a healthy beverage. “Many studies have shown that drinking coffee is associated with the prevention of those lifestyle-related diseases,” he adds. “We have therefore been focusing on the [role of the] polyphenols contained in coffee.” 

Professor Borém concurs: “The beneficial health effects of coffee are generally attributed to its high antioxidant activity, which is mainly associated with its high levels of polyphenols.” 

One such example of these polyphenols is chlorogenic acid, which naturally occurs in coffee. At high levels, chlorogenic acid causes undesirable, highly astringent flavours in the cup. However, it has also been linked with a number of notable health benefits. 

First and foremost, chlorogenic acid is an antioxidant. Antioxidants prevent cells from being oxidised, which in turn halts free radical production. Free radicals (unpaired and unstable atoms) left to “roam” the human body are associated with a number of long-term diseases, such as arthritis, heart disease, and Alzheimer’s.

Alongside this, chlorogenic acid is also a natural anti-inflammatory, and has been shown to inhibit the hepatitis B virus.

What about unripe cherries?

Despite the unpleasant flavours that unripe coffee cherries typically produce, they are safe for consumption and even healthier than ripe cherries in some areas.

Professor Borém says: “Even though the beans from immature cherries have been classified as defective for decades, they are healthy and represent no harm to health. 

“This is unlike beans that have been damaged by pests or diseases, which can have lower cup quality and also pose health risks to the consumer.”

Furthermore, he adds: “Coffee beans from immature fruits have a greater amount of active antioxidant compounds than those from mature fruits.”

A cutting-edge nutraceutical coffee project

Matthias Koenig is the Head of Agri Value Chain Specialties Businesses at Syngenta, a world-leading agricultural supply company. Nucoffee is a coffee platform operated in Brazil by the Syngenta group. 

Matthias explains that together with stakeholders from across the industry, Nucoffee launched a study to explore the potential for unripe coffee cherries.

He says: “The idea has always focused on the connection between Brazilian coffee producers and international buyers, with a view to improving the value chain, adding transparency, and supporting the development of quality and sustainability on farms.”

Isao adds: “Since chlorogenic acid has a tendency to decrease during the roast, we wondered if it was possible to produce green coffee beans [which were] rich in chlorogenic acid in coffee-producing countries like Brazil, which was our focus at the time.” 

After five years of research, Matthias says that the study has developed a unique, experimental post-harvest technique which can improve the quality and complexity of the beans harvested from unripe coffee cherries. The project itself was an idea from Professor Borém, as he developed the technology which forms the basis of the technique.

Syngenta invested in this project not just to add value and quality to the final product, but also to support farmers. There is generally only a short window when coffee cherries can be harvested at their ripest, and having pickers repeatedly patrol the same areas is not feasible or cost-effective.

The idea behind the project is simple. Unripe coffee beans are naturally more astringent, but also higher in antioxidants. By using this unique technological innovation to counteract the astringency and create a more desirable cup profile, you can use unripe cherries to produce a coffee which is more marketable to health-conscious consumers.

While initially the method was used with a ratio of 70% ripe to 30% unripe cherries, it has since been refined. Using this unique technology, it is now possible to achieve good results with a full batch of 100% unripe coffee cherries.

Professor Borém says: “The post-harvest technology developed at UFLA and licensed to Syngenta Nucoffee was able to raise the cup score of the treated coffee by up to five points.

“Studies have shown that this makes the cup sweeter, slightly acidic, and gives it more complex flavours, often of fruits or spices.”

Lucas Venturim, who has contributed to the research by performing experiments on his farm, says he was surprised with the results. “We achieved an exceptional improvement in quality,” he tells me.

“In the first experiment, we used an untreated coffee as a control group, and it scored 78 points. The coffee that was treated, however, scored around 85 to 86. It’s an incredible increase. 

“But what’s really interesting is that it generated a sensory profile that was totally different from anything we’ve ever had on the farm,” he adds.

Matthias says: “The high antioxidant activity of unripe coffee cherries has been known for a while, but the ability to manage the sensory profile of these coffees is unique.”

Finally, Isao adds: “While we are still in the process of carefully considering the superiority of the high chlorogenic acid levels, the quality of nutraceutical coffee was high because of the distinctive, bright acidity, sweetness, clean taste, and pleasant finish, which altogether reminded us of the quality of specialty coffee.”

What could this mean for the supply chain?

From a producer’s perspective, Lucas says this method could be really helpful, as it’s virtually impossible to harvest every single cherry at its ripest point. 

He says: “The idea is not to encourage everyone to harvest unripe cherries with this process, but rather to take advantage of the inevitable proportion of unripe cherries, and therefore get more profit out of them.

“Then, if the average income of the farm improves, it will be better equipped to make investments and remunerate those who work on it. I think it’s revolutionary for that reason: you start taking a product that until then had been undervalued in the market, and realise you can turn it into a new product which can reach a really high value.”

And the evidence is there, according to Matthias. He says: “We have observed the reaction of potential buyers and other value chain participants, and the feedback has been very exciting. 

“There are several ways to apply this technique and use it to make coffee healthier, and more sustainable, while also creating new market segments for Brazilian coffee,” he explains.

Isao adds: “This is truly an innovation. The value of the coffee will rise, and if unripe coffee cherries can [increase in value], we can expect positive effects, including better quality of life for producers, more motivation to grow coffee, and continued quality improvement.”

Professor Borém says that he finds the research to be groundbreaking: “I consider the most important aspect of this research to be the challenging of an old paradigm that most people did not believe was possible. 

“It is now possible to explore the health benefits and quality of coffee at the same time,” he concludes.

Across the coffee sector, producers face no shortage of challenges to maintain profitability. One of them is the question of what to do with unripe cherries, as historically, every green cherry harvested represents lost potential income.

However, a world where unripe coffee cherries could yield better-quality, more marketable coffee could be much more sustainable for the producer, as well as beneficial for others across the supply chain.

Enjoyed this? Then read our article on nature vs nurture and what has the greatest effect on coffee quality.

Photo credits: Fazenda Venturim, Fazenda Canto Alegre, and Sítio Santa Edwirges

Perfect Daily Grind

Please note: Nucoffee is a sponsor of Perfect Daily Grind.

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