June 25, 2020

Nature vs Nurture: What Has The Greatest Effect on Coffee Quality?


By how many points can a producer increase their coffee’s cupping score? 

Good farming practices will highlight a coffee’s best features and reduce the risk of defects. But with certain coffees, there may be an upper limit to how much the quality can be improved. 

Producers, you need to be aware of this in order to best allocate your resources, target the right market, and improve your return on investment.

Lee este artículo en español Naturaleza vs. Cultivo: El Efecto en la Calidad Del Café

Credit: Julio Guevara

Nature: The Coffee Plant’s Intrinsic Quality

Some coffee plants will always yield more or better fruit than others. Part of this is due to the attributes of the individual plant and its parents: you can take two coffee plants, both of the same variety and grown in the same plot, and still find differences in their strength, productivity, and cup score.

That being said, the plant species and variety will give a strong indication as to the coffee’s inherent qualities. For example, Geisha coffee has become famed for its delicate, tea-like body and jasmine aroma. It’s adored by specialty coffee roasters and consumers alike. 

Yellow Bourbon typically produces high-quality coffee at a medium yield, although it’s susceptible to pests and diseases. Meanwhile, Catuai and Caturra are associated with medium-quality coffee. 

Maria Julia Pereira owns two farms in South of Minas, Brazil, where she focuses on specialty coffee. She believes that the terroir, coffee variety, and post-harvesting are the three keys to producing quality coffee.“In my opinion, the terroir is, let’s say, 40%, another 30% is variety, and finally there’s the handling and care in post-harvesting,” she says.

Read more in Geisha vs Bourbon: A Crash Course in Coffee Varieties

A coffee’s variety cannot be isolated from the location. Some plants grow better at cooler temperatures, while others are more suited to hotter environments. Coffee grown at cooler temperatures generally has a lower yield but more promising flavour profile. Pests are also less of a risk at cooler temperatures. Many high-quality plants are extremely sensitive to external factors, such as being farmed at the wrong elevation or in the wrong soil. There is a reason that Maria Julia values terroir so highly.

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Credit: Fazenda Pinheirense

Terroir & Other Environmental Factors

Terroir, a word adopted from French and used in the wine industry, refers to every aspect of where the coffee is grown: the soil condition and qualities, climate, sun exposure, and more. Jean Faleiros of Fazenda Eldorado, an award-winning farm in South of Minas Gerais, Brazil, describes terroir as “fundamental”. 

Read more in What is Terroir & How Does It Affect Coffee Quality?

“The quality is very much linked to ripening,” he says, “and the later the ripening, the more chemical compounds and sugars there are, and the better quality the bean will grow to be. He adds that “Here [on Fazenda Eldorado], we are in a region of 1,200–1,300 m.a.s.l. We have a very late harvest here. This greatly improves the quality of the coffee.”

Maria Julia also considers elevation and microclimate important. She tells me, “I have a plot at 1,200 m.a.s.l. in an elevated position facing the sun. This plot never disappoints me. It gives me a very sweet drink with a strong chocolate flavour.”

However, a lot can be well-suited to coffee farming but poorly suited to the producer’s variety or preferred farming methods. For example, the amount of shade coverage producers use should be calculated based on the hours of sunlight and moisture levels. This will create stress-free conditions for the coffee plants, helping them to grow healthy. 

Jean says, “A friend of mine… They produce coffee at 900 m.a.s.l. They produce specialty coffee but they created a microclimate for that. They produce shade coffee and they do all the organic work to improve the condition of the fruit too.”

However, farmers who wish to use certain types of shade trees, whether to ensure economic sustainability or a profitable additional income, may find that this crop does not neatly fit in with the requirements of the coffee variety and farm location.

Other steps can be taken to mitigate less-than-ideal growing conditions: fertilisation can replenish soil, while on bigger farms, irrigation can tackle the issues caused by long dry seasons.

Climate change, however, is making environmental conditions harder than ever to control. Long droughts and out-of-season rain are increasingly common. A dry season with too much sun exposure can not only damage the harvest but also weaken the plants, reducing their ability to develop healthy fruits in the future. Harvest rains can damage the drying process. Both situations will influence quality.

Credit: Fazenda Pinheirense

Farm Management & Harvesting

While certain varieties tend to produce better quality, high scoring coffees, this doesn’t mean that others cannot. Lucas Venturim is a producer from Fazenda Venturim, Espírito Santo, Brazil and has developed a specialty-grade canephora (robusta) coffee. He feels that what makes a coffee special isn’t necessarily its species or variety, as all coffees have potential.

For him, farm practices are what determine a coffee’s quality. “I don’t mean to say that all varieties are the same,” he continues, “but they all have the potential to do a good job. They all have the potential to become a specialty coffee.

“Of course, it will be much easier to produce a specialty coffee with a Geisha than with a Catuai. But I have already had Catuais with 87, 88 points too… and so it is possible that I have Geishas below 80 as well.”

Careful planting, fertilisation, pruning and stumping, weeding, inspections, manipulation of shade coverage, harvesting, and more – all of these have an impact on how well the coffee grows.

Poliana Perrut is a fine Robusta producer and owner of the award-winning farm Chácara Paraná in Novo Horizonte Rondônia, Brazil. Yet her coffee hasn’t always been good. A few years ago, she tells me, the entire region used to “harvest very early” due to the lack of milling equipment and dryers, so that most of the coffee was green and full of defects. “There were 400 defects, 600 defects and… we saw it as a good coffee,” she says.

Now, however, things are different. “Many producers are building their own patios, their greenhouses, and working with raised beds, which is a movement that Poliana didn’t think would ever arrive in Rondônia – but it did.“We are in this evolution of coffee now, in which producers are harvesting increasingly ripe coffees, and already have their post-harvest structures on the property to improve this quality of the coffee produced.” 

She attributes these improvements in infrastructure and harvesting practices to her coffee’s good cup score. Selective harvesting can improve a coffee’s overall sweetness by ensuring that only ripe cherries are included in a lot. The riper the cherry, the better the sweetness; unripe cherries, meanwhile, can lower a lot’s overall sweetness. And sweetness is worth up to 10 points in the SCA’s Arabica coffee green grading formula.

Jean emphasises the importance of fertilising and soil management, too. “From the moment [the coffee] blooms, if you don’t do all the chemical treatments on it… Let’s put it like this: the plant, the coffee tree, is a mother. And the fruit is the child. So if you don’t give the mother the condition to give the child the right milk, he will go hungry.” And, he adds, if the tree is hungry or “suffering from stress, it will not produce good fruit” and “you will not be able to produce specialty coffee”. 

Emma Sage, Coffee Science Manager at SCA, wrote that Arabica coffee is “perhaps one of the more stubborn and sensitive of agricultural commodities… It has not had time to evolve to new climates and conditions. A C. arabica coffee plant in Indonesia, or Brazil, or Jamaica still grows best under the ideal conditions that its ancestors learned to love in the shaded understory of tropical forests in East Africa.”

While she acknowledged that the required soil management will vary according to the terroir, some degree of fertilisation is nearly always necessary in order to keep coffee plants healthy and productive. And an unhealthy coffee plant cannot produce quality fruit.

Credit: Fernando Pocasangre

Post-Harvest Processing: Sorting, Fermentation, & Drying

Perhaps the riskiest moment for maintaining quality comes after the coffee has already been harvested. 

Sorting is a time-consuming but important step, as removing defective coffee beans can significantly improve a coffee’s quality. According to SCA green grading standards, one primary defect in a 350g sample will disqualify the lot from achieving specialty status. As for secondary samples, a maximum of five per sample can be accepted.

Most coffee buyers and roasters check green samples for defects before sample roasting, cupping, and evaluating them. The presence of defects will affect not just the cup score but also the price offered.

Meanwhile, it is important to act quickly to avoid uncontrolled fermentation. While fermentation is an intrinsic part of coffee processing, it is notoriously difficult to control. When poorly done, it leads to inconsistent flavours and even mould development. It threatens not just the quality of the coffee but also the consumer’s health.

Margaret Fundira is a Microbiologist and Product Manager at Lallemand, which produces the Lalcafé™ yeast brand – a product that consists of five yeasts specifically selected for coffee processing, in order to help coffee producers better control fermentation in washed and dry processing. She says that the wide variety of microorganisms present during uncontrolled fermentation can dictate the flavours and aromas in the final product, which is why it’s important to use specific yeasts selected for coffee processing.

“I want to control the fermentation, because, remember, there’s always fermentation taking place,” she says. “It can either happen without you controlling it, in which case, the odds are that it can be good, it can be great, or it might not be, depending on the microorganism that is present at the time of harvesting, and those can vary from season to season or even from week to week.”

Poliana used to allow her coffee to ferment in an uncontrolled manner, before experimenting with anaerobic fermentation and yeasts. She says that back when it was uncontrolled, “it was a negative fermentation”. However, by controlling the process with yeasts and ensuring the coffee dries evenly and thoroughly, its quality increased by 3 to 4 cup points and she even won a competition.

Margaret adds that the exact strain of yeast can determine the types of flavours that are accentuated, although it cannot bring out anything that’s not already in the coffee. For example, while LALCAFÉ Cima enhances bright acidity and citrus notes, LALCAFÉ Intenso was selected to highlight “floral aromas, tropical fruits”, and overall complexity.

Jean has experimented with different strains of yeasts, including LALCAFÉ Oro and LALCAFÉ Intenso. He believes it’s important to choose the right yeast for the farmer’s goals. “[Intenso] completely changed the profile of the coffee…,” he says. “It seemed that I was drinking a coffee from Ethiopia.” 

He decided that even though Intenso made for “an excellent coffee”, he preferred LALCAFÉ Oro, as it increased the quality of his coffee from 86 to 88 points and improved its balance and finish. More importantly, however, the coffee flavour profile was still recognisably Brazilian. He felt that this was better for his target market. 

Margaret stresses the importance of considering the market over the difference in the cup score. “If you’ve been really doing all the right things [during farming and harvesting], nurturing your coffee, chances are that the differences from a score point of view might not be that huge, maybe even one or two points. 

Margaret says that you will notice a difference in the profile that is created. “You can then use your specifically selected coffee yeast to differentiate between the range that you have… And then the question is ‘Am I happy with that differentiation?’ or ‘Do I have different markets that I can target because I know this market likes more flavours like this?’ and so on. It’s really a tool that is available to producers that they can use to their advantage at the end of the day.”

Credit: Fazenda Eldorado

Nurture vs Nature: What Has The Biggest Impact on Cup Quality?

The coffee plant’s genetics have a huge impact on its strength, productivity, and resulting cup quality. But so do the terroir, soil management, harvesting practices, sorting, and control over fermentation. No single step can be overlooked.

As for which one has the greatest impact? Nurture can highlight nature’s intrinsic qualities, but it cannot work a miracle.

Coffee producers should understand the intrinsic qualities of the plants and their desired market, and then allocate resources appropriately. It may be worth investing fewer resources in weaker plants so as to focus more on stronger ones. Prioritise actions that will have the best return on investment, from selecting the right yeasts through to the time spent on sorting.

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All quotes from coffee producers have been translated from Portuguese. 

Header image credit: Fazenda Três Meninas

Please note: This article has been sponsored by Lallemand.

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