What’s the problem with infused coffees?

Article by Sasa Sestic

Traditionally, coffee has been processed using three methods: washed processing, natural processing, and honey processing. In recent years, however, we’ve seen the emergence of some unconventional and alternative processing techniques.Between 2011 and 2015, Saša Šestić visited more than 200 coffee farms around the world and cupped hundreds of different lots. However, after realising that there were so many inconsistencies between coffees which had been processed using the same method, he looked to the wine industry to find a solution.

In this article, he explains how fermentation has changed the trajectory of coffee production, and why some farmers are “infusing” their coffees with other flavours. Read on to learn more.

You might also like our article about Saša’s documentary, The Coffee Man. 

sasa sestic with a coffee seedling


After cupping so many different lots and tasting inconsistencies across the same processing method, I was confused.

How could these coffees be looked after with the same care and detail, yet taste so different? Consistent quality, after all, was what so many specialty coffee producers were looking for.

In response, I started to collaborate with winemakers. This research led to my presentation of the first carbonic maceration (CM) coffee on the world stage when I competed at the 2015 World Barista Championship (WBC) in Seattle.

Following the success of my routine and wider experiments with CM, the Project Origin team and I participated in articles, interviews, and coffee seminars worldwide. This included the Re:co Symposium in Budapest.

After this, we started experimenting with the CM process on a more commercial scale. In 2015, Jamison Savage of Finca Deborah and Morgan Estate and I used it to boost the cup score of an 87.5 point Geisha beyond the 90 point threshold.

After seeing that this coffee commanded higher prices from buyers, Jamison started to use CM more widely across Finca Deborah. Not long after, Sam Corra placed second at the World Brewers Cup with a CM lot, helping to further raise the profile of the technique.

However, I started to wonder what would happen if we started to use this process on farms at lower elevations, to potentially add more value to their coffees. To test this, we purchased the Finca El Arbol farm in Nicaragua, at an altitude of around 1,100 m.a.s.l.

coffee beans drying


Since 2015, we’ve continued to experiment with carbonic maceration. Over the last six years, my colleagues have conducted over 350 different experiments at Finca El Arbol.

It hasn’t been easy, but we’ve taken a different approach to make CM coffees work at low elevations with common varieties like Catimor and Caturra. The results have been incredibly rewarding.

Following these experiments, we opened a larger CM fermentation mill in Nicaragua near the farm. This is not only used to process coffees from Finca El Arbol, but also to offer CM processing to our neighbours. The intention is to boost the region’s cup scores on the whole.

Several months on, we used the mill to produce lots from different farmers using common, lower-scoring varieties like Catimor and Caturra. Recently, two of these ranked in the top ten at the most recent Nicaragua Cup of Excellence competition.

Today, the CM process is used by producers across the Bean Belt. I co-own three coffee farms in Honduras, Panama, and Nicaragua, where we constantly research new and innovative coffee processing techniques in collaboration with Chr. Hansen in Copenhagen and Professor Dr. Chahan Yeretzian of ZHAW University in Switzerland.

We’ve worked with over 50 coffee farms in ten countries, using 50 different varieties, and carried out over 1,500 experiments to raise the profile of CM coffee.

fermenting coffee beans


In our experiments with carbonic maceration, we target specific microorganisms by controlling different variables during fermentation. These variables include tank temperature, environment, time, yeast and bacteria esters, and many more.

Doing so allows us to elevate the flavour profile of the coffee, raising its cup score and changing its taste in a specific way.

For example, in order to improve a coffee’s texture and to increase its creamy, buttery mouthfeel, we designed a style of fermentation that highlights the presence of microorganisms like Bacillus subtilis and Bacillus amyloliquefaciens. These microorganisms produce a final compound called acetoin, which is responsible for giving coffee a buttery taste.

But even so, there are limits to which flavours fermentation can produce.

At the 2018 Amsterdam WBC, I had the privilege of tasting other competitors’ coffees. One national champion offered me an espresso; as soon as I held it, I could make out a distinctive cinnamon smell. When I tasted it, the note of cinnamon carried through to my palate. It was like I had put an entire stick of cinnamon in my mouth.

I have tasted some really unique and rare coffees, but this one stood out. I asked the competitor about the process, and he told me that the cinnamon flavour was caused by a “special yeast” that reacted with the coffee to produce this particular taste.

In Boston in 2019, we saw another cinnamon coffee used in the Brewers Cup. Once more, the competitor told me the cinnamon flavour was achieved through the use of specific microorganisms during fermentation.

Both coffees came from the same country (Costa Rica), but were from a different farm, of different varieties, and processed differently. Yet they shared the same cinnamon taste.

Today, while we cannot be 100% certain, I believe that these cinnamon coffees and others like them have been artificially infused with this cinnamon flavour. Research strongly suggests that such an intense cinnamon flavour cannot naturally be achieved in coffee, no matter how it is processed or fermented.

coffee beans drying


You can easily infuse coffee with cinnamon yourself, even at home. All you need is a plastic tub, water, green coffee beans, and cinnamon sticks. Submerge the green beans in water and add the cinnamon sticks. Close the lid and let it sit for three to five days.

During this time, the beans will absorb the cinnamon-infused water, giving it those tasting notes. Remove the coffee once ready, and let it dry to 11% moisture. You can use dehumidifiers or even your roaster (set to 35°C) and allow the coffee to dry out slowly.

On the farm, the process is slightly different. Last year, I saw some coffees from Colombia exported by Coffeenet with this cinnamon profile. The lots were dry fermented in an aerobic environment, with tartaric acid and cinnamon sticks.

sasa pointing at coffee plantations


In 2019, I was invited to judge the La Loja competition in Ecuador. While cupping one of the tables in the first round, I smelled one particular coffee which had an intense aroma of tropical fruit.

When we tasted the coffee, this tropical flavour was completely dominant. Many judges suggested checking to see if the green beans could produce this flavour. We ran some tests, and afterwards chose to disqualify it from the competition, as it was clearly infused.

The following day I spoke to the producer. He said that he had used the CM process, but also added local tropical fruit flavouring during and after fermentation. He gave me some fruit to taste, and it was delicious. It tasted exactly like the coffee.

However, this coffee was then used to win the Italian Brewer’s Cup a few weeks later. The competitor using it was not aware that it was infused.

Some time later, I was contacted by the Cup of Excellence on several different occasions about a similarly strong and unusual-tasting coffee from Colombia. When I tasted it, I was surprised by the distinctive smell of rose water and red fruit.

The producer explained that he anaerobically fermented the cherry for 48 hours at 18°C. He then depulped it and began a second stage of anaerobic fermentation in mucilage for 96 hours at 18°C.

After that, he explained that he performed a “thermal shock” on the coffee. He talked me through the process: washing the parchment with 40°C water and then again with 12°C water, before leaving it to dry.

I felt that this didn’t make sense. After conducting hundreds of experiments with a farm in the same region of Colombia, I thought that this kind of intense taste was unachievable through fermentation alone.

Of course, I didn’t want to rely on just my opinion. To confirm it, we arranged for the coffee to be sent to Europe to be tested. We got results that this coffee had been infused with essential oils.

coffee cherries ripening


While there’s no issues for the general consumer, the rules for the World Coffee Championships state a competitor may not use a coffee which has had any additives, flavours, colourants, perfumes, or aromatic substances added between harvest and extraction.

Competitors need to obtain this information from the farmers and verify it to ensure they aren’t disqualified. The two I spoke to in Amsterdam and Boston were confident that their lots were 100% non-infused.

However, I believe there’s no way they could have had such a strong cinnamon profile without it. Cinnamon and rose notes can appear in coffee, but at such an intensity, it is highly unlikely that these flavours were natural.

In recent years, we have also seen a trend of unusually-flavoured coffees winning at some prestigious competitions, such as the Cup of Excellence and national Brewer’s Cup and barista competitions.

This has made me wonder what will happen with coffee competitions in the future. What if we see more competitors using these infused coffees? How will this affect our industry?

The issue isn’t that these coffees are being produced. I have no issue with using essential oils or cinnamon sticks to infuse or flavour coffees. In many markets around the world, coffees like these will be popular. The problem is transparency.

At the time of writing, championship competitors can still buy these coffees under the impression that they are experimentally fermented lots. In reality, they are infused. This then leads to the producer becoming less trusted, and can even mean the competitor is automatically disqualified.

On the other hand, transparency is improving with infused coffees in some areas. The cinnamon coffees I cupped from Coffeenet last year were delicious, and the company informed me beforehand that they were infused with cinnamon.

How do you check if your coffee is infused?

There are a few different ways to check for evidence of artificial infusion in coffee.

The best and most accurate way is to send your coffee to a lab for testing through methods such as gas chromatography. However, this is costly and not accessible for everyone.

Cupping it may give you some idea, but if you’re inexperienced, this too may not be sufficient. I put together a few steps which pretty much anyone can walk through to check if green coffee has been artificially infused:

  • Grind green coffee to a very coarse grind size.
  • Place 20g of the ground green coffee in a cupping bowl. Pour 40°C water onto it, and let it sit for about 10 to 15 minutes.
  • Taste it. If you can taste strong jasmine, rose, or cinnamon notes even from the green coffee, that is strong evidence it’s been infused – as non-infused coffees shouldn’t have these flavours until after they’ve been roasted.
  • You can then roast the coffee, and cup it alongside the green coffee. If you can taste the same flavours and less of the coffee’s natural characteristics, this is even stronger evidence that it has been infused.
  • Finally, you can leave roasted coffee (if you suspect it has been infused) in dry storage for upwards of six months. If you then cup it, rather than tasting dull or stale, it will still taste of the infused flavour.
coffee farmers in honduras

One of my biggest concerns is that farmers who are growing their coffee in extreme conditions and cultivating rare and expensive varieties could miss out in the future because of these infused coffees. At the same time, there are brewers and baristas who understand how to perfectly extract an espresso shot, but lose out to infused coffees that score perfectly in aroma and flavour.

Since I competed in 2015, farmers around the world have innovated with processing. But without transparency, I believe that the next generation will fail to be inspired by what we are doing today. At the time of writing, it is still challenging for judges to easily conclude whether or not a coffee is infused. This could be a major challenge in the future.

Ultimately, we need to remember next generation of the coffee industry will be watching the champions and ambassadors of today. We have an obligation to inform, educate, and inspire them, and to leave them with the tools to improve our industry across the board. This is why we need to raise awareness and begin discussing these infused coffees.

Photo credits: Lavazza, LDC, Martina Bozzola

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