Two cherries, one farm
On a cloud-wrapped farm in the hills of Matagalpa, Nicaragua, the Orange Bourbon trees don't all agree with each other. Most ripen to a clean, even orange. Some ripen striped, with pale and dark bands running from stem to tip like a tiger. Each tree picks a side and sticks to it.
When the Mierisch family separated the striped cherries at Finca La Huella, they made a different coffee from the solid orange fruit on the trees alongside. Lighter, sweeter, more delicate. There's one sack of it this year, and it's out now.
It left us with a question we couldn't put down. What is the colour of a coffee cherry actually telling you? The answer turns out to be less than the coffee industry tends to claim, and more than you might expect.
What makes a cherry red, yellow or orange
A coffee cherry's colour comes mostly from two families of pigment, with a supporting cast. Anthocyanins, the compounds behind the reds and purples of blackberries and red cabbage, give red. Carotenoids, familiar from carrots and mangoes, give yellow and orange.
In 2020, a team led by Patricia Esquivel at the University of Costa Rica measured pigments in the skins of five varieties grown at Tres Ríos. The red-fruited ones were full of anthocyanins. The orange Anaranjado had far less, and the yellow Caturra Amarillo had none at all. Lutein and beta-carotene turned up in all five.
So in Anaranjado, at least, orange is a red cherry with the red turned down: less anthocyanin sitting over the yellow-orange carotenoids underneath.
The chemistry gets busier the closer you look. In April 2026, researchers at Pu'er University in Yunnan profiled three Catimor selections with yellow, pink and purple fruit and identified 40 anthocyanins, six proanthocyanidins and 34 carotenoids between them. Proanthocyanidins turned out to matter for the yellow fruit, and different anthocyanin mixes for the red and purple.
Colour, in other words, is an outcome. Different varieties can reach a similar shade by different routes: different pigments, different genes switched on, different timing.
One thing worth being clear about. In a washed coffee, the skin and pulp come off before the parchment is dried, so whatever makes a striped cherry taste different, it isn't pigment rubbing off on the bean. The stripe could still be a clue, though. Ripening, seed development and the chemistry of the fruit around the seed are all linked.
What colour tells a picker
Pickers use colour for a reason. As a cherry ripens, its skin changes colour and its chemistry changes with it.
In 2024, researchers at Yunnan Agricultural University followed coffee fruit from green through green-yellow, red and red-purple, tracking the pigments and the genes behind them. Carotenoids fell steadily as the fruit matured and anthocyanins climbed, with the green-yellow stage as the turning point.
What's inside changes too. A 2023 study from the same university tracked sugars, organic acids and amino acids, the raw material for flavour in the roaster, across four stages of ripeness. Fructose and sucrose rose steadily as the cherries matured. And when Sebastián Velásquez and colleagues roasted and cupped coffee from seven stages, from fully green to overripe purple, the unripe cherries scored clearly lower. Everything from partly ripe to overripe showed few differences in the cup.
So colour tells a picker a lot about ripeness, and tells a roaster surprisingly little about the cup once the fruit is past green. Between varieties, even “red means ripe” falls over: a ripe Yellow Bourbon, Orange Bourbon or Pink Bourbon is meant to look different from a ripe Red Bourbon.
The genetics behind yellow and orange Bourbon
By 1942, Carlos Arnaldo Krug and his colleagues at the Instituto Agronômico (IAC) in Campinas, Brazil, had shown that yellow fruit was controlled by a single genetic factor. They called it xanthocarpa, from the Greek for yellow fruit, or xc for short.
Every plant carries two copies. Two red copies (XcXc) give red fruit. Two yellow copies (xcxc) give yellow. One of each (Xcxc) sits in between, but closer to red than you might think. When Alcides Carvalho and colleagues at the IAC grew out 30 Yellow Bourbon progenies across five sites, 82 of the 2,930 plants turned out to be Xcxc, the result of natural cross-pollination in the plot where the seed was collected. Their fruit was light red.
That has a practical consequence. A plant with one of each won't breed true. Arabica mostly pollinates itself, so plant its seed and you'd expect roughly one red to two light red to one yellow, plus whatever pollen the neighbouring trees add.
The same study is careful about where Yellow Bourbon came from. It probably arose near Pederneiras in São Paulo state, either as a mutation of Red Bourbon or from a natural cross between Red Bourbon and Amarelo de Botucatu, a yellow-fruited Typica. The authors left both doors open.
Orange Bourbon is usually described in the trade as a natural colour mutation of Red Bourbon, and it's strongly associated with El Salvador. The genetic literature here is much thinner. If the IAC's heterozygotes came out light red, the xanthocarpa factor on its own doesn't obviously account for a properly orange cherry. It could be a different version of the same factor, or a different gene entirely. We haven't found a published study that settles it. For now, Orange Bourbon's colour is a description, and its genetic explanation is an open question.
When colour sends you the wrong way
If colour were a reliable guide to ancestry, naming coffees would be easy. It isn't, and Colombia has supplied two very good cautionary tales.
Pink Bourbon turned up in Colombia among Bourbon trees, and its pink fruit looked like a Bourbon colour mutation, or a cross between Bourbon types. Importer Cafe Imports has written up two rounds of genetic testing. In 2017, two plants came back closest to wild Ethiopian coffee. In 2023, Christophe Montagnon of RD2 Vision was blunter: Pink Bourbon “has nothing to do with Bourbon, as it is an Ethiopian landrace.” Of the five samples tested that year, only one was pure Pink Bourbon. The rest were mixed with Bourbon or Catimor, a reminder that a lot sold under one varietal name can still hold more than one plant.
Bourbon Ají took a different route to the same place. José Herman Salazar noticed trees on his farm, La Guaca in Pitalito, Huila, whose cherries smelled of sweet red pepper at harvest. He picked them separately and entered the lot in the 2021 Colombia Cup of Excellence, where it placed sixth with 89.32 points. Questions followed. Cup of Excellence had it tested by RD2 Vision and reported an Ethiopian landrace, one missing from many of the major reference collections.
Both names are still in commercial use, though some roasters now simply call it Ají. A cherry that looks or smells different is an observation. DNA is where a conversation about ancestry starts.
What apples can teach us about stripes
As far as we can find, nobody has published a peer-reviewed study explaining stripes in coffee cherries. Apples are another matter, because stripes sell apples.
In 2011, researchers from the University of Minnesota and New Zealand's Plant & Food Research looked at Honeycrisp, where a single tree can bear both striped and evenly blushed fruit. The red stripes held more anthocyanin, driven by a regulatory gene called MYB10 working harder. Yet the gene's DNA sequence was the same in striped and blushed fruit. What the team found instead was methylation, chemical tags that turn a gene down without changing its code, sitting heavier in the paler stripes.
That's one route to a stripe: the same DNA, doing different things in different parts of the fruit.
There are other routes. One is a chimera, where genetically different cell lines grow side by side in the same plant and show up as sectors or stripes. Another is transposable elements, the “jumping genes” Barbara McClintock found in speckled maize, which can switch a pigment gene on in some cells and off in others.
Any of these could, in principle, produce a striped coffee cherry, and they'd have very different consequences. A stable inherited mutation behaves differently from a tissue-level chimera or a reversible epigenetic switch. Looking at the stripe won't tell you which one you've got.
Apple growers have another useful word: sport. A single branch suddenly bears fruit of a different colour, and growers graft it and propagate it. Coffee has its own selected mutations and clonal material, but most Arabica is still grown from seed, which is partly why a trait like striping can hide in plain sight.
Striped cherries in coffee today
Striped cherries aren't unique to La Huella. Separated lots are now sold from several farms in Colombia, including in Huila and Cauca, usually as Red Striped Bourbon or simply Striped Bourbon: red cherries carrying orange bands.
There's very little published science behind the name. We've found plenty of commercial evidence that Striped Bourbon exists as a recognisable type in the field, and no peer-reviewed genetic study or published lab report on its ancestry. Some sellers list it as another name for Ají. We'd keep them apart until someone shows otherwise: Ají was picked out by its smell and has been tested, and Striped Bourbon was picked out by its stripes and hasn't.
That leaves a question worth asking. Is Striped Bourbon a Bourbon mutation, a different lineage that happens to look like Bourbon, or something happening in how the plant switches its pigment genes on and off?
Finca San José in El Salvador adds another piece. We've bought an Amarangia lot from them before, listed as Yellow and Orange Bourbon, and Luis Rodriguez, who helps run the farm, tells us the orange fraction there is entirely striped. On other farms, Orange Bourbon comes up solid orange.
What sets La Huella apart is having both forms on the same land, in broadly the same conditions, through the same mill and the same washed process. That's about as close to a controlled comparison as a working farm will give you, and a far better one than putting a striped coffee from Colombia next to an orange one from El Salvador and trying to explain the difference from the cup alone.
What we can say, and what we can't
We've cupped both fractions from La Huella. The solid orange cherries make a lovely Bourbon, a touch fuller in the body than the farm's others. The striped cherries make something else entirely: lighter, more delicate, with a sweetness that lands somewhere between strawberry fondant chocolates and Turkish delight.
Same farm. Same mill. Same washed process at Beneficio Don Esteban. Different cups.
We can't tell you why. It could be genetic. It could be a change in how the plant regulates its pigments, a chimera or something else at the level of the plant. It could be linked to how the fruit ripens. It could even be partly down to where on the farm those trees happen to sit. We haven't had the material genetically tested, and we won't call it a new varietal on the strength of how it looks. After everything above, that would be a bit rich.
What we can tell you is that this coffee exists because Wingo Mierisch looked closely at his trees and asked his pickers to do something awkward, and because our Green Buyer Roland spent a year reminding him to do it again. The result is a single sack. If you want to taste what a stripe can do, now's the time. Check out our Striped Orange Bourbon lot from La Huella here →
How we'd actually test the stripe
The plan is simple. Doing it properly isn't. We'd want several striped trees and several solid orange trees, samples from more than one harvest, and cherries matched as closely as possible for ripeness. The lots would go through the same washed process, with the cupping done blind and repeated.
Alongside that, leaves from each tree could be genetically profiled, including the xc colour gene and a much broader set of markers. The skins could be analysed for anthocyanins, carotenoids and everything else, and the fruit around the seed compared at matching stages of ripeness.
That would start to separate three things that are easy to confuse: what the plant is, what the fruit is doing, and what ends up in the cup.
Next year we may buy both fractions and put them side by side properly. If we do, you'll read about it here.
Further reading
If you want to dig further, these are the five sources we'd start with.
- Pink…Bourbon?: Cryptozoology and Genetics in Specialty Coffee, Cafe Imports (2023). The full story of Pink Bourbon's two rounds of DNA testing, and the clearest explanation we've found of how varietal identification actually works.
- The Fascinating History and Renewal of Brazil's Yellow Bourbon, Daily Coffee News (2019). How a yellow cherry near Pederneiras became one of Brazil's defining coffees, with Krug's work on the xanthocarpa factor along the way.
- Coffee (Coffea arabica L.) By-products as a Source of Carotenoids and Phenolic Compounds: Evaluation of Varieties With Different Peel Color, Esquivel et al., Frontiers in Sustainable Food Systems (2020). The Costa Rican study behind our red, orange and yellow comparison. Free to read, and more approachable than the title suggests.
- Apple skin patterning is associated with differential expression of MYB10, Telias et al., BMC Plant Biology (2011). The Honeycrisp stripe study. Free to read, and a neat demonstration of the same DNA painting two different apples.
- Volatile and sensory characterization of roast coffees: Effects of cherry maturity, Velásquez et al., Food Chemistry (2019). Seven stages of ripeness, roasted and cupped. The abstract is free; the full paper sits behind a paywall.