Genetics, Terroir, or Fermentation?
Single-origin cacao is sold on place. The bag names a country, often a region, sometimes a valley, and the implication is that the flavour in the cup comes from the ground it grew in.
Place does matter. But three things determine what a cacao tastes like, and place is not the largest of them. Comparing the three honestly is more useful than the marketing, and it changes what you should look for when buying.
Three levers, and they are not equal
Flavour in cacao is produced by genetics (which variety), environment (where and how it grew), and post-harvest processing (what happened in the days after the pod was cut).
Most people assume that ranking. The working consensus among people who study cacao flavour runs closer to the reverse — processing first, genetics second, environment third. Not because place is irrelevant, but because the other two are capable of overwhelming it entirely.
Lever one: genetics
Cacao is more genetically diverse than the old three-way split into Criollo, Forastero and Trinitario suggested. Genetic work published in 2008 reorganised the species into ten groups based on actual population structure, most of them clustered in the upper Amazon where cacao originated.
That diversity has been narrowing. CCN-51, developed in Ecuador in the 1960s for yield and disease resistance, now accounts for an enormous share of world production. It is a capable plant and it is not what most heirloom varieties taste like.
Chuncho, the variety Pacha Mana works with, belongs to the Alto Amazonas grouping and grows in the eastern highlands of southern Peru near Quillabamba. Its beans are small, its pods fewer — the farms it comes from produce roughly 30 to 40 percent less volume than they would with a hybrid, which is the entire reason it keeps being replaced elsewhere.
How much does genetics move the cup? A great deal, and it sets the ceiling. A variety without complex flavour precursors cannot be processed into complexity. But genetics establishes potential rather than outcome — a superb variety, badly fermented, tastes worse than a mediocre one handled well.
Lever two: terroir
Cacao grows within roughly twenty degrees of the equator, generally below a thousand metres. Within that band, several environmental variables plausibly affect flavour.
Elevation brings cooler nights and slower pod maturation, which is broadly associated with more acidity and aromatic complexity — the same argument made for coffee, where the evidence is stronger.
Shade. Cacao evolved as an understorey tree. Grown in agroforestry under taller canopy, as Chuncho is, it grows more slowly and yields less, and the usual claim is that this concentrates flavour. Shade also demonstrably affects soil, moisture retention, and pest pressure.
Rainfall and dry season set flowering and harvest timing, and a distinct dry period matters for drying conditions after harvest.
Soil affects nutrition and, as below, mineral uptake.
How much does terroir move the cup? Honestly: less than the language around it implies. The effects are real but subtle, and they are readily swamped by a poor ferment. Much of what gets attributed to a valley is attributable to the fermentary that valley happens to contain — often a well-run one, because regions with reputations tend to have invested in post-harvest infrastructure.
Lever three: post-harvest processing
Here is the fact that settles the ranking. Unfermented cacao does not taste like chocolate at all. Not weakly — not at all. It is bitter, astringent, and flat, and no amount of roasting rescues it. Essentially every compound you recognise as chocolate is created after the pod is opened.
The sequence takes five to seven days. Beans are removed still coated in sweet white pulp and heaped in boxes or under leaves. Yeasts consume the pulp sugars, producing ethanol. Lactic acid bacteria follow. Then acetic acid bacteria convert the ethanol to acetic acid, and the mass heats — reaching somewhere around 45 to 50°C.
That combination of heat and acid penetrates the bean and kills the embryo, which breaks down the cell structure and allows enzymes to reach proteins and sugars they were previously separated from. The products are amino acids and reducing sugars: the precursors that roasting later converts into chocolate flavour.
Drying follows, typically five to ten days in the sun. Too fast and acetic acid is trapped in the bean, giving a sour cup. Too slow and mould takes hold.
How much does processing move the cup? More than the other two combined. It is also the lever most subject to human decision — how long, how often turned, at what depth, and whether anyone is paying attention on day four.
This is the argument for cacao processed at origin by the people who grow it, and it is a stronger argument than the romantic version. When beans are sold wet to an intermediary and fermented in bulk alongside other farms' beans, the variety and the valley survive but the decisions are made by someone with no stake in that specific lot. Pacha Mana's beans are processed bean-to-bar by the family that grows them, which means the largest single flavour lever stays in the hands of the people with the most reason to get it right.
The one place terroir is measurable: cadmium
There is one variable where the environment's contribution is unambiguous, quantifiable, and consequential — and it is not a flavour compound.
Cacao takes up cadmium from soil, and uptake is strongly governed by soil geochemistry and pH. This is why Latin American cacao generally carries more cadmium than West African, and why the levels vary between neighbouring valleys with different parent rock.
It matters commercially because the EU set maximum cadmium levels for cocoa products that came into force in 2019, with limits varying by product type. Farms on the wrong geology have had genuine market access problems.
Pacha Mana publishes its test results — cadmium at 0.126 ppm and lead at 0.010 ppm — and attributes the levels to high-elevation growing conditions and soil quality. Whatever the exact mechanism, this is the clearest case of place showing up as a number rather than as a tasting note, and it is the one terroir claim you can actually verify by asking for a lab report.
What this means for a single-origin label
A country name tells you comparatively little. A region narrows it. A named farm narrows it considerably more, because at that resolution you are identifying a fermentation protocol rather than a climate.
Questions that discriminate, roughly in order of usefulness: Who fermented it, and for how long? Was it processed at origin or shipped wet or raw? Which variety? What elevation? Are there lab results?
Notice that the first two are processing questions and the marketing rarely answers them. A brand that can tell you the ferment ran six days in wooden boxes turned twice daily is telling you more about the cup than one that can only name a mountain range.
A flight that tests this
You cannot isolate these variables at home the way a research station could, but you can get closer than a single cup allows.
Hold everything constant — same ratio, same water, same temperature, same vessel — and vary one thing. Our guide to running a tasting flight sets out the protocol properly; what follows is what to vary for this particular question.
To isolate genetics: compare an heirloom variety against a commodity cacao from a similar region and processing standard. The difference in aromatic complexity is usually the most dramatic comparison available.
To isolate processing: compare two cacaos of similar variety and origin from different producers. Differences here will show up as sourness, flatness, or off-notes rather than as different fruit — a sour cup usually means drying was rushed, and a flat one often means the ferment was cut short.
To isolate terroir: this is the hard one, and the honest answer is that you probably cannot at home. Isolating it requires the same variety and the same processing from two different places, which is rarely available. If someone offers you a confident tasting note about the effect of a particular hillside, that is the comparison they would need to have run.
Taste at two temperatures, around 65°C and again near 40°C. Processing faults are most obvious cool — sourness and astringency come forward as the aromatics fade, while genuine varietal complexity holds up better.
For the comparison, our pure ground Chuncho cacao is the heirloom side of the first test, and the background on the variety and the family growing it is in our pieces on Chuncho as a rare heirloom and farming it.
