123 comments

[ 1.8 ms ] story [ 188 ms ] thread
Brassica oleracea would have a word there.
I wonder if the cultivars of brassica oleracea have greater genetic variation.
(comment deleted)
Terroir. That’s it, that’s the post.
Was my first idea upon reading the article. I remember being surprised when I was abroad and asked about nice looking tree, and it turned out to be a Rhododendron, which only grows as a medium sized bush in my country. Climate and soil make a huge difference, even at ±1500km. Coffee is grown all over the world.
You can buy different fertilizer for rhododendron to change the color.
IIRC they change colour depending on how acidic or alkaline the soil is!
No, that’s not the post.

> ” they seem to be mainly the result of wholesale swapping, deletion and rearrangement of chromosomes.”

The article is fairly informative about the genetics of coffee, btw. Well worth reading.

Did we read the same article?

I saw no mentions of volatile aromatics(aka the flavor and aroma compounds) and how they isolated them in different strains. I saw no mention of what genetic markers are tied to specific flavor profiles.

I did see a lot about disease and pest resistance. My glib comment is how the title seems to have fuckall to do with flavor (which, again, is affected predominantly by the terroir, or more specifically the mineral/chemical uptake of plants in a similar region) as the article is just run of the mill “people in a commercial industry and doing science to understand their product, isn’t that neat?” content.

All coffee and all wine tastes the same to me, can people really tell the difference or is it mostly an upper class pantomime?
Have you compared single origin coffees from wildly different regions of the world?
Of course not, but I often have colleagues qualify some coffee as "excellent" and some other as "terrible" and I cannot ever tell the two apart.
btw, I don't think the poster above is being snarky. There are many coffee shops that will serve two distinct single origin brews and you can just compare by ordering one of each.
I was indeed not being snarky. There are plenty of outlier examples but if someone set in front of me an arbitrary coffee from Costa Rica, Ethiopia, and Sumatra I'd usually be able to tell you which was which.
They really do taste different. Try a French roast vs a light roast some time if you want an extreme example, or a very tart wine and a very sweet one. The outliers at each end of the spectrum are very different.

If you can't tell which is which in those cases then you might legitimately have a problem with your sense of taste.

Roasting certainly changes the flavor of coffee, but can you really tell the difference from coffee bean X and coffee bean Y roasted the same way?
Yes, although roasting them exactly the same way is probably not a great idea. But you can roast them to a similar level.

It can be quite a subtle difference, and part of the flavor might also come from the way they process the coffee before it gets roasted (washing the beans, letting them sit in the fruit a little longer, etc.)

But I am sure many people can taste the difference between a costa rican and an ethiopian coffee, as long as it's not roasted to charcoal level. That might influence why people ask this question. A lot of coffee people drink is roasted so dark that there's probably no big difference anymore. Additionally it's often blended. I guess it's how you guarantee a consistent flavor (and bottom line).

I do think I can tell between robusta and arabica. I am not sure about two arabica. Probably not.
I can. I recently roasted up two batches of beans -- some El Salvadoran and some Costa Rican. I roasted both to a Full City (dark) roast level. They were very different. I finished the Costa Rican quickly. It was delicious. I'm struggling to finish the El Salvadoran. I'm terrible at describing flavors, but I'd say it's sour with a tea-like flavor.

There's a lot that goes into the flavor of coffee. The beans themselves of course. Brewing technique has a big influence as well. But also growing conditions (altitude, soil composition, rain/sun mix, etc.), processing (wet vs dry process, fermentation time, etc.), handling and shipping (dry or moist conditions), and probably more I don't know about.

I strongly prefer wet-processed beans (mostly south American varieties) over dry-processed beans (mostly African varieties are processed this way). I haven't tried honey-processed yet.

Green beans stay "fresh" for a really long time, but once roasted beans become stale quickly. I can taste the difference between my roasts a day or two after roasting vs days or weeks later.

I've often wondered how fermentation effects bean flavor. It was a surprise for me to learn recently that coffee beans were fermented in the first place!
Yes, single origin beans from different countries taste different. Colombia is really sharp. Kenyan is more complex. Honduras has a good balance. Ethiopian has a couple of sub-varieties that taste very different from each other. Overall, Ethiopia still makes the best coffee in the world.
With some, yes. The really obvious ones are fruity vs the more aromatic spice flavours. I can't tell regions apart and I'm unlikely to pick up which specific fruity flavour a coffee is meant to have - stonefruit vs berry or whatever.

The biggest problem I have when trying to run blind taste tests is that different beans behave so differently that it's hard for me, with my low level of skill, to prepare them the same way. I can pack a basket exactly the same with a coffee of roughly the same roast put through the exact same grinder setting and then extract them for the same length of time, but one coffee will consistently come out underextracted for some unknown bean-related reason. In that case you'd just pick up the difference in preparation rather than the flavour of the beans themselves.

Yes, absolutely. The other thing to note is that you cannot roast two different beans “the same way”. They do not roast the same. You could roast two to the same degree (same final temperature, or final color), but the way that two wildly different beans absorb heat is going to be radically different. Density of the bean and the internal moisture play a huge role in this. Denser, more moist beans will roast slower and require more heat. Likewise, less dense beans will roast more quickly and may be subject to defects relating to essentially scorching if the same amount of heat is applied.

I roast coffee at a… semi professional level, and I would say that roasting can only make a coffee worse, it cannot be additive. You only bring out the flavors of the origin beans, and if you do it wrong they will taste bad. You can’t make certain coffee taste like fruit, for instance. It just doesn’t exist in the origin coffee.

I am currently drinking three different coffees, and they have three wildly different flavors. One has a very low body, tea like, and earthy flavors. One has a chocolatey cocoa flavor, and one tastes like syrupy rich body with ripe cherry. It’s absolutely unmistakable.

Then you should widen your search.

I buy a coffee advent calendar every year. Beans from small roasters, different sorts of processing, and so on. I've had coffee that tastes more akin to a fruity tea than coffee - and some that tastes much more like the coffee flavor I expect. Some of them were surprising - I didn't know coffee could taste like that.

A lot of coffee in your average stores taste somewhat similar - some much more than others - but are certainly not the same. If they didn't, folks wouldn't really have as many preferences. Roasts make a difference as do the beans origin and quality.

I don’t know about wine, but coffee do tastes different. Very different.

Compare a pour over at home with a cheap supermarket brand and a espresso at a fancy coffee shop. You can say they all deliver the same “pleasure” to you and it they are interchangeably experiences, but probably they effectively taste different. Unless you have a problem with your tasting sense.

> Unless you have a problem with your tasting sense.

I mean, there's two comments proposing that already, but why would that be the case only for high-ceremony drinks (coffee, wine...).

Have you done that test? You really see no difference between two very different beans using different preparation methods?

To your question. I think that’s where the economic incentives for creating and selling different variations are.

Tea also, but tea gets it from different plants.

I can taste differences in hot chocolates, btw, solid bar chocolates too. Hershey’s milk chocolate bars in the US are horrible to my taste. Any brand milk chocolate bar where I live (Brazil), tastes much better. Even the supermarket cheap ones. But more fancy chocolate bars do taste different.

In my case, a cheap chocolate bar (that is not US Hersheys) is good enough for me, so I don’t care about the fancier ones. But they do taste different.

Edit: I do believe there are marketing and status incentives to make a big deal about the difference in this high-end stuff and there is a game of “pantomime” in place as you say. Definitely is there. It just isn’t a 100% “emperor has no clothes” situation.

That’s the scenario for “high-end bottled water” in my opinion. They all taste the same and is 100% marketing

Have you tried high end bottled water and compared?

I couldn't care less for the regular brands, but usually really enjoy higher end mineral water.

Cheap bottled wate has an odd after taste and high end ones taste like normal tap water. No hint of tropical forest or alpine ice at least for me.
Tap water tastes like chemicals to me, I have to at least let it stand in a bottle and rest for a few hours to be able to drink it.
I tried in fancy restaurants. Never noticed a difference.
Can you tell the difference between different types of chocolate?
I'm no connoisseur at all, but I can tell the difference between a Shiraz (fruitier) and a Cab Sav (drier). Mainly because they're the ones I've had more experience with.

Couldn't tell you a Grenache versus Merlot because I haven't reached whatever baseline of recognition is required.

That's been a very slow 20 year journey. I'm not detecting hints of blueberry or oak, that feels like pantomime still.

> I'm no connoisseur at all...

Then proceeds to speak in completely alien language, thank you for proving my point :)

I am saying learning such language takes years of practice, and such a hobby is only available to (relatively) few.

(comment deleted)
Ripe Australian Shiraz (14+% alcohol) has really distinct blueberry, it was a style heavily favoured by Robert Parker and really common in the early 2000s, but it's tapering off now. Syrah, the same grape, from northern Rhone is cooler climate, lower alcohol and has more of a pepper profile.

Grenache - I tyically drink Spanish Garnacha - has a crunchy berry profile in a young early drinking wine, but can get more interesting in pricier examples from Priorat etc.

Grenache + Syrah (aka Shiraz) + Mourvèdre (GSM) is the southern Rhone blend, and is typically very high alcohol and quite opulent. I'm not much of a fan though.

Mourvedre is fantastic stuff when done well. Mourvedre reminds me of Carignan, both make savoury / meaty wines. Domaine Tempier Bandol is a Mourvèdre-dominant blend and is absolutely delicious, my favourite example of it.

Oak is a big part of really good wine. American oak, French oak and unoaked all produce very different wines. Typical Rioja has heavy American oak flavours, while e.g. red Burgundy typically has pronounced French oak.

I love the "underwater part of the iceberg" of life that's implied by that level of knowledge summarised "above the water".

There is a very limited number of things an individual can get deeply into.

(comment deleted)
IMO the best way to start noticing differences is tasting two cups together. then you really notice the contrast, it's harder to remember what the last Sumatra tasted like.
Different non-fortified, non-dessert still red wines using different grapes taste about as different as raspberry, cherry, blackcurrant (cassis) and blackberry juices taste from each other. They're all recognizably wine, but the fruit flavours, tannin, acidity, sweetness, oak and mouthfeel varies quite a bit.

Cheap house wine from an open bottle at a bar or restaurant without a wine list can taste pretty similar between bottles. These wines are typically industrial product made in large vats where the wine itself, excluding taxes and everything else, costs a fraction of a dollar. If the bottle has been open for a day, the wine loses most fruit flavours, and structurally cheap wine is pretty similar - not very tannic (it's not usually a crowd pleaser), probably has added sugar.

> taste about as different as raspberry, cherry, blackcurrant (cassis) and blackberry juices

I can trivially tell these apart, and I did not have to "study" any of that.

From other comments it sounds like doing the same for wine takes years of practice, which is obviously only accessible to the leisure class.

No - I could put a glass of Burgundy, an oaky Rioja and ripe Australian Syrah in front of you and you'd be able to trivially tell them apart, no training needed.
Of course. But now do a blind taste with someone off the streets, and ask which one is the "oaky Rioja".
That’s a different statement from “they all taste the same.”
Do a blind taste test of the fruits and ask the same question. The answers may surprise you - humans are shockingly bad at blind identification of common foods.
Dark roasted coffee will usually remove most of the differences that were in the original beans. To notice the details you will have to use light to medium roasted beans and be reasonably good at preparing the coffee well. There are many parameters you can adjust while brewing coffee (not all methods expose those parameters), and this can affect the taste rather significantly.
A lot of the taste of coffee comes down to process, from roasting to preparation and includes things like temperature, pressure, and time. And it does taste different.

Some of it is just undrinkable and makes me gag; horrible stuff and other coffee is enjoyable to drink.

That said coffee afficionades do go overboard with their fussiness. A good coffee is good coffee.

I bet you could tell the difference if you lined up multiple samples and tasted in succession. I think it's a perfect pitch thing, some people seem able to identify taste without reference like some people are able to identify tone.
I work as a software developer but once trained as a barista when considering opening my own coffee shop. I can offer some fact-based reasoning as to how different coffees have the capacity to taste different (whether people have the capacity to discern the difference is another matter).

The dominant factors in the flavour of coffee comes from the preparation, both the roasting and the brewing.

Roasting reduces the acidity of the beans and draws out oils towards the outer surface. Both the acidity and oil content of the affect the flavour, with the acidity directly impacting bitterness and the oil impacting the smoothness.

The amount of total acidity contributors and oil contributors that are drawn out of the bean when brewing are a direct function of water temperature, water pressure and duration. Too low a temperature and the resulting drink is more akin to watery coffee dust. Too low a pressure and you get sort of the same results.

An ideal temperature and pressure combination, given a fixed duration (let's say 30 seconds) draws out enough of the oils to balance the acidity to get a good strength coffee (optimal bean to drink yield) that doesn't taste horrid. The acidity takes longer to draw out such that too long a duration results in a more bitter (and generally less acceptable) flavour.

That's a rough overview meant only to highlight that it certainly is possible, from both roasting and brewing, to significantly alter the flavour of coffee. I've oversimplified for brevity.

But can differently-grown beans of the same type affect flavour?

I don't grow coffee beans but I do grow tomatoes. From personal experience, the length of growing season, the amount of sunlight and the average temperature across the growing season affect the quality of the fruit. I find the same for sweetcorn, squash and many plants that grow above ground.

I don't think it is a stretch to suggest that the same factors have the capacity to impact the oil content of coffee beans if nothing else.

If growth conditions impact the oil content of the beans and the oil content of the resulting drink impacts the flavour, it seems plausible to suggest that the growth conditions can impact the flavour.

This matters a great deal as the coffee crops are under threat from climate change and if they are to survive at scale will need broad domestication. Large scale effort is going into it as it is a very important cash crop.

Understanding where they get their flavor and how to replicate it can only lead to better success in this effort.

As Asia is increasingly becoming caffeine addicted we can expect these crops becoming a real disaster very quickly. Palm oil will be nothing compared to this.
> we can expect these crops becoming a real disaster very quickly.

Can you elaborate why?

My guess would be that they expect massive and irresponsible conversion of wild areas into farmland.
It’s complex. Demand is outstripping supply in something economists like to call The Coffee Paradox which actually has a book on the subject by the same name:

https://www.amazon.com/Coffee-Paradox-Markets-Commodity-Deve....

More information on the short term and long term issues here:

https://financialpost.com/financial-times/peak-coffee-global...

https://m.economictimes.com/small-biz/trade/exports/insights...

But the most pressing issues long term are best summarized by this article which if you read nothing else is probably the best answer to your question:

https://econreview.berkeley.edu/a-world-without-coffee-the-s...

To boot, coffee is a monoculture and deeply vulnerable like bananas.

Many plants produce caffeine besides coffea arabica and coffea robusta: yerba mate, guarana, tea plant, kola nut, et cetera. We can resort to other plants to fuel our caffeine addiction.
I think primary caffeine delivery mechanism of Asia will remain tea for a long long time and it already produces most of it.
Asia is discovering coffee. There are 6500+ of Starbucks stores in China. They sell tea too, but it is a sign.
Generally, an organism's phenotypes (observable characteristics) are a combination of its genes and its environment.

It's a bit like saying "These twins are genetically identical despite growing up at different altitudes, so how can their skin tone be so different?"

Exactly, I find the conclusion in the subheading weird.

> Flavour variations are mainly the result of changes at the chromosome level, sequencing effort finds.

Though from my limited understanding of coffee tasting, environment is one of the biggest factors in taste. Especially the altitude changes the way to plant grows and develops toxins.

> Even if a single-origin Colombian coffee bean harvest was roasted and ground in the same way as a batch from Ethiopia, a coffee connoisseur would be able to tell the difference.

But Colombia especially is known for its variety in environments for coffee harvest.

So regardless of finding genetic differences between variants, I am not sure they can draw the conclusion that this is what creates variety in flavor. They don't make the claim that a coffee connoisseur could taste the differences of two different coffee variants grown in the same environment.

I wonder how much of it is simply fake/psychological like wine tasting.
It's not fake. That said, I'm not sure what all makes a difference. For example, I'm not sure how much altitude affects things. Bean size definitely seems to. Same goes for the process (wet, honey, natural, etc). And, of course, the roast makes a huge difference.

There are some roasters out there who offer kits where you can get the same wash, same roast in different origins so you can compare and there is definitely a difference. I've had some that were extremely fruity, almost cherry tasting and others that were much more earthy/tobacco tasting. I like more fruity coffees and I find that these tend be more common in beans from Africa.

Coffee brewed a few degrees of temperature apart tastes fairly different to me. I get annoyed by people who say the difference in taste must be in your imagination. It's like color blind people saying you must be imagining the difference in red and green colors.
It's not your imagination, it's science (although it does depend on the other variables). The temperature of water changes the extraction of dissolved and undissolved solids from the bean into the water, and water changes whether oils, esters, acids, etc are folded or not, which is what we perceive as flavor (aroma combined with the 6 tastes). It's unlikely that only a few degrees would be perceptible by most people, but for supertasters, with the right coffee, it's possible.
> I get annoyed by people who say the difference in taste must be in your imagination.

I have a friend who is a supertaster, and I'm probably whatever is the opposite of that, due to lifelong allergies. We amaze each other sometimes when we eat together.

The thing is, it's normal to be annoyed by people who are challenging your reality. Most people who never learn anything that goes beyond surface level truths accessible at a broad social level are.

It is the job of intellectuals to not be mad, but rather revel in challenges to their reality.

This is the difference between someone who develops a robust worldview and someone who develops a comfortable worldview. I have my doubts that you can switch between these two modalities of learning.

FYI I drink elaborately roasted and brewed coffee in many blends constantly. I'm open to the idea that I've been engaging in Kabuki because I f***g love science.

Are you sure?

Sure enough to feel that you can bypass cognitive bias and make an accurate assessment?

Am I sure I can taste the difference between beans of different origins? Absolutely. I'm confident you can too.
I’ve loved the concept of terrior since first hearing it:

https://en.m.wikipedia.org/wiki/Terroir

Seems to not only explain crops and tastes but also more abstractly people, and the differences in outcomes by zip codes, for instance. You are where you grow.

The concept of terroir needs to be introduced to the produce aisle of the grocery store.

Easy shortcut to explaining why our fruits and veggies have no taste or nutrition anymore.

We destroyed any natural terroir through tilling, fertilizer and pest control

This is part of it. The other part is that we demand produce year round which means transportation and long term storage. This is why tomatoes all taste meh now. As to nutrition, I’d recommend switching to frozen as it looses less value in transportation.
Funny as people use to always feel frozen was not as “healthy” as fresh
As long as we insist on being able to buy cheap fruits and veggies year round with no regards to what is or isn't in season, we have no one but ourselves to blame.
Organic seems to sell well, but often just as tasteless. I bet the market would recognize something like a terroir label which designate the value of taste. The price of apples for instance seems to reflect this already, the pricier ones do taste better. The taste of apples also seems pretty resilient to long cold storage.
The downside of organic is that it might be even more energy- and resource-intensive than the alternative, and generally has no guarantee of being more nutritious or tasting better.

I remember reading years ago that organic peanuts at industrial scale can basically only be grown in arid regions, because the only effective alternative to fungicide is dry weather. That means organic peanuts are actually really bad for the environment, and due to the way water is priced in the US, the price on the shelf does not reflect its true cost.

Likewise for organic blueberries and cherries shipped up from Peru and Chile in January. It's hard to comprehend how wastefully luxurious that would have seemed at a not-too-distant time in history. And odds are high that those berries are bred for bruise and rot resistance, rather than nutrient content and flavor.

I mean, we're not optimising for taste or nutrition. We're barely even optimising for cost these days.

We're optimising for length of time the produce looks good on a supermarket shelf after travelling halfway around the world in a container ship.

All other concerns get thrown under the bus.

The really insidious aspect of this, though, is that this isn't the result of some deliberate plot; supermarkets sell what people will most buy.

If enough people switch to buying tasty nutritious misshapen local in-season produce instead of the tasteless bland cheap good-looking year-round stuff, we'll see more of that.

Time and time again, though, we all vote with our wallets for beautiful insipid gratification, and so that is what we get.

Also, refrigeration and trucking across long distances. Even some of the heaviest industrial fruit/veggies might still have some semblance of terroir if eaten local to the industrial farm. Most modern grocery stores have bought into the idea of presenting the illusion of a "year-round bounty" in their produce departments and prioritize long distance shipped reliable year-round produce over local and seasonal options (leaving those to things like farmers markets and CSAs).
So, suppose you walk into your local grocer and today the carrots are from East Dursley. Last week they were from North Grimsby. How does that affect your buying decision?

There are at least 1000s of distinct terroirs that any given crop might grow in. It's far beyond most people's cognitive ability to know any significant fraction of them.

Maybe you could devise a sharding scheme, where each grocery store got carrots from 10-20 different fields in different growing belts for year-round availability. With a limited set, consumer might learn their favorites.

That's not what led to lack of taste and nutrition. It was consumer preference combined with food supply chain logistics. People wanted redder apples, and stores wanted apples that stored well, shipped well, and were cheap. So they grew, shipped and sold Red Delicious. It's not tasteless because of farming, it's just a shitty apple. The marketplace gave the consumer (and seller) what they asked for.

Other produce does now has less nutrition (due to the farming methods you mention), and they could improve the produce if that was their goal. But it's not, because people aren't demanding improved produce. They demand "Organic", because they fear unorganic, because they fear it's going to make them sick. They don't fear a lack of nutrition (or taste), so they aren't concerned with it, so they don't demand more nutritious or delicious food, so it isn't made that way.

Americans have been programmed since the 1950s to prefer convenience, salt, sugar, and fat, over quality. Go to France, see how they eat, what produce they have. It's not because their farms are different. Their consumers just want good quality, local, seasonal food. So they get it.

I had 'swamp carrots' for lack of a better word a few months ago at an amazing restaurant in Berlin. Fundamentally different than a regular carrot - super smooth but crisp flesh, almost creamy.
A Waitrose supermarket in the UK I used to go to had a dozen varieties of apples, and also tomatoes, also noting their varietal and origin country. It was a real pleasure discovering different flavor profiles and developing favorites.

Putting aside that American supermarket tomatoes are fatally flawed (they are full of flavorless water and have a mealy texture), it's amazing to me how behind even expensive grocery stores are.

Don't even get me started on the cider...

Here's another tangent. Americans have less conceptual agreement with terroir, which is why beer and even wine now have strange names and labels. I'm being flippant but: "Total Death Winery" with a skull and crossbones logo, or 'Whisper' and other random names like this instead of a town and last name or producer.

And it's funny that French and Spanish wine labels (and I'm sure others) selling to the American market started to pull the same label marketing technique. Make it artistic, ironic/funny and memorable.

I'm old school so I don't appreciate it. But there's definitely a cultural difference. Perhaps because the US does not have a long history. In contrast, apples and wine have been a French speciality for literally thousands of years.

I think you have to buy organic produce in the US to match the quality of the non-organic produce in Europe. Whole Foods is the largest retailer of organic produce in the US.
tbh the english wikipedia article seems to lend "terroir" a meaning that it doesn't have in french: it's not really used to "describe the environmental factors that affect a crop's phenotype".

It refers to a region and the practices/traditions of the people living there, particularly for agricultural products. It doesn't have much deeper meaning than "traditional production of Devon" (or whatever other place): it _implies_ that the environment is important but it's not really what it _means_.

Sounds like "terrain" or one of the lesser used definitions of the word "territory". I think "terra" means land in Latin.
differences in outcomes by zip codes, for instance.

I feel it is important to point out that when talking about people, this less because of the physical properties of the land (proximity to superfund sites not withstanding), and more because of human controlled elements, like policy choices.

Have you looked at the research into environmental noise and brain development?
(comment deleted)
Terroir was invented by feudal landlord wine makers to justify their price fixing schemes. It has little basis in science besides the fact that plants require certain inputs.

In the coffee world the term has the effect of disempowering producers by making it seem like their labor to increase quality is futile or not valuable; that at the end it was the soil not their hard work. Places with a reputation for low quality coffee can in fact grow excellent coffee that deserves high prices. And of course you can also get bad coffee from regions with a good reputation.

The term "provenance" is preferred by some folks instead.

I've been wondering about this for a long time. Does the same grape grown under different conditions but processed identically produce different wine? Surely that's been studied before.
Absolutely. I mean, the reason different vintages taste differently is because of the climate that year. Temperature, rainfall, sunlight are all important variables. And in the case of coffee you are often relying on wild microbial communities as well, rather than cultivated inoculants.

When wine brands link soil type to flavor it is complete BS. Plant roots don't absorb minerals, they absorb the water soluble molecular components like phosphate and calcium. (Moreover those nutrients primarily come from the humus layer rather than dirt). However those nutrients can be tasted by humans even at low concentrations, hence the conflation with soil quality and using "minerality" as an ambiguous flavor descriptor.

Headline: All arabica coffee is genetically similar

But:

> The study found evidence of significant chromosomal rearrangements, especially in a varietal of C. arabica called Bourbon. There were deletions, in which fragments of chromosomes were missing — in some cases large chunks — and even instances in which entire chromosomes were absent.

Does this really count as genetically similar? I would have imagined that the presence and order of genes was an important aspect of genetic variation.

The paper itself goes into some more detail on that - the genetic diversity is found in the organization of the units among the chromosomes, while the units themselves (e.g. caffeine biosynthesis genes etc. are identical). This results in variations in gene expression levels, which alone is apparently enough to produce distinct varietals.

> "While none of the different chromosomal aberrations we have identified is introducing new sequence variants, they are all capable of altering gene dosage between homoeologs and also total gene dosage in the case of aneuploidies, deletions and duplications. These changes in gene copy number may result in expression differences and this in turn may result in significant phenotypic variation, as shown by aneuploid somaclonal variants that frequently originate from tissue culture and somatic embryogenesis. The genomic rearrangements may therefore represent an important source of genetic diversity that is continuously replenishing the very limited nucleotide diversity available within the species."

https://www.nature.com/articles/s41467-023-44449-8

I suppose the takeaway is that using functional gene sequences alone (a common approach in the pre-whole-genome sequenceing era) to determine genetic similarity misses a lot of important information.

Yeah the subtitle kinda contradicts the title:

"Flavour variations are mainly the result of changes at the chromosome level, sequencing effort finds."

Yeah, I mean technically people and coffee are genetically similar.
Not to mention ignoring Hibrido de Timor and its now popular decent Catimor.
When I was a kid, we had a pear tree growing in our yard. Yet the various foods which mom made from the pears varied greatly in taste.

With the pears, it was visually obvious to the pear-pickers (us kids) that each pear was different, and that their character varied from year to year. (I'd guess based mostly on weather.) Similarly obvious how pears that were only cooked enough to start melting the ice cream scooped onto them would taste quite different from pears cooked down into jam, or pears that were caramelized in a fry pan (to be put on top of ice cream), or...

This is IMHO, why companies like McDonalds or Budweiser are technically so impressive. A lot of people will criticize them for being crap or generic quality food and beverage products, but it takes a ridiculous amount of engineering to make a product that's consistent, at scale, all around the world. A family member used to work as an engineer at a large craft brewery and making a consistent product year-to-year was one of their biggest challenges and they didn't always get it right.
Yes, that’s impressive.

I’m not eating fast food since years now and don’t want to defend their business, but I always thought that the fast food you get at a huge chain like McDonalds is probably the most thoroughly tested you can buy.

Flower farmer here. Without reading: terroir. All coffee is grown in soil and the soil around the world is different. All plants will grow if they get the right inputs (water/light/air/macros/micros), but how they grow and the makeup of their harvestable material is going to vary by the _amounts_ and _timing_ of those inputs. I'd expect the same harvesting and roasting techniques applied to beans sourced from opposite ends of the earth would perform differently.
(comment deleted)
I’ll add on to this.

Grew up in a farming area in Central California. The variety of orange I eat from where I grew up tastes distinct the same variety grown in SoCal.

"Terroir" as typically defined is a mythical concept introduced by feudal French wine makers to justify their price fixing schemes. We're really trying to avoid importing the term into the coffee industry since it has the effect of locking producers into "their terroir" instead of acknowledging all the variables they can control (through hard work that deserves compensation) to create high quality coffee. See Lucia Solis podcast for expert commentary.

But yes, latitude, altitude, and all the other inputs make a difference (in addition to the genetic variation that does exist -- I mean no one is surprised that you can get different types of apples or organes?) But recent studies have also revealed the variations in microbial community present on coffee plants in different regions.

And besides agronomy or roasting, coffee processing can have a huge effect on flavor. Fermenting the beans -- whether in whole cherry with or without oxygen, pulped in tanks with yeast or bacteria, or all the other things producers are experimenting with these days-- fermentation is like an enormous sound equalizer board for dialing up and down various flavors.

Marketers be marketing.

I appreciate the insight. I think coffee people are on a higher level than wine people, FWIW. It is a _far_ more nuanced beverage.

As an engineer and a lover of coffee with a barista certificate...

* soil,

* climate,

* harvesting process (for example, you get different results if have somebody harvest by hand the ones that are ripe vs when you send a machine to harvest an entire side of a hill),

* fermentation/preparation process,

* roasting process,

And that is before even you choose what you do with your beans. Any grinding, brewing method will produce potentially very different flavour profile because coffee brewing is notoriously sensitive to minute changes in grind sizes, grind size consistency, temperature, pressure, duration, level of flow of water through the grinds, etc.

And then the question of how much you dilute the brew or what you add to it.

You can get very different results from two different processes:

a) make espresso into the cup, pour milk, add ice

b) put ice into the cup, make espresso over the ice, pour milk onto it

which is exact same ingredients, just a different order.

You can get the coffee to taste very, very differently based on what you put in your mouth before you drink the coffee. Try drinking a sip of coffee, then put a piece of cake in your mouth, eat the piece, then make another sip of coffee. You will find the coffee now tastes completely different.

The dimensionality of the space of all parameters is enormous.

You just beat me to it. The headline author (on editorial side, not the researchers), sadly leans on the genes-are-all crutch and forgets entirely about the massive contribution of multiple fermentation steps.
Quick ctrl-F reveals no mention of the word "grape" or "barley" in the article.

Nobody is surprised that genetically-similar grapes grown in different regions and converted to wine using different processes taste different. Same goes for barley and beer, apples and cider, et al. Why should we be surprised at all that it also happens with coffee?

Plus, small genetic differences can result in large physiological differences in the actual organism. Just look at broccoli and cauliflower, for example. Or domestic dogs, or humans.

And blending. E.g. the same as with the wine. There are only number of wine grapes (Cabernet Sauvignon, Merlot, Shiraz etc) but every wine is different.
How/where do you get a barista certificate?
My wife gifted a course for me for my birthday. We know it was a little bit selfish (to get me to learn fancy coffee drinks rather than chase perfect espresso), but I enjoyed it and I learned a lot. It was directed at people who will actually be working professionally and I learned a lot of stuff I would not have learned otherwise.
Weather, elevation, rain frequency and bacterial content in the soil makes such a big difference. That's why coffee from Colombia tastes so dam good.
I wish I could do an indoor vertical farm just for beans, to get them exactly the way I want them. I know, a single espresso would cost me maybe $5 if doing it this way, but it could be a nice hobby.
The headline isn’t the original paper authors’ fault, rather the news side of the Nature editorial office. Sadly it leans on an all-to-prevalent crutch and oversimplification of the genetics field. A large component of coffee taste comes from processing after picking, which includes several fermentations. Massive flavor swings occur here, but are left unmentioned. Not everything is in genes .

We don’t even need to discuss roast and brew chemistry.

Best example of this are the coats of cloned cats. Genetically identical but they look very different. Nature vs. Nurture is an old question but it's hard to appreciate the things that nurture encompasses that on the face might seem purely "Nature."