Coffee lovers are countless, but coffee is a plant that still holds many secrets. One of these secrets was recently revealed by a group of Italian scientists who analyzed the genome of coffee varieties and managed to answer a question that concerned connoisseurs and ordinary consumers of the most popular drink on the planet: where does the coffee taste come from?
In fact, according to their recent article in the scientific journal “Nature Communications”, the Italian scientists applied the most sophisticated methods of reading the genome to samples of seeds of the species Coffea arabica (Coffea arabica) from different parts of the world. They found that the differences between them were minimal, which automatically gave rise to the question: “If coffee of the Arabica variety is genetically the same everywhere, how do its different flavors come about?”.
Favorite drink…
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Before moving on to the answer to the question, it is worth giving some information. According to the official data of the International Food Organization (FAO), the harvest of the 10 most active coffee-growing countries (in order of production: Brazil, Vietnam, Indonesia, Colombia, Ethiopia, Honduras, Uganda, Peru, India, Guatemala) reached in 2023 the 8,322,284 tons. If we add to them the production of another 40 countries, which also grow and export coffee, the total amount reached 10 million tons.
25-30 years is the lifespan of a coffee tree. It takes 4-5 years to start bearing fruit and it reaches full production after 7 years.
Of the at least 129 recorded species of the genus Coffee today, two have prevailed in cultivation and by extension also commercially: Arabica and Robusta. The variety Arabica it is considered the “queen” (56%-60% of all coffee traffic), originating in Ethiopia where it first thrived, at an altitude of 1,000 meters and gives coffee with a finer taste than Robusta.
THE Robusta (which is an ancestor of Arabica) is “born” in West Africa but is now overwhelmingly grown in Brazil. It is much more resistant to disease and drought, so its cultivation is considered easier and more economical, while it contains twice the caffeine content of Arabica.
…and vulnerable
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Many people make a living from this plant but at the same time the forecasts for future production do not make the (poor in most countries) growers optimistic. The same goes for coffee drinkers. You see, the simulations and predictions of the future climate until 2050 give a 50% reduction of the lands suitable for the cultivation of the plant, and for Brazil alone this reduction can reach 85% of the current areas.
The riddle of taste
Returning to the question of the taste of coffee, Italian scientists found that the plant that gives us Arabica coffee does not owe its genetic diversity to the creation of hybrids, i.e. combinations of different varieties. Kafea the Arabic itself, has arisen before approx 50,000 years as a hybrid of Coffea robusta and Coffea eugenioides, a much less widespread species.
6-7 months after the petals of its jasmine-scented flowers fall, the fruit reaches maturity.
So why is it that there are now no hybrids of Caffea arabica? It is due to the fact that this variety exhibits the phenomenon of polyploidy, i.e. it contains more than two copies of each chromosome, which makes it difficult to cross it with other types of coffee. (Polyploidy is a phenomenon found in plants, while it is problematic in animal species.)
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As crossovers are rare in Arabica coffee, the plant relies on mutations to renew its genome but also on rearrangements of its genetic material, which may even include the loss of entire chromosomes. The Italian researchers attribute the different taste profiles of the coffee we drink to these latter.
But it is not only the aromatic profile of coffee, but also its resistance (or susceptibility) to diseases that is attributed to chromosomal rearrangements. A typical example is “coffee leaf rust”, which is a constant threat to the coffee trade worldwide. It is a fungus (Hemileia vastarix) that settles in the plant, first causing brown spots on its leaves and eventually drying it up. At the same time he moves to the neighboring plant.
200 billion dollars is estimated to be the turnover from the coffee trade, with an upward trend of 2.2% per year.
The climatic conditions necessary for the growth of coffee trees are precisely those that the fungus prefers for its spread, and many scientific efforts are focused on combating it. With the new detailed mapping of the Coffee genome it is hoped that we will get closer to the solution of this problem as well.
What does the cup “tell” us?
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A coffee can be from the simplest thing in the world to the most scientifically loaded with various specifications.
We choose and drink:
- The temperature at which the grains release more substances is between 92 and 98 degrees Celsius (the Greek should not have started to boil).
- A coarser grind means a faster flow of hot water, thus releasing less caffeine.
- A finer grind allows the water to circulate between the beans more time, so more caffeine.
- In espresso, the coexistence of particles with quite different sizes is considered good. Because with compression, a much more compact mass is created that resists the invasion of hot water, ultimately contributing to it staying longer, ultimately extracting more caffeine.
- Coffee with green, i.e. unburnt, beans. There is this one too, it is prepared like the others, more reminiscent of green tea. It has the highest content of chlorogenic acid (CGA, C16H18O9), close to 543.34 mgr per liter. A strong antioxidant (also found in apples, pears, blueberries, tomatoes).
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