For many people, a hot cup of coffee, tea or cocoa in the morning is the perfect way to start the day. However, whether the reason for this is the special flavour of these hot drinks or rather the stimulating effect of the caffeine or theobromine they contain is something that everyone can only answer for themselves.
Coffee, tea and cocoa are so-called stimulants, as they are not primarily consumed for their nutritional value or for satiety, but for their special flavour or effect. In a broader sense, alcoholic products and tobacco products are also considered stimulants - some of us have certainly enjoyed their intoxicating or relaxing effects...
The definition of the term "stimulant" extends all the way to "addictive substance". These terms are not clearly delineated from one another and also vary over time: tobacco, for example, has primarily been considered an addictive substance in Europe since the 1950s, but was previously regarded exclusively as a stimulant and even a remedy for centuries.1)
The stimulating or calming effect of these stimulants is based on the secondary plant substances they contain, which the original plants produce as a defence against predators. These toxic substances, also known as alkaloids (such as caffeine, theobromine and nicotine) have a characteristic effect on the human organism when consumed. The bitter-tasting caffeine, for example, of which a cup of coffee contains an average of 70 mg, leads to an increased release of dopamine and the hormones adrenaline and noradrenaline in the body, which stimulates the central nervous system and energy metabolism, among other things.2a)
But now we come to the plants that give us these stimulants.
Coffee is the seed of the coffee plant. The so-called coffee cherries are green (unripe) to red (fully ripe) stone fruits of shrubs or trees of the Coffea genus from the Rubiaceae family. These coffee cherries usually contain two seeds, the coffee beans, which are first freed from the fruit skin and ideally also from the seed coat (silver skin) and are then used raw, roasted and whole or crushed as coffee after drying. Around 100 different Coffea species are cultivated worldwide, but only 2 of these are of economic importance for coffee production.2b) Almost 99% of total global production consists of the different varieties of Coffea arabica (Arabica coffee) and Coffea canephora (Robusta coffee).3) In the 2023/24 marketing year, around 6.1 million tonnes of arabica coffee and around 4.5 million tonnes of robusta coffee were produced.4)
Originally, coffee plants only grow in the tropical and subtropical zones around the equator, as the plants require a consistently warm and humid climate. However, the trees, which can grow up to 8 metres tall, are usually cultivated in the form of bushes around 2 metres high for easier manual care and harvesting.3) In 2023/2024, the main producing countries are Brazil (39% of the global market share), Vietnam (17%) and Colombia (7%), in addition to the most important producer by far.5)
Arabica coffee thrives at altitudes between 600 and 2,100 metres and is considered to be of particularly high quality due to its slower-growing fruit at these altitudes. It tastes milder and is more digestible than Robusta coffee, which is less sensitive to temperature fluctuations and is therefore also grown at lower altitudes (up to a maximum of 900 metres). The very labour-intensive, time-consuming and costly harvest is usually carried out by hand in several passes, as this is the only way to ensure ripe red cherries and therefore good quality. On large coffee plantations in Brazil, harvesting machines are sometimes used to pick all the fruit from a tree, including the unripe or overripe coffee cherries, in a single operation. If these fruits are not all removed during the subsequent sorting process, this has an unfavourable effect on the coffee quality.3)
The story continues with tea.
According to the Food and Agriculture Organisation (FAO), a good 29.7 million tonnes of tea leaves were harvested worldwide in 2022 on an area of around 5.3 million hectares. China produced 48.8%, India 20.1% and Kenya 7.8% of this amount.7)9)
Tea plants are evergreen trees of the genus Camellia sinensis, which can reach a height of more than 6 metres without cultivation. In tea cultivation, the plants are pruned to form shrubs or hedges to make care and harvesting easier and to promote the development of young side shoots. This is because only the leaf buds, young leaves and young shoots are harvested as tea. In order to obtain high-quality teas, traditional picking methods are still predominantly used today, in which only the terminal leaves or buds that have not yet unfolded and the two young leaves that follow are harvested by hand.6a)
There are two important varieties of Camellia sinensis:
Camellia sinensis var. sinensis: These tea plants are less sensitive to cold and have smaller, harder leaves. The tea is considered to be very aromatic. It is also known as "China tea" as it is mainly grown in China (but also in Darjeeling in India). The plants thrive at altitudes of up to 2,500 metres and can live for 120 to 140 years.7)
Camellia sinensis var. assamica: These tea plants are sensitive to cold and dry conditions. They have large leaves and a high yield. The tea is also called "Assam tea" because it was discovered in Assam in India. This tea plant dominated the rest of India and Sri Lanka and grows particularly well in the plains or marshland.7)
However, the two pure varieties are being pushed back more and more worldwide, as tea plants grown today are mostly hybrids of both varieties.7)
And what determines whether Camellia sinensis tea plants produce black or green tea? On the treatment of the tea after harvesting - this is what gives rise to the different types and flavours!
Black tea is fully fermented, dried tea. After initial drying (withering) of the green leaves, they are rolled under slight pressure to destroy the cell structure of the leaves. The secondary ingredients, which were previously strictly separated from each other in the intact tissue, now meet the enzymes present in the cytoplasm and organelles and react with each other. These oxidation and fermentation processes produce the typical aromas and the characteristic dark brown to black colouring of the leaves. The fermentation process is finally halted by thermally destroying the enzymes by exposing the tea leaves to an 80-110°C air stream and drying them.6a)8)
Green tea, on the other hand, does not undergo a fermentation process. Steaming destroys the tea's own enzymes in the young leaves and shoots so that fermentation does not take place and the leaves retain their pale green colour. Green tea contains more tannins than black tea and the infusions are light in colour and taste aromatic and tangy. 8)
If the withered tea leaves are rolled and only briefly fermented (= the fermentation process is interrupted prematurely by drying), the result is an intermediate product between green and black tea, both in terms of production and flavour: Oolong tea.8)
White tea is considered to be particularly fine, as only the unopened leaf buds of the tea bush are picked individually by hand. As with green tea, there is no fermentation process. And as white tea does not become bitter, the leaves can be infused a second time with hot water. However, the second infusion tastes very different to the first.8)
Let us now turn our attention to cocoa - another product that is still mainly harvested by hand using traditional methods.
Cocoa plants are trees of the genus Theobroma cacao L. and only thrive in the warm and rainy tropics. Cocoa trees can grow up to 15 metres tall, but their growth is limited to around six metres to make harvesting easier. Depending on the country of cultivation, the trees bear 20 to 50 cocoa fruits, each with 25 to 50 egg-shaped, purple or reddish seeds, the cocoa beans. To remove the slight sharpness and bitterness of the raw cocoa beans and to develop the special cocoa flavour, the seeds are first fermented together with the sugary pulp and then dried. Cleaned and packed in sacks, the cocoa beans are then traded and shipped as raw cocoa on the world market. In the buyer countries, the first step in further processing is roasting. The cocoa beans are then freed from their shells and seedlings in so-called breaking machines. Grinding the roasted cocoa nibs melts the fat, the cocoa butter, and produces a sticky liquid, the cocoa mass. These are the starting products for chocolate, for example. If the cocoa mass is also de-oiled hydraulically, a press cake remains, which is then ground into cocoa powder.10)11)
The cocoa tree was cultivated by the Maya in Central America as early as around 300 AD to produce a stimulating chocolate drink from the caffeine- and theobromine-containing seeds of the cocoa fruit (Mayan language: cacahuatl = cocoa water; chocolatl = hot water).6b)
However, cocoa beans were not only considered a luxury food, they were also a commodity, cult symbol and means of payment. And probably even beyond the time of the Aztecs (1325 - 1521 AD). After the discovery of the "New World", the Spaniards brought cocoa from there to Europe, where it was initially reserved for the nobility and the wealthy bourgeoisie.2c)
With the spread of cocoa consumption in Europe in the 17th century, the cultivation areas were also expanded accordingly.6b) According to the FAO, a total of almost 5.9 million tonnes of cocoa beans were harvested on around 11.9 million hectares of land worldwide in 2022. Of this, 69.9% of cocoa beans came from Africa, 15% from South America and 12.1% from Asia. The 10 main producing countries harvested 93.7% of the total volume in 2022. Côte d'Ivoire led the way with 2.23 million tonnes (38%), Ghana with 1.11 million tonnes (18.9%) and Indonesia with 0.67 million tonnes (11.4%).11)12)
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Our next article is about spices.
References:
1) Cf. Wikipedia, 2024: Genussmittel, taken from the internet on 04.07.2024, https://de.wikipedia.org/wiki/Genussmittel
2) Rimbach, G., Nagursky, J., Erbersdobler H. F., 2015: Lebensmittel-Warenkunde für Einsteiger, 2. Edition, a) page 289, b) page 283 ff., c) page 302, Springer-Verlag, Berlin Heidelberg, ISBN: 978-3-662-46280-5
3) Cf. Bundeszentrum für Ernährung, 2024: Kaffee: Erzeugung, Anbau in tropischen Ländern, taken from the internet on 12.07.2024, https://www.bzfe.de/lebensmittel/vom-acker-bis-zum-teller/kaffee/kaffee-erzeugung/
4) Cf. Statista, 2024: Kaffeeproduktion weltweit nach Sorten in den Jahren 2018/19 bis 2023/24, taken from the internet on 12.07.2024, https://de.statista.com/statistik/daten/studie/224824/umfrage/weltweite-kaffeeproduktion-nach-sorten/#statisticContainer
5) USDA - U.S. Department of Agriculture, 2024: Production - Coffee 2023/2024, taken from the internet on 12.07.2024, https://fas.usda.gov/data/production/commodity/0711100
6) Lieberei, R., Reisdorff, C., 2012: Nutzpflanzen, 8. Revised edition, a) page 288 ff., b) page 295, Georg Thieme Verlag KG, Stuttgart, ISBN: 978-3-13-530408-3
7) Cf. Wikipedia, 2024: Tee (Pflanze), taken from the internet on 12.07.2024, https://de.wikipedia.org/wiki/Tee_(Pflanze)
8) Cf. Bundeszentrum für Ernährung, 2022: Tee, Blatt für Blatt feines Aroma, taken from the internet on 12.07.2024, https://www.bzfe.de/lebensmittel/lebensmittelkunde/tee/
9) Cf. fao.org, 2024: FAOSTAT - Crops and livestock products, tea leaves, all countries, area harvested & production quantity, year 2022, taken from the internet on 13.07.2024, https://www.fao.org/faostat/en/#data/QCL
10) Cf. Bundeszentrum für Ernährung, 2022: Kakao, Von der Bohne zum Kakaopulver und zur Schokolade, taken from the internet on 13.07.2024, https://www.bzfe.de/lebensmittel/lebensmittelkunde/kakao/
11) Cf. Wikipedia, 2024: Kakaobohne, taken from the internet on 14.07.2024, https://de.wikipedia.org/wiki/Kakaobohne
12) Cf. fao.org, 2024: FAOSTAT - Crops and livestock products, cocoa beans, all countries, area harvested & production quantity, year 2022, taken from the internet on 13.07.2024, https://www.fao.org/faostat/en/#data/QCL