There are certain things in life, that are immeasurable at the stakes of delight – like the cool gust of wind on a hot summer day, or the orange hue spreading across the sky at the break of dawn, or my personal favorite – the earthly aroma of freshly ground coffee.
Coffee in today’s world isn’t only one of the most popular beverages but is also one of the most profitable commodities in the world.
So, with this article, let us dive deeper into the science of this brewed beverage that had taken the world by storm around a thousand years ago and thus has never relented it’s hold upon us, ever since.
Discovery of coffee:
The most popular legend behind the discovery of coffee revolves around a goat herder named Kaldi, who lived in Ethiopian plateau around 850 AD. As the Legend goes, Kaldi used to take his herd of goats to graze in an open field which was filled with a certain kind of bushy trees that yielded strange looking red berries.
During one such expedition, he noticed that his goats on eating those red berries became highly energetic and jumped around more than usual. He reported his observations to the head of the local monastery and bought him the berries that he had collected from those trees. However, the monks disapproved of their use and threw them into the grate of fire. Ironically, roasting the first beans of coffee!
A tempting bittersweet aroma of the baked beans of coffee filled the room, enchanting one and all. And there in the Ethiopian monastery, with half charred coffee beans raked out of fire were crushed into powder, dissolved into hot water – the first cup of coffee was made.
The word about this delicious and energising drink soon began to travel east and first, the trade and then, the cultivation of coffee began in the Arabian Peninsula. By 16th century, the use of coffee was spread from Persia to Turkey to Egypt and Syria. In fact, it was so widely popular that public coffee houses ‘quahveh khaneh’ were build all across the east for the people to enjoy this exotic beverage.
By 17th century, the bitter-sweet drink had spread its reach even further and had entered into the realms of Europe and begun its journey to take the world by storm.
The Coffee trees:
These trees belong to the family Ruibiaceae and genus Coffea and although it’s known to have around 30 species under this genus, there are only two, which satiates the world’s coffee consumption and dominates the international market. The first is, Coffea arabica and the second is Coffea canephora or Coffea robusta.
Coffea arabica is the far off descendant of the first discovered coffee plant in the Ethiopian plateau, and produces the best quality coffee with a mild aromatic smell that has made it a success. C. arabica needs to be grown at least 2000 to 6000 feet above the sea level in a mild temperature and at a place with optimum rainfall.
Coffea robusta as compared to the arabica has around 50 to 60% more caffeine and is far more easier to cultivate, since it doesn’t require very high altitude and is more resistant to diseases and parasites and can also be grown in warmer climates like that of Brazil and Southeast Asian countries.
To aid in harvest of the beans, the trees are pruned short, but under natural conditions a coffee tree can grow up to the height of 9 to 10 meters, but growing coffee beans is a matter of great patience, since even after flowering it takes almost a year for the maturation of cherries and around five years to grow and reach to the stage of fruit production. The harvest of the cherry is an equally long and gruesome process that requires a lot of patience.
Coffee Cherry:
Now one must not confuse the cherries, with the beans that we brew, to make the beverage. Those are actually the roasted seeds, extracted from the cherries or fruits.
The outermost layer of the cherries, is the exocarp followed by a thin mesocarp and then parenchyma that covers it. Inside these three layers, lies two coffee beans side-by-side covered by endocarp for protection. Each of the two beams has a spermocarp which is commonly known as silverskin, covering them.
In certain rare cases, only one bean is found inside the cherry instead of two, because of a natural mutation that leads to the fertilization of only one seed out of the two. This single oval bean which is produced in such a case is known as peaberry. They are manually sorted out during harvest and are sold separately at a higher price because of their enhanced taste.
Composition of coffee:
Coffee is something that has entered and therefore meshed into the intricacies of life and has become a part of it over time. So, here’s what the energizing cup actually contains and how it affects us:
The major constituents of coffee are: caffeine, tannin, carbohydrates, coffee oils, proteins and some acids.
The alkaloids: caffeine and trigonelline.
Caffeine, an alkaloid might well be the reason why we got hooked up to coffee and could not do without it at all. Caffeine as it turns out, is a stimulant for central nervous system.
Within the brain, caffeine acts as an antagonist of adenosine, and binds to the adenosine receptors in the neurons that stops us from feeling fatigue. Caffeine also increases energy metabolism in the brain, along with activating non-adrenaline neurons that releases dopamine.
Trigonelline is another alkaloid found in these beans, although it is present at a slightly less concentration than caffeine. It is this compound which produces the enchanting sweet earthy aroma. Trigonelline starts to decompose at around ~160 °C. So, during the roasting of coffee beans, a process that is carried out at around 160-230 °C, a part of trigonelline is demethylated to produce nicotinic acid and compounds that create the lovely aromas.
Now, after the aroma, coming to the taste of the coffee – one of the molecules that is held responsible is chlorogenic acid. Despite the common confusion at the name of this acid, it doesn’t contain any chlorine. But is named so because of the green colour produced when the acid is oxidised.
When the beans are lightly roasted, chlorogenic acid lactones are formed, imparting the bitter characteristic taste of the coffee. But, when the beans are heavily roasted the lactones are broken down to form phenylindons, that are way more bitter in taste than the lactones, as seen in espresso.
Another compound that lends a helping hand in producing the characteristic taste of coffee is melanoidins, a brown coloured product which is very bitter in taste- formed during the roasting of the beans through the Maillard reaction.
The coffee oil:
In general, all types of seed store a higher amount of lipids within them as an energy source for post germinative growth, as does the coffee beans.
The oils in these mainly consists of lipids like linolenic acid, palmitic acid and a wide variety of triacylglycerols and also volatile compounds and fat-soluble vitamins giving them the creamy texture. In a brew, it is these coffee oils that produces the creamy savoury floating layer at the top of an espresso.
Effect of coffee on our health:
Coffee is a complex mixture of a horde of different chemicals, each having their own functions and since, it’s an open source of Mg2+, riboflavin and chlorogenic acid; it is bound to have some benefits. However, it also has its own pitfalls. So based on a range of experiments carried out through the last two decades, here are some diseases and how consumption of coffee affects them:
1. Cancer: Coffee consists of various types of polyphenols which have been proved effective in stopping cancer growth in animal tissues. Furthermore it has been observed that caffeine leads to decrease in estrogen levels, a hormone which is related to several types of cancers.
2. Type 2 diabetes: A few years ago, scientists of Harvard university carried out an analysis of 45,000 people. It showed that increased intake of caffeine over a long time decreases the risk of developing type 2 diabetes as compared with non-drinkers. The hypothesized reason behind this is that the polyphenols and Mg2+ present in the brew may increase the effectiveness of insulin and glucose metabolism.
3. Heart health: In short term, drinking a cup of coffee can help produce- alertness, increase energy levels and decrease fatigue and allows us to concentrate. But for long term- caffeine can have similar negative effects too. Caffeine as we know, is a central nervous system stimulant and in some people it may cause disruption in sleep, increased heart palpitations and sometimes even disrupts the digestive system.
In addition, unfiltered coffee as used in the Turkish brew, French press or espressos- contains a substance called diterpenes, which can increase bad LDL cholesterol and triglycerides thus leading to heart blockages.
4. Depression: Again, the polyphenols in coffee acts as natural antioxidants that controls oxidative stress and also acts as antidepressants by increasing alertness, increasing the energy levels and reducing the anxiety and agitation.
Conclusion:
India is the 6th largest producer of coffee in the world and the legend behind the introduction of coffee in India is even more interesting. In the year 1670, an Indian pilgrim named Baba budan went to Mecca and returned with 7 smuggled coffee beans from Yemen, at a time when it was illegal to take coffee beans out of Arabia. Those beans were planted in Chandragiri hills of karnataka, a place which is still famous for it. India has around 250,000 coffee growers, working in the hills of Indian peninsula- including the states of Karnataka, Tamil Nadu and Kerela.
So, today- coffee, a drink that has thousand years of history behind it, is grown, cultivated and drank in almost every part of the world. Apparently, Cassandra Clare, an american author had appropriately phrased in the City of Ashes – “As long as there was coffee in the world how bad things could be?”
References:
- Nehlig A, Daval JL, Debry G. Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects. Brain Res Brain Res Rev. 1992 May-Aug;17(2):139-70. doi: 10.1016/0165-0173(92)90012-b. PMID: 1356551.
- Harvard school of public health
- A Detail Chemistry of Coffee and Its Analysis
Nice to flip through such an illuminating topic on caffeine ?
Glad you enjoyed it.