9 min

This very term can bring its aroma and flavour to our minds instantly. It is a part and parcel of everyday life for most of us. The very sight, smell or thought of a cup of coffee can send tingles throughout the body. Frankly, most of us would be craving a cup at this point. Meanwhile, we read a lot of things about this beverage in our day to day life. In this article, we’ll learn about the amazing aspects of coffee and its effect on the human body, the various ingredients, and approach it in a wholesome manner.


Coffee is a beverage that has a worldwide fan base. Its trade exceeds 10 billion US dollars. Once, this beverage was introduced as an economic crop during the fifteen’s. Further, over 100,000 metric tons of caffeine are consumed around the world every year. Above all, it’s the world’s most widely used drug.

Further, coffee is not the only source of caffeine. On the other hand, beverages like tea, sodas, chocolates, caffeine pills and decaf also contain sizable amounts of caffeine.


One main reason that most of us can’t keep our hands off this beverage is its way of keeping us up and alert. Let’s try to understand the actual mechanism by which it can make us do that. Firstly, the caffeine in coffee helps us feel alert, focussed, happy and energetic even without enough sleep. Consequently, it can also make us feel anxious and raise our blood pressure.

Firstly, in the human body, caffeine acts as a stimulant for the central nervous system. Its tendency to keep us awake is by blocking one of the body’s key-sleep inducing molecules (adenosine). ATP is a high energy molecule produced to provide a constant energy supply to the body. Adenosine is ATP’s chemical backbone.

Our neurons have a perfect fit tailored for these molecules. Further, when adenosine fits into these receptors, it activates a series of biochemical reactions. This causes the neurons to work more sluggishly. Moreover, this slows down the release of certain important brain signalling molecules. Further, this makes us feel sleepy.


Caffeine is an adenosine receptor antagonist. It can derail this process by blocking adenosine receptors. Further, both caffeine and adenosine’s molecular structures look alike. Caffeine can wedge into adenosine’s receptors. But, not close enough to activate the receptors. To clarify, this subtle difference in their molecular structure can bring a huge difference in our bodies.

To clarify, adenosine inhibits your neurons. Whereas caffeine inhibits the inhibitor and thus stimulates you.


Ever felt optimistic, cheerful and satiated after a good cup of coffee. Nope, it not coffee’s magical spell. Further, all these have underlying reasons.

Some of the brain’s neurons have adenosine receptors that are also linked to another molecule called dopamine (paired receptors). Dopamine is a pleasure hormone. When adenosine docks into one of these paired receptors, it’s hard for dopamine to fit into its own sweet spot. Further, this interrupts the dopamine’s mood-lifting work. But, when caffeine sits in one of these paired receptors, dopamine can easily slide in without much effort. Above all, this unhindered path for dopamine is one main reason for the pleasure we experience after a cup of coffee. Further, this is also the main reason for addiction.


  • The effect of caffeine on the adenosine and dopamine receptors can have long term health benefits too. Further, this can reduce the risk of diseases like Parkinson’s, Alzheimer’s and even certain types of cancer.
  • Secondly, caffeine can also provide a kick-start to the body’s ability to burn fat.


Most of us have a lot of questions about this beverage which we consume on a regular basis. Let us try to answer some common questions.

Best time for a cup of coffee?Anytime between 9 to 10 in the morning. In this way, we tend to get the maximum effect of caffeine in terms of how functionally it affects us. Likewise, we can also get the caffeine out of our system by sleep time.
The safe quantity of caffeine to drink?
An Australian study shows, that almost 8 and a half cups of coffee are needed to see any appreciable effect on the heart rate (as of expresso). Further, to get an equivalent amount of caffeine to that toxic limit, almost 25 litres of coffee is needed (filter coffee). This doesn’t necessarily mean we can consume up to this limit.
Does caffeine extract first?No, technically in both caffeine and expresso caffeine is only about 20%. This means that almost 80% of caffeine is still left in the coffee grounds. So running your coffee machine for longer does increase the amount of caffeine in the cup.

Questions concerning the preparation and roast,

Does caffeine extract first?No, technically in both caffeine and expresso caffeine is only about 20%. This means that almost 80% of caffeine is still left in the coffee grounds. So running your coffee machine for longer does increase the amount of caffeine in the cup.
The brewing method that brings in the most caffeine?Between expresso and filter, expresso has the most concentration of caffeine per serve. But, this is controversial. It largely depends on the coffee roast (Robusta and the amount of water used etc.). For example, a double shot espresso contains about 80 mg compared to batch brewed ones that have 125 mg.
Which roast type has more caffeine?Frankly, all types are equally the same. It does not make a huge difference. Be it light, medium or dark roasted coffee, the caffeine content is the same. The solubility of the caffeine is unaffected. The molecule size doesn’t bring much of a difference


There are almost 30 different types. Yup, all these are pretty distinct from one another.

Basic or the primary types:

Classic black Durban, South AfricaPlain coffee and water with no added milk or flavours
EspressoItalyGrounded coffee beans are basic. In addition, high-pressure steam is passed through
Ristretto Italy These are regular espressos with the amount of water halved. Moreover, the final product is usually a concentrated espresso with a different taste.
The long blackAustralia and New ZealandPredominantly, Ristretto -2 shots, espresso and water
AmericanoItaly The base is usually espresso. Water plays a major role in this type. In other words, it is added in large quantities to weaken espresso and increase the quantity of coffee.
The pour-over GermanyGrounded beans are constantly surrounded by water that refreshes them. Further, it contains three phases namely melting, dissolution followed by diffusion. Above all, a filter, ground coffee and a dripper are necessary.
Drip typeGermanyIt is a slow process, but the end product is usually stronger than espresso. Usually, a filter is used in the preparation. Involves, boiling water and ground coffee mixed together that’s made to pass through a filter
The doppioItaly Doppio means double. It is a double espresso shot. Further, it’s prepared through a filter process
The batch brewAmerica and Asia It is the modern version of drip coffee. Meanwhile, it’s economic and easy to prepare
Instant coffeeFranceThe regular coffee. Often a blend of coffee and chicory in different ratios. The most common being 80% coffee and 20% chicory and 60% coffee and 40% chicory. Usually considered bland and distasteful. This can be spiced up with preparation methods like dalgona coffee.

Further, the other basic types include,

Aerospace coffeeOslo, NorwayPaper or metal filters fitted into tubes are used. The coffee is steeped and pressed through the filter. This gives a very distinct taste
Vacuum coffeeBerlin, GermanyHas 2 vessels, the upper one contains the powder and the lower one contain water. The water is brewed and the coffee descends and collects in the lower filter
Immersion coffeeFranceCoarsely ground coffee leaves are soaked in near-boiling water for not more than 5 minutes. This coffee is prepared with great care.

Milk based types:

These include the types like Latte, Caffe breve, piccolo latte, macchiato, latte machiatto from Italy. The popular mocha or mochaccino from Yemen and cortado and Gibraltor from Spain and San Francisco respectively.

Iced or cold variants:

Kyoto or cold brew
Japanese iced variant
Nitro Texas and Portland
Espresso foam (Crema) San Francisco

Exotic varities:

These are not commonly consumed and the base ingredient might include liquor, exotic nuts, berries and even animal poop in types like kopi luwak!

The varieties include Irish (Whiskey, sugar and hot coffee), Italian affogato, geisha of Ethiopia, Cascara, bulletproof, Vietnamese and Turkish.


DRINK (240ml / 8oz)CAFFEINE CONTENT (In mg)
Decaf coffee (Filter)5-10 mg
Black tea30-80 mg
Hot chocolate5-12 mg
Ordinary or filter coffee100-200 mg


Just like any other substance, coffee is extremely addictive. Our brains can adapt very well to the regular consumption of caffeine. If the adenosine receptors of the brain are clogged forever with regular consumption of caffeine, the body will provide extra ones.

Therefore, even with caffeine around, adenosine can still perform its job of signalling the brain to power down. This is the main reason we find the need to consume more and more caffeine, just to feel alert. Also, there are more and more adenosine receptors to block.

If we suddenly quit caffeine, we might experience an unpleasant withdrawal. Further, with plenty of competition and no competitors, adenosine can work overtime.


One tablespoon (14.2 Grams) of pure caffeine is almost equivalent to consuming 75 cups of coffee at once. This can have lethal complications. So, just like any other withdrawal, caffeine withdrawal includes,

  • A very unpleasant sensation
  • Constant headaches
  • Tiredness or fatigue
  • Depressed moods or feelings of blues


  • As we already saw, caffeine can raise the body’s blood pressure and heart rate. This can cause increased urination and diarrhoea.
  • This can greatly contribute to insomnia and anxiety.
  • Too much caffeine in our system causes, migraines, insomnia, nervousness and muscle tremors.


Our body is an amazing thing and always fascinates us with its marvellous ways of self-correction. Similarly, in a few days, the extra adenosine receptors in the body will disappear. Further, the body will re-adjust and we will feel just as alert and awake as ever even without an infusion of the world’s most famous stimulant.

To sum up, coffee is a really tempting and addictive beverage. Anything in moderation is good for the body. Always try to limit your intake to the most ideal hours and never take a cup close to bedtime. So, having known a lot about this favourite and popular beverage, try your favourite flavours but also maintain moderation.

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Dr Kavitha M

I am an undergraduate degree holder in dentistry. I have a great interest in music and reading. I am a linguaphile. My areas of interest lie in psychology, medical imaging, diagnostics, and oncology. I am a person who focuses more on the emerging areas of forensics.


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