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How Much Caffeine is in a Cup of Coffee?

amount of caffeine in coffee

If you came here to read superficial content recycled from numerous coffee-related blogs, then feel free to stop reading. We decided to conduct our own research and read through numerous scientific articles and journals.

Now, there isn’t a definite answer to the question of how much caffeine is in a cup of Coffee? A lot of factors come into play- the type of coffee beans, the extraction process, type of coffee machine, etc. However, chemists and other scientists came to an ingenious way of determining the average amount of coffee in drinks that contain caffeine.

Simply put, Gilbert and his colleagues, as far back as 1976, took samples of people’s beverages, and later tested them. This way, they were able to determine the average amount of caffeine in drinks like coffee and tea. We will talk about this and other articles a bit later, and now we will briefly examine everyone’s favorite chemical – caffeine.

Caffeine Explained

According to the Journal of Analytical Toxicology, caffeine is the world’s most popular drug. Yes, caffeine is a drug, as it alters neurological and psychological functioning. Along with some other, more sinister chemicals (amphetamine, cocaine) it is classified as a stimulant, which means that it gives you a little push when you’re tired.

Needless to say, caffeine is one of the mildest stimulants, which is why it is so widely consumed- for instance, 90% of USA citizens consume caffeine on a daily basis (later we’ll see why, and why this might be a big problem). One of the reasons caffeine is everyone’s drug of choice is that serious caffeine-related addictions are practically inexistent.

You won’t see a man who’s so addicted to caffeine that he neglects every other aspect of his life in order to pursue his addiction. This is why the American Psychiatric Association didn’t include caffeine addiction in the newest version of the Diagnostic and Statistics Manual.

We have to be specific here- one can get really get so used to coffee (or other beverages with high caffeine levels) that withdrawal symptoms (headache, sleepiness, etc.) appear as soon as the consumption is stopped. However, the full clinical picture of addiction seldom, if ever, appears. This doesn’t mean that you can drink as much coffee as you want- if you drink 50 cups of black coffee, you will probably die.

Most of the caffeine consumed comes from seeds of Coffea plant– even though they are mistakenly referred to as coffee beans, which they are not. We won’t bother you with the chemical intricacies of caffeine- this is a highly complex chemical and it affects the human body in numerous ways. The most important effect is linked to adenosine and its receptors in the brain. Adenosine is the so-called “tiredness neurotransmitter”, as it tells your brain that you need rest. More specifically, caffeine precludes adenosine from binding to its receptors, which in turn “fools” your brain into believing that no rest is needed.

This is not the only effect. For instance, caffeine alters the functioning of autonomic nervous system (and, most prominently, sympathetic nervous system)- it increases your blood pressure and heart rate, for example.

We’ll now give a short list of the most important effects:

  • Blocks adenosine receptors- this neurotransmitter tells your brain that it needs sleep and rest. You feel less tired and drowsy.
  • Increases heart rate
  • Increases blood pressure
  • Helps with memory consolidation
  • Concentration

On the other hand, one coffee too much may affect you negatively:

  • Nausea
  • Vomiting
  • Irritability
  • Nervousness
  • Anxiety
  • Insomnia
  • Irritable bowel syndrome or other problems with digestion

These were all psychological side-effects of caffeine. However, if you have some medical condition, ingesting too much caffeine may result in serious problems- heart attack, high blood pressure, etc.

Amount of Caffeine in Coffees (Espressos, Latte Macchiatos, Cappuccinos, etc.) and Other Beverages

The following table is based on the data McCusker and her colleagues obtained in their study:

Type of Drink Amount of caffeine per cup/shot (mg)
Big Bean Espresso 75.8
Starbucks espresso, regular 58.1
Starbucks regular 259.3
Dunkin’ Donuts regular 143.4

Note that these figures are only averages. McCusker noted that amounts of caffeine vary even in the same drink. For example, the amount of this chemical in Starbuck’s Breakfast Blend ranged from 259.2 mg to 564.4 mg in 6 consecutive days. In other words, even beverages made in highly standardized and rigorous environments can have a big variation of caffeine percentage.

Some other studies examined other drinks:

Type of Drink Amount of caffeine per cup/shot
Latte macchiato 63-175
Instant coffee 27-173
Tea 8-91
Einstein Bros Double Espresso 185

Reissig (Drug and Alcohol Dependence Journal) noted that energy drinks sometimes have a higher dosage of caffeine than beverages like espresso or latte- some energy drinks have a whopping 500 mg per can. Furthermore, decaffeinated drinks actually contain a little bit of everyone’s favorite drug, but this percentage doesn’t usually surpass 20mg per cup.

Different Sorts of Coffee Beans

By far Arabica species is most widely consumed- it has many varieties that have special scent, flavor, and aroma. All countries that produce coffee (Brazil, Vietnam, and Colombia being the 3 biggest producers) have a multitude of varieties. This means that possibilities are practically endless- each landscape produces different flavors, and it is simply impossible to taste them all.

Moreover, one of the most popular strains is the so-called Java, first bred on eponymously named island in Indonesia. This variety of coffee has become so popular that “Java” is sometimes used as a slang term for coffee.

Robusta species is the second most popular coffee species in the world. Vietnam is its biggest producer, as practically all Robusta beans come from this little country. Robusta beans have more caffeine- no wonder Vietnam thrives and constantly gets better! So if you are a big coffee lover and traveler, don’t hesitate to go to Vietnam. Moreover, in this part of the world, you’ll be able to find some of the most expensive coffee beans in the world- Kopi Luwak (civet coffee)- these beans were ingested by common palm civet (small mammal) and passed through its digestive system. As a result, these beans have a special flavor that cannot be imitated.

Methods of Coffee Brewing

Amount of caffeine also depends on the way you prepare your coffee. We’ll now briefly describe the most popular coffee-extraction methods, and examine some differences:

  • French press – this is a fairly simple method – coffee grounds are mixed with hot water, after which the residue is pressed out. This method “yields” mild to moderate coffees in terms of strength.
  • Drip methods (automatic and pour-over) – the most important thing about these methods is the utilization of a filter. You can choose the one that suits you the most. The automatic technique usually produces mild coffee- with respect to caffeine amount and taste. Pour-over method results in a relatively stronger drink (sometimes over 145 mg per cup). Automatic drip method is used for making milder coffee in terms of caffeine levels- 100 mg per cup.
  • Turkish – this technique has a lot of names- Greek, Balkan, Bosnian, etc., suggesting that people living in this area absolutely love it. This is one rather straightforward method- coffee is mixed with boiling water in a brass pot. As no filters are used in the process, the Turkish method usually results in strong-flavored, acidy coffee. This is why something sweet is usually consumed while you sip on this kind of coffee. Caffeine-wise, this is a rather strong drink- containing more than 200 mg per cup.
  • Percolating – this method is a part of history, but it’s worth mentioning. For this, you’ll need a special stove that has 2 separate chambers. The steam coming from the boiling water in the lower chamber passes to the second chamber. Coffee grounds are between the two chambers so the steam can extract them while passing through. Although this is an obsolete method, it still packs a punch- as coffee made by percolating method contains 200 mg of caffeine per cup.

According to Food and Chemical Toxicology, percolating and drip (automatic)  methods yield the same amount of caffeine per cup- 80 mg approximately. Espresso is perhaps the most “potent” of all, as it contains 60 mg per one serving- needless to say, espressos have the smallest servings, which is why this is the most concentrated form of coffee.

How Much Caffeine is too Much

Most physicians generally agree that a daily dose of caffeine shouldn’t surpass 400 mg. As most Americans use automatic drip method, this equals about 4 cups per day.

However, we’ve seen that amounts of caffeine vary even in standardized, commercial drink companies like Starbucks make. So just keep this in mind.

Most specialty coffees have much more caffeine than the ones you would make at home- especially the ones made from Robusta beans. Coffee made from these beans will have twice as much caffeine compared to beverages made from Arabica.

Finally, people with heart diseases (tachycardias, arrhythmias, etc.), and stomach problems- acid reflux, Chron’s syndrome, irritable bowel syndrome, should think twice before brewing yet another cup of coffee. Their medical conditions will probably be aggravated even by moderate caffeine intake.