Have you ever stopped to think about how much caffeine is in coffee? We tell you everything about this substance and its amount in your cup of coffee, which depends on multiple factors.
Caffeine is one of those substances that has conquered the world. It’s everywhere, usually as part of coffee. Because of its importance, we are going to talk about some of its most intimate secrets: how much caffeine is in a coffee?
The truth is that it is impossible to answer with absolute accuracy due to many different questions: how you make the coffee, what type it is, the process involved… But that does not mean that the question cannot be answered with the aim to be practical. Let’s discover what the grains of this product hide.
What is caffeine
Caffeine is an alkaloid substance from the xanthine group. It is produced by plants as a means of defense against attack by insects and various pests. It is also a stimulant of the central nervous system and the cardiovascular system that is present in coffee beans, tea leaves, cocoa seeds, and other foods.
Caffeine blocks the effects of adenosine, a substance that inhibits neurotransmitters that produce arousal, resulting in increased alertness and reduced fatigue. In other words, caffeine does not give energy but rather prevents the substance that reduces the signals that keep us alert and awake from performing this function, so the energy we have, so to speak, lasts longer.
How much caffeine is normally in a coffee?
A cup of coffee, in general (and ignoring all the factors that we will talk about later and on which the exact amount depends) contains a variable amount of caffeine depending on the coffee preparation we are dealing with. If we look at the most common:
- Drip or filter coffee: A typical cup (approximately 240 ml) can contain between 70 and 140 mg of caffeine.
- Espresso: What is known as an espresso shot (approximately 30 ml) generally contains around 63 mg of caffeine.
- Instant Coffee: One cup (approximately 240 ml) usually contains between 30 and 90 mg of caffeine.
Factors on which the amount of caffeine depends
And how much can we find in a coffee? The variations, as we said at the beginning, vary greatly depending on various factors:
Coffee Variety
The concentration of caffeine in coffee beans varies depending on their species and origin. There are species that have more and some even have very little or no caffeine content, as we can see in the following list, where you will see the caffeine content by weight according to the total weight of the grain:
- Coffea canephora (Robusta): 1.7%-4%
- Coffea liberica (Liberica) : 1.2%-1.5%
- Coffee arabica (Arabica) : 0.6%-1.5%
- Coffea eugenioides (Eugenioides): Approximately 0.2%
- Coffea racemosa (Racemosa): Approximately 0.38%
- Coffea arabica var. laurine (Laurine) : 0.3%-0.5%
- Hybrid Coffea arabica and Coffea racemosa (Aramasa) : 0.7%-0.8%
- Coffea charrieriana (Charrieriana): Caffeine-free
Roasting degree
There are people who believe that the roast or color of the bean affects the caffeine content. It is not like this. Dark roast does not mean higher caffeine content, nor less. In fact, caffeine remains relatively stable during the roasting process, although darker beans may have slightly less caffeine due to mass loss (and not because it is spoiled by heat, for example).
However, this question is somewhat tricky. And, if coffee is measured by volume, dark roasted coffee may have more caffeine since the beans take up less and a greater quantity of them is needed to fill a measure. But this does not mean that they have more caffeine. We are simply using more coffee (with less caffeine).
Grinding degree
Caffeine, obviously, is not increased by the physical process of grinding the bean. However, a coffee can contain more caffeine the more ground it is. A finer grind increases the contact surface with the water, which allows you to extract more of this stimulant, in general terms.
Type of preparation or coffee makers
The amount of caffeine also varies depending on the preparation method or the coffee maker we use. For example, espresso has more caffeine per liter than filter coffee due to the process of boiling water washing away the grounds, but espresso cups are generally smaller. If it is left in contact with the bean for enough time, a filter coffee can also achieve a high level of caffeine, but of course, this does not usually happen either.
In short, and as a general rule, the longer the ground coffee is in contact with water, the finer it is, as we said before, and the hotter it is, the more caffeine can be extracted per liter. Sometimes, in the same type of preparation, just changing one of these factors can produce quite different results. The most standardized ones, such as using a mocha coffee maker, or an espresso coffee maker, usually give the most homogeneous results.
Amount of coffee
There is no debate about this: the greater the amount of coffee used, the greater the caffeine content in the final drink. In turn, the more (liquid) coffee you have in the cup, the more caffeine you will also have. For example, another popular belief is that 220 ml of filter coffee (a large glass, for example) has less caffeine than a strong, thick espresso.
This is not because of a question of quantities. There will be more caffeine in 220 ml, by orders of magnitude, than in just 30 ml of espresso coffee, even though espresso produces more caffeine per liter.
Preparation time
As we have said before, the longer the water is in contact with the grind, the more caffeine it can extract. Thus, French pressing, for example, can extract more caffeine than filtering with a V60, for example. Another question regarding time, since we are talking about it, does caffeine degrade?
The main reason for its destruction would be the oxidation of the coffee, but fortunately, this does not occur significantly, neither in the bean nor in the cup. Caffeine is quite stable, so it remains over time, even if we save the coffee or take a while to drink the cup.
How much caffeine is in decaffeinated coffee?
Despite its name, decaffeinated coffee is not completely caffeine-free. The process of decaffeinating coffee involves removing the caffeine from green coffee beans while trying to maintain as many other chemical compounds as possible that contribute to the flavor and aroma. There are several methods to do it, but in none of the cases is it 100% achieved.
Decaffeinated coffee usually contains between 2 and 5 mg of caffeine per cup, depending on the decaffeination process and the variety of the bean.
Curiously, there is a coffee that, without being decaffeinated, does not contain caffeine, since its beans naturally lack it. We are talking about coffee of the Charrieriana variety ( Coffea charrieriana ), although the quantities present in decaffeinated coffee are small enough not to present, in principle, any type of effect. In fact, let’s remember that other foods also contain caffeine in minimal quantities without notable effects.
How much daily caffeine is recommended
Is there a recommended amount of caffeine? Certainly not in the nutritional sense, as can happen with food. On the contrary, the recommended daily amount is more of a limit. Like many other substances, caffeine can be harmful, even for healthy people, if taken in excess (although the amount is quite high).
The evidence suggests that consuming up to 400 mg of caffeine per day, in adults, is safe for health as long as there is no hypersensitivity, no specific metabolic problem, and leaving aside the situation of pregnancy. This is approximately equivalent to four cups of filtered coffee. We will emphasize that sensitivity to caffeine varies between individuals, and some people may experience side effects with lower amounts.
In any case, like everything in this life, with moderation and prudence, it does not entail any danger. It could even have beneficial effects, as evidence from recent years suggests. But we will talk about this another time, with a cup of coffee in between.