Coffee is the second most consumed liquid in the world after water, and it is estimated that humans drink 400 billion cups of it per year. The secret of coffee lies not only in its flavor and aroma, but also in its caffeine content, a natural stimulant that helps improve alertness and concentration.
However, not all coffee is created equal when it comes to caffeine content. Factors such as bean variety, origin, cultivation, roasting process, grind, and extraction method greatly influence the amount of caffeine in a cup of coffee. There are many myths about the caffeine content of coffee. Many people assume that “strong” coffee made from dark roast beans (or horrible roast beans) contains more caffeine than other roasts. In reality, the opposite is true.
Caffeine content of coffee
Caffeine is a naturally occurring alkaloid found in many plants, including tea leaves, guarana berries, and of course, coffee beans. In coffee, caffeine acts as a natural defense mechanism against herbivores and some pests. In animals, caffeine blocks a brain chemical called adenosine, which, when its concentration increases, sends a message of fatigue and sleepiness. Coffee does not wake us up, but rather prevents us from realizing that we are tired.
Interestingly, coffee is a fruit, more precisely a berry, and coffee beans are the seeds of that fruit. The amount of caffeine in coffee beans can vary greatly from one variety to another.
Coffee varieties
There are two main species of coffee grown in the world: Arabica Coffee And Canephora Coffeebetter known as Robusta. The Robusta variety contains about twice as much caffeine as Arabica.
While Arabica beans typically have a caffeine content of between 1.2% and 1.5% of their dry weight, Robusta beans contain between 2.2% and 2.7%. This significant difference is one of the reasons why Robusta coffee has a stronger and bitter taste compared to Arabica.
Specialty coffee is almost always Arabica, while cheap coffee found in the supermarket is usually mostly Robusta.
Origin and growing conditions
The caffeine content of coffee beans is also influenced by where the plant is grown. Factors such as altitude, climate, soil quality, and farming practices can affect the amount of caffeine in the beans. Generally, coffee beans grown at higher altitudes tend to develop a more complex flavor profile, but do not necessarily contain more caffeine. For example, Ethiopian coffees, which are typically grown at high altitudes, are known for their fruity and floral flavors, but are not known for their high caffeine content.
Roasting process
Coffee roast also plays a role in caffeine content. Contrary to popular belief, the roast degree does not significantly affect the amount of caffeine in the bean. Light and dark roasted coffee beans contain similar amounts of caffeine. The difference comes from another factor: weight. Dark roasted beans have become more dehydrated and less dense. Due to the density of the beans, light roasted coffee may contain slightly more caffeine by volume, while dark roasted coffee may appear to contain more caffeine by weight.
Ground coffee
The grind size affects the surface area of the coffee bean that comes into contact with the water during extraction, which can influence the amount of caffeine dissolved in the beverage. A finer grind, such as that used for espresso, exposes more surface area of the bean, allowing for faster and more efficient caffeine extraction. In contrast, a coarse grind, such as that used in a French press, extracts caffeine more slowly, but this does not necessarily mean that it will contain less caffeine in the final cup. Again, this is a factor that depends on the amount of coffee used.
Extraction method
The method of brewing coffee is one of the most important factors that determine the amount of caffeine in the cup:
- Filter Coffee: This is one of the most common methods and its caffeine content is usually around 95 mg per 240 ml cup. The amount of caffeine can vary depending on the proportion of water and coffee, as well as the extraction time.
- Espresso: Although an espresso has less volume (around 30-50 ml), it is more concentrated and contains between 63 mg and 75 mg of caffeine per serving.
- Coffee Plunger: This method produces coffee with a similar caffeine content to drip coffee, but a longer extraction can result in a higher concentration.
- Turkish Coffee: This type of coffee is unfiltered, allowing sediment to remain in the cup. As a result, it contains a high amount of caffeine, up to 100 mg per small 60 ml cup.
- Cold infusion: It is prepared by steeping ground coffee in cold water for several hours and has a high caffeine concentration due to the long contact time between the water and the coffee. An 8-ounce cup can contain between 150 and 240 mg of caffeine.
The way coffee is stored greatly influences its aroma, but not so much its caffeine content, since it is a fairly stable compound. However, to preserve the greatest amount of caffeine and preserve the quality of the coffee, it is advisable to store the beans in a cool, dry and dark place, preferably in an airtight container.
