How Does the Roasting Time of Coffee Beans Affect their Caffeine Content?

How Does the Roasting Time of Coffee Beans Affect their Caffeine Content

Do you consider yourself a dedicated coffee drinker but also conscious of the caffeine content? Are you wondering if the type of coffee beans and their roasting time affect the caffeine content of your cup of joe? There are at least four primary types of coffee beans and these are Arabica, Robusta, Liberica and Excelsa. In this article, let us get to know about these coffee beans and if their roasting time affects their caffeine content. 

How does the roasting time of coffee beans affect their caffeine content?

The roasting time of coffee beans does not affect their caffeine content. Although there is a difference in the caffeine content of coffee roast types, it has nothing to do with roasting time but with the way that the coffee beans are measured. 

When you measure coffee by scoops, lightly roasted coffee tends to have more caffeine since the beans are denser than the darker roast. But if you weigh out the scoops, the darker beans tend to have more caffeine since there is less mass. Arabica beans vary in caffeine levels and this will depend on the specific plant species. There is only a minimal variance in caffeine between dark and lighter roasts. 

Contrary to common myth, a dark roasted bean does not contain more caffeine compared to a light-roasted bean despite the stronger flavor. This means the caffeine content for both dark and light roast is the same. Caffeine levels change very little during the roasting time and for variations to happen the roasting temperature should be above 600 degrees Fahrenheit.  Since temperatures are only usually around 470 degrees Fahrenheit, the caffeine content of coffee beans remains relatively stable for all roast levels, regardless if it is a dark or light roast.

What are the factors that affect caffeine content? 

These are the common factors that affect caffeine content:

The coffee beans.

Coffee beans that are commonly available in the market include the Arabica and Robusta. Arabica accounts for up to 70% of coffee production worldwide and tends to have a sweeter and smoother taste. It has flavor notes of sugar and chocolate with hints of fruits or berries. Some of its common varieties are Bourbon and Typica.

Robusta is said to contain twice as much caffeine as Arabica and has a stronger and more bitter taste with grainy or rubbery overtones. 

The brewing method. 

Turkish and cowboy coffee brewing methods provide higher extraction levels. These methods combine ultra-fine coffee grinds with boiling water but with no filtering action. Such methods give the highest caffeine content but also unfamiliar ones. Pour-over methods like the French Press or AeroPress do not give as much caffeine compared to the earlier methods mentioned.

Drip and filter coffee brewing methods are common ones that are used to make coffee at home but they reduce caffeine content considerably. 

Coffee experts also note that the grind size affects caffeine content and that brewing coffee beans with small grind sizes produce coffee with higher caffeine content. Water temperature may also affect caffeine content since brewing with hot water could extract more caffeine from coffee grinds. 

Types of coffee roasts

These are the types of coffee roasts:

1. Light roast  

Light roast coffee beans have a light body with snappy acidity. They retain most of the caffeine as well as the original flavors compared to darker roasted coffee.

2. Medium roast 

Medium roast coffee beans have more body than light roasts and medium brown. They have a more balanced flavor, acidity and aroma. This is also often referred to as the American roast since most Americans prefer it. 

3. Medium-dark roast 

Medium dark roast has a darker and richer color and the beans have some oil on their surface. It has a heavy body compared to the lighter and medium roasts. 

4. Dark roast 

Dark roast coffee beans are dark brown that is almost black already.  Acidity decreases as roasting time is increased which results in its smooth and mellow flavor. The coffee beans have a bold and rich body with an oily surface. 

The roasting process alters the chemical composition, color and physical characteristics of coffee beans. The longer the beans are roasted, the darker they turn. But contrary to what most people believe, caffeine content stays the same during the roasting process.


Avid coffee drinkers have their personal preferences when it comes to the type of coffee bean roasts for their coffee. Some people may opt to go with the light roast coffee grounds since they presume that it has lower caffeine content compared to the dark roast. However, the roasting time does not affect the caffeine content but more with the way that the coffee beans are measured. 

Image: / Shaiith