How Much Caffeine is in a Coffee Bean?
The reason many of us started drinking coffee would have been for that magical compound caffeine that invigorates us and wakes us up in the morning - it was for me anyway.
Although many people's coffee journey then goes beyond the caffeine when specialty coffee is discovered.
But the caffeine content in coffee beans does always spark conversation around health and wellbeing.
So let’s jump in and try to figure out how much caffeine is in those coffee beans of yours.
Why Trust Me?
What actually is caffeine?
Caffeine is a naturally occurring compound found in an a variety of plants which when consumed in its natural form or in a beverage that contains extracted caffeine improves focus and energy levels.
Caffeine blocks a chemical in the brain called adenosine which normally makes you feel tired and sleepy.
Like anything we consume, caffeine should be enjoyed in moderation. Too much caffeine can have negative side effects such as rapid heart rate, insomnia and the jitters.
Coffee, believe it or not, is actually a fruit.
Well it is the seed of a fruit.
Coffee is grown all over the world, with the majority of coffee being grown in within 20 degrees of the equator. A coffee cherry is red in colour, has a fruity outer layer followed by a couple of slimy mucilage layers before you hit the coffee seeds, the seeds are then processed, dried, usually shipped and roasted before we consume them.
Coffee beans naturally contain caffeine as one of their soluble compounds, in fact the whole coffee plant contains caffeine from the leaves to the fruit which can be dried and consumed as a tea called cascara tea. The highest concentration of caffeine in the coffee plant however is in the coffee seeds that once roasted and brewed releases the caffeine compound into the brew.
Caffeine has also been linked to deterring herbivorous animals from eating the coffee plants as well as inhibiting the growth of other plants competing in the area.
Factors Influencing Caffeine Content in Coffee Beans
Type of Coffee Bean
The mg of caffeine in coffee can vary in different types of coffee bean.
There are 4 main types of coffee beans: Arabica, Robusta, Excelsa, and Liberica. Arabica and Robusta make up the vast majority of the coffee beans in the world.
Taking the two main types, there is more caffeine in Robusta coffee beans than in Arabica. You will see Robusta coffee in many dark roast blends and coffee that markets itself as ‘strong’ coffee.
Robusta is easier to grow than Arabica and doesn’t have the complex flavour profiles, so it often tastes strong and bitter too.
Arabica makes up roughly 2 thirds of the overall coffee produced in the world and within this type of coffee there are varieties called ‘varietals’. You may have seen names such as Bourbon, Typica or Gesha on your coffee bag.
Within these varietals there are slight differences in caffeine levels of beans where sometimes scientists have propagated plants with more or less caffeine than usual.
Roast Profile
The roasting process is a factor that has seen a lot of debate over the years.
The general consensus now is that when you look at the coffee bean itself the caffeine content stays exactly the same whatever the roast profile.
So there is the same amount of caffeine in a dark roast coffee bean than a light roast coffee bean. The difference in the caffeine comes when the coffee is ground and you measure coffee as a volume or weight.
This is because the darker the roast the lighter and less dense the coffee bean is so essentially to make up your 20g or coffee say per cup will take more dark roast beans than light roast, hence will contain more caffeine.
Grind Size
The grind size of the coffee bean can also affect the caffeine level of the brew. This is down to the brew method as well.
The finer the ground the larger the surface area of the coffee, the brew water is in contact with more of the coffee which is then able to extract more of the soluble compounds (caffeine), so you will essentially end up with a higher level of caffeine in finer ground brews.
This is to be taken with a pinch of salt though because if for example you grind the coffee too fine you may not be able to extract any coffee as.
How to measure caffeine content
The caffeine content per coffee bean is roughly between 0.8%-1.4% which equates to an average of 1.45mg of caffeine per bean when you take the average weight of a coffee bean as 132.5mg.
This number can obviously vary between types of coffee but is a rough idea of where each bean sits on the caffeine scale.
If you on the other hand are looking to find the caffeine content of a coffee brew that is a much harder question to answer as you then have to add in many more variables such as brew type, grind size and water temperature which can drastically alter the results.
However a rough idea per serving is as follows:
18g coffee per serving = 135 coffee beans = 0.1969g or 197mg of caffeine per serving.
This amount of caffeine is the absolute value of caffeine in the coffee beans though as you have to take into account that not all of the caffeine is extracted.
Therefore a more accurate amount of caffeine per coffee is around 100mg.
This is to be taken as an average as there caffeine content can range from 50mg - 300mg.
Final Thoughts.
It is hard to actually put your finger on the caffeine content in coffee as there are so many variables unlike a can of energy drink that has the exact amount of caffeine displayed oin the label. Like with anything though, moderation is key and a couple of coffees per day have plenty of health benefits too.
FAQs
What is the average caffeine content in a coffee bean?
The average caffeine content per coffee bean is 1.45mg for Arabica coffee. This does differ for Robusta coffee beans which are around the 2.5mg of caffeine mark.
How much caffeine is typically in a cup of brewed coffee?
Typically in a brewed cup of coffee there is around 100mg of caffeine per serving. This can vary wildly depending on the brew method.
How much caffeine is in an Arabica vs. Robusta bean?
There is around 50% more caffeine in a Robusta bean than in a Arabica bean
Do different roasting levels affect the caffeine concentration?
The different types of coffee roast don’t play a difference in the overall caffeine content of the coffee bean meaning that caffeine is not lost during the roasting process. The difference comes when you look at the overall mass and volume of light vs dark roast coffee and the discrepancies in caffeine content.
Is there any caffeine in decaf coffee?
Yes, there is still usually caffeine in decaf coffee beans. For decaf coffee to be classed as decaf the coffee has to be less than 0.3% caffeine.
How does espresso's caffeine content compare to drip coffee?
There is a higher concentration of caffeine in espresso coffee than drip so if you were to take 20g espresso and 20g drip coffee then you would find much more in espresso. Per serving is a hard one to call as there are many different serving sizes and methods.
Sources:
