What Is The Strongest Type Of Coffee Beans? Highest Caffeine Content

Is normal coffee not doing the trick anymore and you’re looking for the coffee with the highest possible caffeine content per milliliter? Here is how you can get jittery without having to drink large cups of coffee. 

Robusta beans grown at a low altitude have the most caffeine content (up to 50% higher than Arabica beans). Brewing ristretto is the way to get the most caffeine into the least amount of liquid. Brewing ristretto with Robusta beans will yield the strongest possible cup of coffee. 

Below you can find out why Robusta beans have more caffeine and why ristretto is your best bet for a strong cup of coffee. 

Strongest Type of Coffee Beans

There are quite a few brands that advertise their coffee as ‘the strongest coffee in the world’. I have no way to test the caffeine content of all of those beans to see if that’s true but I do know what the common denominator is in those bags. It’s the specific type of beans. 

The most common type of coffee beans in the world is Arabica. Arabica beans have a caffeine content of about 1.7%. The other common type of coffee bean is Robusta. Robusta beans can have a caffeine content of up to 2.5% which is close to 50% more. 

Image of an Arabica bean next to a Robusta bean

So all the coffees that are claiming to be the strongest coffee in the world will be 100% Robusta. That gives you an almost 50% boost in caffeine per cup. 

Coffee beans are a natural product and there are a large number of factors that impact the final taste and caffeine content besides the type. The geographical location, soil conditions, farming techniques, weather, harvesting techniques are some of the most important factors for taste. 

The height a coffee is grown at is important for the caffeine content. In general, the lower the altitude the coffee is grown at, the higher the caffeine content. And Robusta can be grown at lower altitudes than Arabica. 

Suggested: Is Vietnamese coffee Arabica or Robusta?

The word Robusta comes from ‘robust’. Robusta coffee trees are quite a bit stronger than Arabica trees. That means they can be planted in harsher conditions and at lower altitudes. 

Coffee needs altitude to grow properly. At higher altitudes, there tend to be less insects and insects are the largest threat to a coffee plant. 

Caffeine is a natural insect repellent. That means that plants which produce coffee beans with higher caffeine content can still survive and bear fruit at lower altitudes. 

Should you drink Robusta coffee?

You like strong coffee and are now wondering if you should only drink Robusta. There are some pros and cons to it. 

The benefits of Robusta are;

  • Higher caffeine content
  • Cheaper 

They are cheaper because they grow in more places, at lower altitudes (which makes farming easier) and because they can often bear fruit twice a year instead of once a year for Arabica.

The drawback of Robusta is the taste. Most people prefer the taste of Arabica which is why that is the most popular bean. Robusta is often quite harshly bitter and has many dark, rubbery taste notes.  

Suggested: Should you use Arabica or Robusta beans for cold brew?

Strongest Coffee Brew Method

Another way to look at the strongest coffee is by brew method. Of course the absolute amount of caffeine is going to be decided by the type of beans you use. However, the brew method does greatly impact how much of the caffeine gets into the cup. 

Suggested: Does Espresso have more caffeine than drip coffee?

So what is the brew method that gets you the most caffeine per oz.? You might think it’s espresso and you’d be pretty close. It’s something that’s made with an espresso machine but even stronger. 

ristretto is even stronger per ml. than espresso. ristretto is made with the same amount of ground coffee as a shot of espresso but with half the water. The word ristretto means ‘restricted’ because the amount of water is restricted.

That means that you almost get a shot of espresso concentrated in half the liquid. ristretto is thick, syrupy and very strong in flavor. It’s not quite double the caffeine content of an espresso but it does come close and per ml it has more caffeine. 

Image of a ristretto

The average shot of espresso (1oz.) has 55-65 mg of caffeine while a shot of ristretto has 45-55mg of caffeine. But keep in mind a standard shot of espresso is about 1 oz. While a shot of ristretto is only half that. That is if you brew with 100% Arabica beans. If you’d brew those drinks with Robusta beans, the caffeine content would be almost 50% higher. 

You might be wondering why a shot of ristretto still has most of the caffeine of a shot of espresso while using a lot less water. Shouldn’t it be half the caffeine? No, caffeine is actually extracted really easily and most of the caffeine is extracted by the first part of the water and the latter part has a lot less caffeine to extract (but does extract other taste compounds)

If you’re looking for the most caffeine per ml, look no further than ristretto. However, you probably can’t drink too many of them a day since the flavor is also very intense. If you’re just looking for something to get the most caffeine inside of you, normal drip coffee is actually a good way. Per ml drip coffee has less caffeine but you can easily drink much more of it. 


Welcome to CoffeeImproved! Since falling in love with coffee, I've been on a journey to improve my morning cup day by day. That means I've tried many different brew methods, beans and equipment and experimented with all of them to find what I like. This is where I share what I've learned with you.

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