What Coffee Beans Make the Strongest Coffee?

You may be one of those people that a regular strength coffee doesn’t quite cut it. What you crave is a strong cup of coffee with bold flavor. First, let’s discuss what strong coffee actually means.

There’s often some confusion regarding what a strong cup of coffee refers to. The interpretation of “strong coffee” may mean different things to different people. Interpretations range from the taste of the coffee to the amount of caffeine in contains, or a combination of both. 

Coffee strength is actually determined by the brewing process. Strong coffee is produced by having a higher coffee to water ratio, not necessarily the roast level of the bean. If you’re referring to strength as to the amount of caffeine, then Robusta beans have the highest levels. 

Let’s dig a little deeper into each of the interpretations of “strong coffee” to guide you to make that perfect cup of “strong” coffee.

Table showing the different interpretations of strength when it comes to coffee. First there is the true definition of strength which is water to coffee ratio. This is the percentage of dissolved coffee grounds vs. water in your cup. Next, people define strength as having a higher caffeine content. Robusta beans have the highest content of caffeine. Lastly, people interpret coffee strength by roast level. Although dark roasts are a higher level, this makes them more bitter while the light roasts coffee produce more caffeine.

Strength Related to Coffee to Water Ratio

When strength is referred to as the coffee to water ratio, this is the TRUE definition of strength when describing a cup of coffee. This means what percentage of a cup of coffee is dissolved coffee grounds compared to the amount of water. 

This is similar when measuring the strength of alcohol. For example, if you look at a bottle of whiskey, it will tell you what percentage of the bottle is ethanol. Basically, how strong is it. If you have a glass of wine, it may be 10% or 12% alcohol. The same is true when measuring the strength of coffee. You are describing how much dissolved coffee grounds are actually in your cup of coffee. 

Typically speaking, when using filter coffee, the strength will be anywhere between 1 to 1.5%. The higher the percentage, the stronger your cup of coffee is. 

You can use a refractometer device to test a sample of coffee to calculate the refractive index. Then a coffee focus refractometer will take the refractive index and tell you what percentage of the cup is coffee compared to water. 

To learn more on what is the best coffee to water ratio, click here!

Strength Related to High Caffeine Content

Now that we’ve discussed the true meaning of what strength means when referring to a cup of coffee let’s look at another interpretation of strength. Many people refer to strength as the amount of caffeine in their cup of coffee. The more caffeine, the stronger their cup of coffee is.

Typically speaking, the amount of caffeine in a cup of coffee will correlate to how much was in the beans to start. Along with how well it was brewed.

Robusta has about twice the caffeine content of Arabica beans. While Arabica beans have a lower percentage of caffeine per bean at 1.2 to 1.5%, Robusta beans have about 2.2 to 2.7% caffeine per bean. That’s double the caffeine per bean! The Robusta species is mainly produced in Africa, India, and Brazil.

Now that we’ve determined that Robusta contains the most caffeine per bean, below are some of the highest caffeine content coffee brands on the market today.

I have to warn you about these coffees, though. These coffees are incredibly high in their caffeine content and are only for individuals with a high tolerance for caffeine and can handle more elevated amounts of caffeine. Do not consume them like you would regular coffee.

Death Wish Coffee

728 mg coffee content

Black Label by Devil Mountain

Coffee amount: 1555 mg

Very Strong Coffee

100% Robusta Coffee Beans 1350 mg

Brewing Methods to get Higher Caffeine Content

Besides choosing coffee beans with a higher caffeine content, there are also specific brewing methods that will yield higher levels of caffeine. For instance, any method having longer steep times, such as a French press or Aeropress, will better produce higher amounts of caffeine. The longer it takes for the water to go through the ground coffee, the more caffeine will be extracted.

Since we are on the topic of brewing methods, below is our pick for the highest-ranking French Press and AeroPress. Both are great products that I use in my kitchen.

Strength Related to Roast Level

The third way people use the word “strength” with a cup of coffee is when they are referring to the roast level of the coffee bean.

Often at grocery stores, you’ll see a “strength rating” on the side of a bag of coffee beans. This describes the intrinsic quality of the coffee. So instead of relaying the actual strength of the coffee, it’s identifying the roast level of the bean.

For example, a strength five would be a very dark roast, and a strength two would be considered a lighter roast. These strength ratings on grocery store coffees describe the bitterness or harshness of the flavor of the coffee. It has nothing to do with the actual strength of the coffee.

If you wanted a higher caffeine content, you would like a lighter roast due to it being denser. As coffee beans are roasted, they lose up to 90% of their water content, leaving more minerals and nutrients, including caffeine. For more detailed information on coffee roasts check out our other article Which Coffee Roast is the Strongest?

On the other hand, if you are referring to boldness when it comes to strength, then a dark roast coffee is what you are looking for. Although darker roasts are less acidic and contain the least caffeine, they are the boldest in their flavor. Often, these darker roasts can have a bitter taste to them as well.

Final Thoughts

As you can see, answering the question “What coffee bean makes the strongest coffee?” is not as easy as you may have hoped. Depending on what your definition of “strength” is will change the answer you are seeking.

But if you didn’t know before what the TRUE meaning of strength is when referring to coffee, hopefully now you have a clearer understanding.

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