Is Robusta Coffee Bitter?

Every morning, millions of people enjoy a cup of coffee as a way to kick start their day and prepare for work. However, an overly bitter cup can leave a bad taste in your mouth and, more often than not, this unpleasant flavor is due to the use of Robusta beans in your brew. 

Robusta coffee is far more bitter than other varieties due to a number of genetic characteristics. While bitterness is an essential flavor profile in all coffee, Robusta beans can often be overpowering in this respect, making them more appropriate for coffee blends.

In the rest of this article we will examine all things Robusta. We will explain what makes Robusta beans so bitter and some of the different ways you can reduce this unpleasant taste. We will also examine the vital role of Robusta beans in the global coffee market as well as their history in the Italian art of espresso.

Why Is Robusta Bitter?

One reason for Robusta’s bitter taste is the higher proportion of caffeine that these beans contain. Each Robusta bean is about 2.7% caffeine compared to Arabica beans’ caffeine, representing 1.5% of each bean’s mass. Robusta species are also high in chlorogenic acid, which contributes to their bitter taste.

High caffeine content and the presence of pyrazine leads to the bitterness that characterizes Robusta coffee.

How to Reduce Bitterness in Robusta Coffee

Now that we understand why Robusta beans make for a more bitter brew than Arabica varieties, it is important to look at the other factors that make your coffee taste overly bitter and how we can mitigate them to help you brew a more delectable cup of coffee.

Steeping Time

The extraction process that turns your hot water into delicious coffee is a time-sensitive affair. Allowing your coffee to steep too long will cause your coffee, regardless of the species, to be overly bitter.

The first step to producing delicious coffee is understanding how long to let it steep as this changes for different brewing processes. Using a drip system, the steeping time should be around 5 minutes. A french press process, on the other hand, requires only 2 minutes. When using an espresso machine, only 20-30 seconds are required to properly brew a cup. 

Once you have your time dialed in, set an alarm so that you know exactly when to pour your coffee. 

Grind Size

When coffee is ground, it creates more surface area that allows flavor compounds to be extracted. A grind that is too fine can often cause more bitter elements to come to the front of the flavor profile. 

To reduce the bitterness in your brew, use a coarser grind. Keep in mind that different brewing methods require specific grinds, so do your best to find a balance between flavor and your preferred brewing method.

Water Temperature

The ideal temperature for coffee extraction is between 195˚F and 205˚F (91°C to 96°C). If your water is too hot, you run the risk of extracting the bitter compounds and ending up with a less than perfect cup of coffee. 

A good trick to keep yourself from using water that is too hot, is to get in the habit of letting your water sit for a few minutes after it has finished boiling. This way, you are far less likely to end up with a  bitter cup.

Dirty Equipment

Another common problem that can lead to overly bitter coffee is dirty equipment. Over time, residue builds up in coffee machines, and the bitter compounds can be particularly noticeable in a cup of coffee. 

To prevent the bitterness that comes from using dirty equipment, make sure you rinse out your gear with hot water after every use. Rinsing your equipment before the next use as well is even better.

Milk, Sugar or Salt

Adding a bit of milk or sugar is a time tested cure for a bitter cup of coffee. However, only a few people know how a pinch of salt can affect the flavor of your coffee. 

While sugar simply masks bitterness, salt actually neutralizes it. Sodium ions react with your taste buds and prevent you from tasting the bitterness, but be careful not to add too much salt or you will be left with a briny and undrinkable cup.

Why Grow Robusta Coffee?

If Robusta coffee is so bitter, why does anyone grow these plants in the first place?

There are several reasons why Robusta beans are grown around the world despite Arabica’s overwhelming popularity among coffee drinkers.

  • Higher Yields. Robusta varieties consistently outperform Arabic species in terms of total bean yields from similar-sized crops. 
  • Heartier. One of the most appealing characteristics of Robusta plants is their resilience. This fortitude makes them a popular choice for farmers around the world since there is less risk of crop failure from various causes than Arabica species. 
  • Caffeine. The same caffeine that is partly responsible for Robusta coffee’s bitter taste is also why it is favored. Coffee is a pick-me-up after all, so higher caffeine is a favorable quality that continues to make Robusta a useful crop.

What Are Robusta Beans Used For?

With so many coffee aficionados obsessed with the sweet and complex flavors of Arabica beans, where does Robusta coffee fit into the picture?

The most common use of Robusta is instant coffee. Through a couple of different processes–either freeze-drying or spray-drying–Robusta beans and their prized caffeine, are transformed into powdered granules and sold in jars around the world. 

The emphasis on caffeine content over flavor profile that typifies instant coffee makes this the perfect use for Robusta beans. This popular beverage accounts for a large portion of the world’s production of these coffee varieties.

The rest of the world’s Robusta beans are dedicated to blended coffee. Blends refer to the practice of mixing beans from different sources into a single roast. Coffee producers do this for many reasons, such as reducing price, managing different bean sources, and producing more complex flavor profiles.

However, when it comes to Robusta beans in blends, they are most often utilized to increase the overall caffeine content, making a stronger cup than the Arabic variety would produce.

Robusta and Espresso

While the modern world of coffee is obsessed with the smooth, fruity flavors of Arabica beans, there is a tradition of Italian espresso incorporating Robusta beans in their blends.

Most espresso is produced with a blend of 80-85% of Arabica and 10-15% of Robusta. The use of Robusta beans in espresso blends is a way to increase the caffeine content of these highly concentrated cups of coffee and to create more complex flavor profiles as the two beans interact.  

An essential characteristic of any good cup of espresso is the cream or froth produced through the high-pressure brewing process. Many baristas believe that the oil content of Robusta beans improves an espresso’s crema, providing another motivation behind the blended roasts utilized in this Italian approach to coffee.


There is no doubt that Robusta beans produce coffee that is more bitter than Arabica varieties. However, the perfect cup of coffee depends on the person drinking it. Many people prefer the earthier tones and extra kick that comes from these hearty coffee plants especially when used in instant coffee and espresso.

Like many things in life, balance is important. The quest for a perfect cup of coffee accounts for the growing popularity of blends that work to fuse the best qualities of Robusta and Arabica beans into a single brew.


Charlie McFarlane

Specialty Coffee Enthusiast. Hungry for knowledge in the art and science behind specialty coffee and decided to document my journey, while sharing it with the public. More than 10 baristas were interviewed; over 21 farms were visited across 5 countries. Almost 100 Coffee Shops. Bean of choice: Pacamara. Preferred coffee country: Panama. Preferred Brewing Method: Aeropress. Facebook | Instagram | Twitter

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