How to Grind Robusta Coffee Beans
What is robusta coffee?
Robusta coffee is one of two main types of coffee consumed around the world, most of which is produced in Vietnam, the second largest coffee producing country in the world. Over 90% of the coffee grown in Vietnam is exported to other countries. The United States is the third largest importer of Vietnamese coffee behind Germany and Italy.
Despite this, single origin, specialty Vietnamese robusta coffee has never been available in most American stores or coffee shops as much of the imported coffee has traditionally been allocated for instant blends and commercial coffees with no reference to the origin of the beans.
What makes robusta coffee different?
Because of this, robusta coffee can be hard to come by or even surprisingly stronger than a typical cup of coffee when first consumed. Why? Robusta coffee has twice the caffeine content of arabica coffee– the most widely available and consumed coffee in the world and the United States– and it offers a deep, bold flavor with notes of nuts and dark chocolate compared to bright, floral notes of arabica.
In addition to its extra strength, robusta coffee beans differ from their arabica counterparts in terms of their physical composition as well. For starters, the bold robusta bean is much more dense.
Why are robusta coffee beans denser than arabica coffee beans? Robusta coffee has 60% less sugars and fats than arabica does, which results in a denser bean on a molecular level. Fatty oils are essentially what makes a product more “soft.” This hardiness is congruent with the high caffeine content of robusta, and also contributes to its natural pest resistance.
When grinding coffee beans at home, this density found in robusta coffee beans may require extra time to fully grind the beans. Much like with any whole coffee beans, it’s recommended to use a burr grinder with durable blades to make the most of the grind.
How to grind robusta coffee beans
When grinding coffee beans, it’s important to take note of how the machine sounds during the process and what the final grounds look like. They should be uniform in size and the machine should not make louder-than-normal noises. If you find many coffee grounds scattered around the machine after the grinding process, there may be static built up in the machine. To reduce this, you can employ the use of the Ross Droplet Technique, which involves the use of a single drop of water mixed with the whole beans before they’re placed into the grinder.
Another important quality to note is the roast level of the coffee beans– the more roasted they are, the more brittle the coffee beans are. Brittleness affects how easily a coffee bean will grind with darker roasts being ground more easily. During the roasting process, heat evaporates water inside of the green coffee beans and stretches the cell size of the bean, resulting in a final roasted bean that is more easily breakable in a grinder. With roasted robusta beans, density still plays a part in determining how they will grind– in the end, your coffee grinder may require a bit more time to break down these beans.
Ultimately, grinding robusta coffee beans is not inherently different from grinding arabica coffee or other varieties of coffee. They are relatively denser, but by no means impossible to grind so long as you have a functioning coffee grinder. If you encounter issues with grinding robusta coffee beans, we recommend taking a look at the burrs in your grinder while ensuring the chamber is free of debris or buildup as well. With that in mind, you can dial in your grind and your brew for strong, bold Vietnamese coffee!