What is Strength in Coffee?

Strength in coffee is a complicated and confusing subject as it can refer to different things. Are you talking about the strength of caffeine? Strength in taste? Strength in depth of flavour? And those questions could just apply to the coffee beans. How the coffee is brewed can impact all of the above.

Factors that also influence our perception of coffee's strength include the amount of coffee grounds used, the grind size, brewing time, and roast level. Ultimately, strength is subjective and can vary based on personal preference. 


What are the main factors affecting coffee strength?

The most common are roast level, grind size, brew method, and caffeine. Allow me to break down how these can influence your perception of coffee's strength.


Roast Level

This is likely how most people consider strength in coffee and is generally what is implied by a " 1-5 strength rating." Essentially, the darker a coffee is roasted, the more intense the taste. But the more intense the taste, the less complex the flavour (taste and flavour aren't the same thing). So, a dark roast coffee will have a big, roasty, sometimes bitter taste, but not in an unpleasant way. Light roast coffees retain all the strong, complex flavours of origin and highlight how the coffees are processed. Medium roasts can bring the best of both. 

  • Dark Roast: Our multi-award-winning FiXX Cubano is an excellent example of a good dark roast. The sweet vanilla flavour shines through the big, exotic, dark roast notes.
  • Medium Roast: FiXX Lisbon is one of our award-winning medium roast coffees. It is a naturally processed coffee that works brilliantly as an Espresso while still having a great depth of flavour for filter coffee.
  • Light Roast: All of our FiXX Single Origins are light roasts which help to highlight the unique flavour profiles showcased by the origins and processes used.


Caffeine and Coffee Species

All of our FiXX coffees are 100% Arabica. Although there are many varieties of Arabica, caffeine is generally stable across all of them. Arabica is one of two major species of coffee plant, with the other being Robusta, which makes up approximately 30% of coffee consumed globally (you can read more about these plants here). Robusta coffee beans are smaller and rounder than Arabica beans, with a higher caffeine content and a more robust bitter taste (hence the name). Because of this, Robusta is primarily used in instant coffee and many blends. So, if you think about strength in terms of caffeine, robusta coffees would be stronger.  


Extraction and Ratio

If you want to get nerdy, "strength" can refer to the concentration of coffee solids dissolved in water, typically measured by the ratio of coffee grounds to water used during brewing. A stronger coffee has a higher ratio of coffee to water, resulting in a more intense flavour and potentially higher caffeine content. Every time you make a coffee, you try to extract the perfect amount of flavour from your coffee regardless of what equipment you use. If the ratio or grind size (more on that later) is incorrect, you will over or under-extract your coffee. And this will have a big impact on your perception of the strength of the brewed coffee. 

Under Extraction

This is when you have not extracted enough flavour from your ground coffee. If your coffee tastes sharp, sour, or overly acidic, it could indicate under-extraction. Under-extracted coffee might lack depth and complexity in its flavour profile, resulting in a weak or thin taste.

Over Extraction

This is when you have extracted too much flavour from your coffee. Over-extracted coffee often tastes excessively strong, bitter, harsh, or astringent. It occurs when too many compounds have been extracted from the grounds. 


Grind Size

Grind size refers to the coarseness or fineness of ground coffee. Getting it right is one of the most critical elements in making a delicious cup of coffee. Different brewing methods require different grind sizes, which, if not used correctly, can lead to over- or under-extracted coffee. You can read more about grind size in this helpful blog, which discusses the importance of grind size and how you can master it.


Brewing methods

How you brew your coffee can greatly impact your perception of strength. Use the same beans to brew an Espresso and a filter coffee, and you'll understand what I'm getting at. When it comes to brewing, any method will generally fall into one of two categories; immersion or percolation. 

Immersion: In immersion brewing, coffee grounds are fully submerged in water for an extended period, allowing them to steep and extract flavour. During steeping, the water absorbs the soluble compounds from the coffee grounds, resulting in a rich and full-bodied cup of coffee. After steeping, the coffee is usually separated from the ground through filtration or pressing. Examples of immersion brewers are...

Percolation: Percolation brewing involves passing water through a bed of coffee grounds, allowing the water to extract flavour as it flows through. In percolation brewing, water is typically poured or dripped over the coffee grounds, and gravity or pressure forces the water to pass through the grounds and into a container below. As the water flows through the grounds, it picks up soluble compounds, resulting in a flavorful and aromatic cup of coffee. Examples of percolation brewers are...


As you can see from the different brewers in different categories, each method, i.e., French press and espresso, can produce full-bodied, intense coffees. Sometimes, knowing which brewer is the best for you is hard! Luckily, we wrote this handy blog to help you decide.


In Conclusion 

Like most things related to strength in coffee, the answers are confusing and ultimately subjective. If you enjoy your favourite FiXX however you brew it, you've made a nice strong coffee. You can read more about this complex question in this FiXX blog post about strength