The truth about coffee freshness

The truth about coffee freshness

When it comes to coffee, freshness is often equated with quality. The common perception is that the fresher the coffee, the better the flavour. But is that always true?

Our head of coffee Jamiel has shared some fascinating insights that challenge this conventional way of thinking, so let’s dive into his thoughts and the science behind coffee roasting.

Head of coffee at Rounton Coffee Jamiel

The literal freshness… just out of the roaster

You might think that the moment coffee beans emerge from the roaster is when they're at their freshest. Technically, that's correct. However, this "freshness" is a bit misleading.

Freshly roasted coffee beans are full of CO2 gas, a byproduct of the roasting process and this gas isn't something you want in your coffee cup. That's why coffee needs to "degas" before it reaches its optimal flavour.

The degassing process: why waiting is key

Degassing is the process where CO2 escapes from the roasted coffee beans. This is why our coffee bags have one-way valves – to allow gas to escape while preventing air from entering. Typically, around 40% of the gas is released in the first 24 hours post-roast, but the process continues days after roasting.

The presence of CO2 can cause the water to flow unevenly through the coffee grounds. This results in an uneven extraction where some parts of the coffee puck are over-extracted (leading to bitterness) while others are under-extracted (resulting in sourness or weak flavours).

Espresso is known for its rich crema, the golden foam layer on top of the shot. Excessive CO2 can inflate the crema, making it overly bubbly and unstable. As the CO2 escapes, the crema can collapse quickly, affecting the texture and mouthfeel of the espresso.

Two Stories espresso

The sweet spot: when to brew your coffee

For the best flavour, we recommend waiting 5-10 days after roasting before brewing your coffee. This waiting period allows most of the CO2 to escape, leaving the coffee beans in a state where the flavours can be extracted more evenly and effectively.

However, the optimal time for coffee freshness can vary depending on the roast type, for instance…
- Light roasts - these beans retain more moisture and may have smaller CO2 pockets, so they might be ready slightly sooner
- Medium roasts - these are somewhere in between, usually hitting their sweet spot around the 5-10-day mark
- Dark roasts - with larger CO2 pockets due to longer roasting times, dark roasts might need a bit more time to degas fully.

Finding your perfect brew time

Coffee is a highly personal experience – every single person has different likes and dislikes. Take our team for example, some like fruity espressos with our Chinese Fuyan or Colombian Yellow Bourbon, while others prefer our dark-roasted coffee beans for espresso, like our Brazilian Dark Roast and Colombian Rich Roast.

While our general recommendation is 5-10 days, we always encourage our customers to experiment, especially those who have purchased our coffee for the first time. Some people might prefer the flavours that emerge at different stages of the degassing process. For example, you might find that a particular coffee tastes best a week after roasting, or even longer.

The science behind the flavour

Understanding coffee freshness also involves a bit of science. During roasting, the coffee beans undergo complex chemical changes. Heat interacts with the coffee's natural compounds, creating new flavours and aromas. As the coffee degasses, these flavours continue to develop and mature.

- Light roasts - these retain more of their original flavours and often have fruity or floral notes
- Medium roasts - these balance the original bean flavours with the richness from roasting, offering a more rounded profile
- Dark roasts - these are dominated by the flavours developed during roasting, often described as bold, rich, or chocolaty.

Coffee fresh out the roaster

Redefining freshness

Freshness in coffee isn't just about how recently the beans were roasted. It's about how well the flavours have developed and how little CO2 remains to interfere with extraction.

In the world of coffee, and particularly espresso, patience truly pays off. Allowing your freshly roasted beans to rest for a few days can significantly affect the quality of your coffee. By understanding and respecting the degassing process, you can achieve a balanced, flavourful, and satisfying coffee that showcases the true potential of your coffee beans.

So, next time you receive a bag of coffee that's a few days past its roast date, know that it's likely at its prime, ready to deliver the best possible cup.

Happy brewing!