What We Know About Coffee Ageing

Coffee ageing is one of the most misunderstood yet important aspects of coffees journey from roaster to the final brewed cup. Many people think that 'fresh is best', but freshness is complex and understanding how coffee ages can help you brew better tasting coffee. The aim of this article is to provide the most updated and accurate explanation of what coffee ageing actually is, how much attention you should pay to it and what practical steps you can take to preserve quality. We’ll also explore the science of degassing, storage methods and what recent research tells us about consumer perception of aged coffee.

What Coffee Ageing Is?

Ageing in roasted coffee primarily refers to 'staling', the gradual loss of desirable flavour and aroma compounds combined with the formation of undesirable ones. Several mechanisms drive this process:

• Loss of volatile compounds: These are responsible for coffee’s aroma. Once roasted, coffee rapidly loses volatile compuonds especially sulfur containing compounds, which are critical for freshness Buffo & Cardelli-Freire, 2004.
  
• Coffee Oxidation: Exposure to oxygen breaks down lipids and other molecules, leading to rancid or cardboard-like flavours Illy Group, Coffee Staling White Paper.
• Degassing of CO2: Freshly roasted beans release carbon dioxide, which initially protects against oxygen but diminishes over time Ribeiro et al, 2006.

In short coffee ageing is an unavoidable chemical process, but its speed and impact depend heavily on coffee storage conditions (oxygen, temperature, light and humidity).

Why Ageing Coffee Is Important

While it may sound counterintuitive, a small amount of ageing immediately after roasting is actually beneficial. Freshly roasted coffee beans contain high levels of trapped CO2 from the roasting process. If brewed immediately, this CO2 escapes rapidly during extraction, disrupting water flow and producing uneven flavours.

Most roasters allow coffee to “rest” or degas for 1–7 days (depending on roast style) before packaging, to strike a balance between preserving aromatics and avoiding excessive CO2. This step is essential in achieving flavour consistency. Research has shown that degassing behaviour is strongly linked to both roast level and packaging method Ribeiro et al, 2006.

While discussing why roasters choose to rest or degass their coffee we want to point out that EcoBarista have recently released a range of paper coffee bags with a thin membrane. traditionally coffee roasters would have empty coffee into tubs and wait for their coffee to degass before packaging, This new product allows roasters to roast and pack their coffee strait after it's cooled. And by the time it get's to their cafes it's ready to go.

Do Different Roasts Age Differently?

To date, there are no peer-reviewed studies directly comparing staling rates across roast levels. However, based on chemistry, it is reasonable to propose that roast level affects ageing:

• Dark roasts: More porous, with surface oils exposed. This increases contact with oxygen, potentially accelerating oxidation.
• Light roasts: Denser structure, fewer surface oils and often more stable. Theoretically, they may retain aromatic complexity for longer.
• Medium roasts: Likely sit somewhere in between.

⚠️ Important to note: this is theoretical reasoning, not established scientific fact. Until controlled studies are published, any claim that 'light roast stays fresher longer' should be questioned.

Why Storing Ground Coffee Is the Worst Coffee Storage Method

If whole beans degrade steadily over weeks and months, ground coffee degrades much faster. The reason is surface area:

• Grinding exposes a much larger surface area to oxygen and moisture, accelerating oxidation and volatile loss dramatically.
• A comprehensive review on coffee flavour and freshness highlights that volatile compounds in ground coffee dissipate at a significantly higher rate than in whole beans. Buffo & Cardelli-Freire, 2004.

This is why coffee professionals universally recommend grinding only what you need immediately before brewing. Even the best storage container can’t fully protect pre-ground coffee from rapid ageing.

But Is Aged Coffee That Bad?

Interestingly, the impact of ageing on consumer preference may not always be negative. A recent Study tested whether consumers could distinguish between coffee roasted 1 day ago versus 145 days ago.

• 70% of tasters were able to distinguish between fresh and aged coffee (statistically significant).
• However, preference was split: 52.4% preferred the aged coffee, while 47.6% preferred the fresh.

This suggests that while ageing changes coffee’s sensory profile in measurable ways, not all consumers perceive it as worse. Some may actually prefer the softer, less volatile flavours of 'matured' coffee.

So, How Much Attention Should You Pay to Coffee Ageing?

• Coffee ageing is real and measurable: volatile loss, oxidation and degassing all shape how coffee tastes over time.
• Storage matters: oxygen, heat, light and grinding all accelerate ageing. Using airtight, opaque, high-barrier canisters (like the Airscape) can significantly extend coffee’s sensory lifespan.
• Resting matters: letting coffee degas for a few days after roasting improves brew quality.
• Perspective matters: while coffee professionals often pursue peak freshness, consumer preferences vary and 'aged' coffee is not universally disliked.