In our previous discussion, we have set our definition on ‘freshness’, discuss what contributes, and briefly mention how coffee can become stale overtime. Clearly, the taste of coffee behaves similarly to an ever-changing living organism. There are periods in coffee flavor’s life, from the moment it is just roasted, progressed into prime and eventually digress and stale. This second article is written to discuss just that, we will delve deeper into the importance of the roasting date, the degassing phase, the ‘prime’ time of the coffee, and the eventual decline.
The Importance of Roasting Date
The roasting date provides crucial information towards the state of ‘freshness’ in the coffee you are buying. Roasting process produces volatile organic compounds (VOCs), whose concentration directly correlates with the degree of freshness in coffee. All you need now is to understand how the coffee taste changes overtime; and you can start using this date as your quality-compass in making educated guess on the state of the coffee’s ‘freshness’ upon purchase.
If the concentration of aromatic compound is highest when the coffee is just roasted, am I implying that the fresh-from-the-roaster-coffee tastes the best? Not really. Why? Because the Maillard Reaction does not only create the volatile organic compounds during roasting, it also produces meaningful concentration of carbon dioxide (CO2), as the byproducts, which needs to be taken into account. That’s why we need to understand the degassing phase.
The Degassing Phase (Resting Phase)
Although around 90% of the CO2 produced were released into the air during roasting, 10% are still trapped inside the coffee beans. You can see how much CO2 gas trapped inside by mixing the just-roasted coffee grounds with hot water. The blooming will be much stronger than usual. The popular Indonesian street-coffee of Kopi Mumbul serves as a fine illustration of this. While the gas itself doesn’t contributes significantly toward the taste, the bloom does proven disruptive in the consistency coffee extraction, particularly in espresso machine.
Thankfully, the trapped CO2 will slowly diffuse out of the bean in the process called degassing. This process will last for approximately 7-days, though we noticed that it is most aggressive in the first three. Thus, we recommend ‘resting’ your coffee for (at least) 3-days before brewing them (7-days for espresso use). In short, just wait until your coffee enters its prime.
Degassing is the reason why coffee packaging features a one-way valve. It allows the CO2 to escape, preventing the packaging ‘blow-up’ during shipping.
The ‘Prime’
When your coffee finishes degassing, it enters its peak ‘freshness’ when it tastes the best. Even though the concentration of VOCs isn’t as high as the just-roasted one, the drop is not significant compared to the increase in extraction-efficiency obtained by degassing enough CO2. It’s a small investment for a huge gain in flavor.
Depending on how you store your coffee, the prime period usually ranging from couple-weeks to 3-months, before it gradually (and inevitably) start declining as it becomes stale.
The Expiry Date: A Misnomer?
In short, consume your coffee when it’s prime, or 10-days to 3-months after the roasting date. But then again, why does the expiry date labeled 1-2 years from the roasting date? Unlike perishable food items, coffee doesn’t exactly ‘expire’, but it does go stale. As we learned in the first part of this series, staling is the process where coffee loses its aromatic compounds and develops less desirable flavors. So, while coffee won’t make you sick within its ‘expiry’ date, it certainly won’t taste its best.
Please note that I am not advocating you to avoid all grocery-store coffee nor buying only from your local specialty coffee roaster. What this article advocates is better consumer awareness, that it is possible to have better quality coffee for your morning routines by predicting its prime through its roasting date.
How you store your coffee is important in prolonging the prime-ness of your coffee, as oxygen and moisture play huge role in the stalling process. In the next and final part of this series, we will explore the best practices for coffee packaging and storage to maintain its freshness. So stay tuned!
