A new bag of coffee beans from the supermarket doesn’t guarantee freshness. One common mistake that most of us make is checking the expiry date and overlooking the roasting date; it’s the one detail that makes the difference between a perfect cup of coffee and one that falls flat.
What’s so important about checking the roasting date? Do coffee beans freshly retrieved directly from the roaster have the best aroma and taste? We find out.
What happens during the roasting process?
During the roasting process, carbon dioxide is one of the major gases that form within the bean. This is due to the heat that catalyses chemical reactions, breaking down the complex carbohydrates into smaller molecules which causes browning of the beans.
As the roasting continues, carbon dioxide is slowly released during a crucial process known as degassing.
What happens after roasting?
Shortly after roasting stops, degassing is accelerated and the conversion of sugar happens. But the presence of carbon dioxide in the bean plays a prominent role in the bean’s quality, the coffee extraction, and crema formation.
Every roaster’s challenge is to ensure the beans are degassed for an optimal period. Too soon and the resulting brew will be under-extracted as the gases will obstruct water flow through the grounds.
When the beans are left to degas for too long, they start absorbing oxygen also known as oxidation. This, in turn, will cause the beans to go stale.
When is a good time to brew coffee after the roasting date?
Generally, most roasters recommend waiting three days to a week after the roast date before grounding the beans.
There’s no definite time frame as it depends on multiple factors such as the bean’s variety, roast profile, and brewing method. For instance, darker roasts degas more rapidly than lighter roasts, resulting in shorter waiting time.
The best way to gauge is to purchase your beans from a local roaster or an online subscription service. Often, the beans are sold within a few days of being roasted and are ready for brewing.
How do I ensure my roasted coffee beans are fresh?
All coffee beans are usually packed and sealed tightly to slow down the degassing and oxidation process. But once the bag is opened, the process resumes.
The expiry date on the bag of beans is a false indicator of its freshness. It is best to use the beans within 4-5 weeks of its roasting date before the intensity of its flavour notes and aroma decline over time.
Source: https://theprimadonnalife.com/, unsplash