One way valves and coffee outgassing

The Importance of Freshness for Coffee Flavour: Understanding Outgassing and One-Way Valves

Great coffee is so much more than just a drink or a caffeine boost; it’s a sensory experience and a little island of indulgence in hectic schedules. One aspect that really influences the quality of this experience is the freshness of the coffee. We understand this at Dreambeans and we want to dig a little deeper into the importance of coffee freshness, the process of outgassing, and the ingenious technology of one-way valves on coffee bags.

The Freshness Factor

The journey of a coffee bean from plant to cup is a complex and delicate progression. Each step builds on the previous one and impacts the taste and aroma of the final coffee. The freshness of the coffee bean plays a pivotal role in establishing the flavour and aroma of your coffee. When coffee is roasted, a clock starts to tick. As soon as the roasted bean is exposed to the air, the amazing (and delicate) volatile compounds that contribute to the flavour of the coffee start to degrade, so it’s important that they are packaged in perfect condition and at just the right time in the outgassing process, more of which below.

The Outgassing Process

A significant part of understanding coffee freshness comes down to a process known as ‘outgassing’ or ‘degassing’. When coffee beans are roasted, they undergo several chemical reactions, one of which produces carbon dioxide (CO2) within the bean. Over time, this CO2 gradually escapes, or ‘outgasses’ from the bean.

Outgassing is most vigorous in the first few hours after roasting but continues to a lesser extent for several days. While it is essential for some of this CO2 to escape before using the coffee (excessive CO2 can interfere with the extraction process), the presence of CO2 within the beans is also crucial for preserving the coffee’s flavour. This is because the CO2 forms a protective layer around the roasted beans in the bag, preventing oxygen, the enemy of freshness, from coming into contact with them.

The Role of One-Way Valves

So, how does this outgassing process help maintain the coffee’s freshness? It’s most;y down to the one-way valve in the coffee bag. Look closely at any high quality coffee packaging. There is a small device built into the packaging of nearly all high-quality coffee brands, including Dreambeans.

The one-way valve allows CO2 to escape from the bag without letting oxygen in. The CO2 being released from the beans creates a positive pressure within the bag, and pushes the oxygen out of the bag through the valve, leaving the coffee beans inside bathed in a blanket of CO2. Now, CO2 is a very inert gas. It does absolutely no harm to the coffee, in fact, it protects it from harm. Without oxygen, no bacteria or mould or anything like that can attack the coffee, leaving it snug in it’s mantle of CO2.

In this way, the one-way valve serves two purposes. It allows the beans to continue outgassing and driving out the oxygen without bursting the bag, and it helps keep the beans fresh by preventing them from coming into contact with oxygen. Like everything else, there are different grades of one-way valves on the market. We use very high quality, high performance one-way valves, and we can ensure that the coffee beans you buy from Dreambeans are as fresh and amazing as they were when they left the roaster.

This is why an unopened bag of beans will last in perfect condition for a relatively long period of time.