Coffee Degassing – Meaning in the roasting process
Coffee degassing can affect everything from flavor to brewing. To understand more about elaborate Specialty coffees, we need to understand what degas is and how it can affect the cup of coffee.
What is coffee degassing?
Coffee degassing is the time it takes for air to escape from roasted coffee beans. When you roast coffee, gases – including a lot of carbon dioxide – form inside the beans. This process begins right after the roasting is finished and can last 2-3 weeks. The reason why brewing coffee right after roasting isn’t a good move is because that’s when most of the gas escapes from the coffee.
If you didn’t know, coffee flavor comes from the extraction process, which is when hot water and coffee grounds come into contact with each other. If there are air bubbles coming out that prevent water and coffee from “touching” each other, the coffee will have poor extraction and a lack of flavor.
Coffee degassing is an important process
How is Carbon Dioxide in coffee?
During the roasting process, coffee beans undergo many different chemical reactions. Complex carbohydrates are broken down into smaller molecules, the eggplant will start to turn brown, producing more water vapor and carbon dioxide.
When you first notice the crackling sound, this is indicative of a build-up of gases that exert enough pressure to break apart the cell walls of the eggplant. But gas development continues throughout the roasting process. It is considered an important transformation because it is metabolizing sugar, energy is released and it will produce gas.
However, it can be said that carbon dioxide in coffee beans is not really a negative thing, it even plays an important role. On cited reports from well-known agro-newspapers, they state that “It is an indicator of coffee bean freshness, plays an important role in shelf life and in packaging, affects to the extraction process, which is involved in crema formation and can affect the flavor of the cup of coffee in your hand.”
If you use coffee that hasn’t been degassed for long enough, it may take you longer to brew your desired cup of coffee. Because these gases can help create dramatic looking crema. But the taste will be a bit less than ideal as they have also disrupted the extraction process.
How much time is required for coffee degassing
The general coffee degassing process is 3-5 days to 2 weeks – this is considered the perfect amount of time for the coffee to get rid of the slime. But there is no guaranteed optimal timeline, because it all depends on how it is roasted, grown, processed and how the coffee is brewed. For example, if you’re brewing coffee by steeping or filtering, you can use your beans as quickly as a few days after roasting. This is because the coffee has had more time in contact with the water.
For shot coffee, you are required to let the coffee rest for at least 5 days to a week before using it. Because coffee with the shot brewing method is particularly “sensitive” to the contact time. Shot cup brewing time is much shorter than filtering, so every second of exposure matters. Naturally processed coffee takes longer to degrease than washed coffee. Light roasts also take longer to degrease than dark roasts, which are roasted longer and have more cracks in the beans to allow more air to escape.
How to keep roasted coffee fresh?
How do you know if you’re drinking degassed coffee for the “right time”?
During the first 12 hours after roasting, the internal pressure of the coffee bean is high enough to prevent a significant amount of oxygen from entering its structure. However, after this stage, there is a greater risk of oxidation, which means that oxygen causes the coffee to go stale and lose its aromatic and delicate notes.
If a barrel of coffee contains less than 1% oxygen, the freshness and shelf life of the coffee can be significantly extended. But, imagine what could be the problem with a sealed container of coffee that continues to release CO2 that then cannot escape. This can cause the coffee packaging to break, especially if the coffee needs to be transported long distances between the roaster and the coffee shop or consumer.
Fortunately, there are a number of options available for special roasters that allow the coffee to degrease without the need for oxygen exposure.
The most common option is to mount the degassing valve on the coffee bag. The degassing valve is a one-way vent that lets CO2 out while preventing oxygen from getting inside. This maintains freshness and prevents flavor loss for up to two weeks. It is ideal for roasters who supply coffee in small batches.
Typically, the degassing valve consists of five pieces, including a cap, an elastic disc, an adhesive layer, a polyethylene sheet, and a paper filter. They can be seen from the outside or hidden in layers of packaging.
The Specialty Coffee Association has suggested that if you choose to freeze your beans, make sure to use a truly airtight container and degas as much as you like each time. This is to avoid a build-up of steam on chilled coffee.
When coffee is consumed too quickly after roasting, the aroma is intense but the flavor is not full and often results in an incomplete cup of coffee. On the other hand, when coffee passes the “optimal” CO2 level, the taste of the coffee becomes bland and loses its richness.
For Specialty coffee roasters, it is helpful to provide clear roast and consumption dates to customers, as well as freshness and flavor retention features – such as degassing valves.