Degassing, or “resting” coffee after roasting is necessary to get the most flavour out of your coffee. When roasting your own coffee beans at home, the chemical reaction that causes the coffee to brown can produce quite a lot of carbon dioxide, most of which stays trapped inside the freshly roasted beans. The majority of this gas leaves the roasted coffee within the first 3-6 days after roasting.

The gas can build up in a container, which is why commercial roasters will use a one way valve on their bags. A one-way valve is not necessary to degas your coffee at home.

So, why can’t you immediately start brewing coffee after roasting it?

Degassing espresso coffee

When you brew espresso, it’s a process that uses quite a lot of pressure.There are additional variables like grind size, and temperature of water that can cause a lack of flavour, or a bad extraction if the coffee is not rested enough. You ideally want to leave it for four to six days before brewing for espresso, even longer if possible. In experimenting with degassing, we found that optimum flavour is anywhere between 10-14 days. But we know it can be hard to wait that long.

Degassing filter coffee

Filter coffee has a lot more leeway for resting. We recommend resting filter coffee for three to four days before brewing, as you may notice some green “vegetable” or “grassy” flavour notes coming through to the cup of unrested coffee.

Degassing summary

Degassing or resting coffee before brewing is important.

But either way, it’s really worth leaving your freshly roasted coffee for at least 12 hours before brewing.

But here’s the thing: you can try it for yourself! Brew a few batches a few hours or days apart, and then taste them all at the same time. That’s one of the real advantages you get of roasting your own beans at home.

An incorrect or insufficient storage container can result in premature staling of coffee. Air and moisture getting into the container can accelerate the process.

Stale coffee tastes flat and woody, with notes of cardboard, all of which are unpleasant in your morning brew.

Interestingly, darker roast coffee tends to go stale faster than lighter roasts. Darker roasts are more porous, making it very easy for air and moisture to get into the beans and create havoc on their flavour.

So, here’s what to do to keep your coffee its freshest while resting and degassing:

Keep it airtight, and keep it dry

Pop it in a resealable bag, even better if it has a one-way valve to aid in degassing. Otherwise, keep it in an airtight food container, or, even better, a dedicated coffee storage container.

Keep your beans in the dark

You can think of your freshly roasted coffee beans as being nocturnal, they love the dark. Light, and sunlight in particular, speeds up the staling process.

Don’t put it in the fridge (or freezer)

Coffee shouldn’t go in the fridge, although it seems to be a pretty common thing. Ground coffee is a natural deodoriser, meaning that it will absorb the aromas around it. So yes, if you would like your coffee to taste of your leftovers, keep it in the fridge. Additionally, any condensation that may form in the inside of your coffee storage container will spoil your coffee.

Freezing coffee is an option, but really is only needed if you have a large amount of coffee you want to preserve. When you’re roasting your own coffee, that’s really not needed. Anticipate your weekly coffee needs and roast as much as you will need, on demand.

For now, we’re going to assume that you already brew coffee at home. When tasting and evaluating coffees, we recommend sticking to the brewing method that you already know and are confident in.

Right now, all that you need is a few different coffees, a notebook, and some time to get seriously buzzed on caffeine!

1: Compare two or more very different coffees or roasts

Having a frame of reference is imperative in comparing your roasted coffees. You can either taste test multiple roasts of the same coffee from several roasting sessions, or taste completely different coffees in the same tasting session.

2: Brew the coffee the same way

Use your existing favourite way of brewing coffee. Make a point of brewing the coffees in exactly the same way.

3: Cool it down

Have you ever noticed that very cheap beer tastes better when it is ice cold? Or that very bad coffee tastes better the hotter that it is? You are able to pick up more flavours the closer the coffee is to your body temperature. We can recommend 50-65˚C if you want to be specific; Warm, not hot, to the touch also works.

4: Focus on feel first

Think about the texture of the coffee. Is it heavy? Does it feel like it coats your mouth? Does the flavour linger for a long time? Grab your notebook and start writing it down.

5: Describe the taste in your own words

Forget all the fancy descriptions that you find on coffee packages. If you taste apples, that’s fine. If it reminds you of blueberry crumble...sounds good! Write it all down to record everything you taste.

6: See how it compares to the label

Now that you have had your own tasting experience, compare what you have written to what’s on the label. Hopefully, you will notice some similarities. Keep repeating the process of tasting coffees; The more coffees and roasts that you taste, the more confident you will become in your descriptors.