Fresh is best? Not always. We come bearing good news – we can all relax a little.

Hey, folks, good news, you don’t have to stress about stale coffee. At least, not as much; not when it’s a light roast.

There have been rumblings over the last few months that have been growing around challenging this dogma: Fresh or bust.

When I started working as a barista many years ago (yeah 2005!) there were a lot of stressed-out people. That unease manifested in rifling through the retail coffee shelf in the local cafe. If you were a typical human at the time, you’d be hunting for the holy grail – 5 DAYS off roast! Nothing older would do. ‘Any older and the flavour will begin to degenerate!’ you’d groan. Honestly, there was merit to all that fuss. At that time (and even now) there are loads of folks/ brands/ roasters who steer towards team darker roast – Development at all cost.

Now, this letter isn’t about passing judgment to how light or dark you like your coffee – But I will say, in a Light Roast VS Dark Roast Street Fighter match, you’d see some serious endurance points on team Light Roast.

What is this sorcery?

Let’s start at the very beginning – the birth of a batch of freshly roasted coffee. Once the seeds hit the inside of the rotating drum, as they’re tossed they lose their remaining water weight, turn yellow, turn brown, change from a glass-like state to an expanded rubber-like state at the cellular level (first crack) and by the time that happens, for us anyway, the coffee is already out of the roaster and in the cooling tray.

The main reaction that’s happening during that time is the Maillard Reaction. The same one that happens when you brown onions or bake bread. It’s the secret sauce of life. Everything is more delicious when that relay race of amino acids and reducing sugars does its thing. We’re better with it around.

(On that note, if you’d like a rabbit hole to go down this morning, here is the study that helped inform this letter).

Trapped gas and keeping things comfortable

A byproduct of this browning reaction is, well, trapped gas 💨.

It means the right reactions happened, but the degree of which that gas is trapped wholly depends on the degree to which the coffee is roasted. Light roast = more tightly trapped gas. Dark roast = more readily available gas. Releasing that gas happens with air, over time. The gas release also happens when water hits it – Like when hot water from your kettle first hits the ground coffee in your V60 or Aeropress, or your chosen brewing method.

Humour me for a second – Think back to the first time you brewed a lighter coffee. Were you surprised at the lack of vigorous bloom (bubbling gas activity) compared to the amount of active bubbling a darker or more developed coffee would supply? Think of the bloom in darker roast as more of a boom-bust kind of thing – SO gassy! Then when you went to brew a cup a few days later, things then appeared significantly more under control.

In a light roast, it’s a different world.

What does this mean though? Well, you might find a very light coffee will still have good bloom activity even months after it was roasted. That bloom activity seems relatively similar at day 3 off roast and day 18. That trapped gas leaving the coffee at a much slower rate means you might not be tasting the full potential of that coffee until at least a month off roast (Yeah. Nuts, right?). It also means there is no longer a need to freak out about having too much coffee in the cupboard or that if you’ve got a 3-month-old bag of something delightful, it’s definitely not past its prime. It may be the best its ever tasted.

“In a Light Roast VS Dark Roast Street Fighter match, you’d see some serious endurance points on team Light Roast.”

Does this mean light roast coffee is immortal or something? Well, no not exactly (though if you have something you’d love to keep in a time capsule, a good vacuum sealer, and freezer setup is great for that). After that extra gas is long gone, you’ll start to taste the flavour fade gradually, 6 months or more, those bright and clear flavours you initially fell in love with leisurely ride on into the sunset.

There’s a caveat to all this – This idea doesn’t seem to apply to darker coffee. Who knows, maybe this is a way to gently nudge your friend to enjoy lighter brighter things? Or if not, at the very least you have a secret superpower now – The nirvana of nursing that bag you enjoy, knowing it will only get better with time.

So, grab your brewing device of choice, make a cup of something delightful this morning. Be humbly smug as you lift your cup because you now know a pretty key secret of a stress-free coffee experience.