Why We Don't Print a Roast Date in Days

Why we don't print a roast date in days

A soft hiss as you open the bag – and the aroma rises at once, dense and warm, before you even know what day it was roasted.

What you smell in that moment is more than a preview. Taste and smell are inseparably linked – much of what we experience as aroma only forms once you swallow, through retronasal olfaction. But already now, at the open bag, your brain releases dopamine simply because you know what's coming. Anticipation is part of the enjoyment, not just the first sip.

Pour the first hot water over freshly ground beans shortly after, and the coffee in the filter lifts like a small breath, domes, crackles softly. This bloom is no accident and no disruption in the process. It's gas finding its way out – and that same gas is exactly why we don't print a roast date in days on our bags.

Why roasting produces gas in the first place

Roasting is much more than beans simply turning brown. In the heat, hundreds of chemical reactions happen at once, the very same ones that create caramel, chocolate and nutty notes. As a by-product of exactly these reactions, carbon dioxide forms, trapped in the bean's cell structure and only slowly released. The Specialty Coffee Association describes this process in its scientific column «Coffee, Decoded» by Peter Giuliano, its Senior Advisor for Scientific Communication: most of the CO2 escapes quickly within the first 20 days after roasting, after which the process slows down noticeably – and this same CO2 is also what gives espresso its rich crema and creates the bloom in filter coffee we described above.

As long as CO2 is escaping, it also keeps oxygen away from the bean – a kind of natural shield. How much of it leaves on the very first day depends heavily on roast level, bean and packaging. This spot used to say «a large part within the first 24 hours» – we couldn't back that figure up in the literature, so we removed it. What remains is the Specialty Coffee Association's description from above: most of the CO2 leaves within roughly the first 20 days, after which the process slows down noticeably. Only once most of the gas is gone does the bean really start to age – and ageing here means that hundreds of volatile aroma compounds change, each at its own pace, some faster, some slower. The literature doesn't agree on exactly how many there are: depending on the analytical method and how they're counted, figures range from around 800 to more than 1000 volatile compounds. There's no exact number, and it wouldn't help you anyway – what matters is that there are a great many. That's exactly what makes freshness a process rather than a switch that flips.

Why a roast date in days is the wrong question

A printed roast date suggests a kind of expiry clock: day one, day two, and eventually day X, after which everything is supposedly over. But that's not how degassing works. On our own Roast Level & Freshness Simulator we therefore show the window as a range rather than a number: a typical enjoyment window of roughly 4 to 14 days after roasting, with darker roasts often ready after just 3 to 7 days, while lighter ones tend to need 7 to 14 days. For espresso, the window shifts further out still, with the sweet spot often only arriving in week two to five. These four ranges come from our experience in the roastery and in advising customers – estimated, not measured, and not taken from any study. Brewed too fresh, espresso "gurgles", flows unevenly and often tastes sharper than it could – another effect of the gas still escaping.

No shot is ever exactly like the one before anyway. The bean changes day by day, so does the humidity in the room, and you're not exactly the same person today as you were yesterday. That's not a limitation, that's simply how coffee works. There's no law dictating a fixed day, and nobody enforcing one – just a window in which many things can feel right. It's all complex, no question, but it's not rocket science, and a single date on the bag could never capture this process anyway. It would only fake a precision that doesn't actually exist.

There are still people who'd rather see a fixed number, because a number feels reassuring. That's just as legitimate as choosing a particular machine for the counter that, in the end, says more about a feeling than a measurable difference – nobody needs one or the other, you either want it or you don't. We chose a window instead of a single number because it's more honest to the process. That's our stance, but it's one of many possible ones, and we respect every other decision just as much.

At a glance

What	Typical range
General enjoyment window (all roast levels)	approx. 4–14 days after roasting
Darker roasts	often ready after approx. 3–7 days from roasting
Lighter roasts	more likely approx. 7–14 days from roasting
Espresso, regardless of roast level	Sweet spot often only in week 2 to 5
Main CO2 release after roasting	most of it within roughly the first 20 days, then much slower (Specialty Coffee Association)
Whole beans, outer limit per the Specialty Coffee Association	still reasonably fresh for up to around 3 weeks
Ground coffee per the Specialty Coffee Association	freshness noticeably declines within around an hour

Where these figures come from: The four rows on the enjoyment window are based on experience from our roastery – estimated, not measured. Only the three rows that refer to the Specialty Coffee Association reflect published third-party information.

Who this window matters for

For everyone who already buys their coffee fresh and in small amounts, just as much as for anyone wondering for the first time why two bags from the same day can taste different. For filter and hand-brew fans, whose window often sits at the start of the range, just as much as for espresso people, whose window tends to shift later. You don't need to understand the chemistry behind it to enjoy your coffee – but if you want to know why we chose a window instead of a number, you'll find the answer here, whether you've been with us for years or since this very bag.

How to keep the freshness you've just opened

Once the bag is open, storage plays a big part in how long the window lasts. Airtight, dark and without constant temperature swings – that's exactly how the tins in our Airscape Collection are built. We're the importer of Airscape, and the built-in valve actively pushes air out when you close it, instead of just putting a lid on top.

Just as influential is how shortly before brewing the coffee is ground. Whole beans keep their window open far longer than pre-ground coffee: once the protective surface is broken, CO2 escapes many times faster, which is why the Specialty Coffee Association classifies ground coffee as no longer truly fresh after about an hour. For anyone who wants an affordable, reliable grinder: the VS3 from our Varia Collection or a hand grinder like the C40 from our Comandante Collection. If you want more control over every detail of the grind: the EG-1 from our Weber Workshops Collection. Both price segments make great coffee possible, nobody needs the pricier one, you either want it or you don't.

You'll find our roasts collected in the coffee beans collection – buy coffee beans in Switzerland, conveniently online, whether you're in Zurich, Bern or anywhere else in the country, with delivery Switzerland-wide and to Liechtenstein. If you're still not sure which machine or grinder best suits your everyday routine, our advice tool for coffee machines and grinders offers an honest comparison instead of a sales pitch.

Frequently asked questions about roast date and freshness

Why don't your coffee beans show an exact roast date in days?

Because freshness isn't a fixed day, but a window that opens and closes over the course of degassing. A single date would fake a precision that chemically doesn't exist – we'd rather show the range openly than print a number that, for any individual bag, is only ever partially accurate anyway.

How long does roasted coffee really stay fresh?

As a rough guide, there's an enjoyment window of roughly 4 to 14 days after roasting, depending on roast level and brew method. Darker roasts are often ready after just 3 to 7 days, lighter ones more likely after 7 to 14 days, and espresso often shifts its window even further out, frequently only into week two to five. That's our own sweet-spot range for the best enjoyment, based on experience rather than measurement – as an outer limit, the Specialty Coffee Association also cites a range of up to about three weeks for whole beans, during which coffee is still considered reasonably fresh.

Why does very freshly roasted coffee sometimes taste uneven?

Because there's still a lot of CO2 in the bean. During brewing this gas escapes suddenly, the espresso "gurgles", flows unevenly and often tastes sharper than it would in a few days. That's not a flaw in the bean, but a sign that the roast simply needs a bit more time to rest.

Does the roast level make a difference to how long the beans should rest?

Yes. Darker roasts tend to have a shorter window until they're ready, lighter ones a longer one – you can see both effects interactively in our Roast Level & Freshness Simulator. There's no right or wrong here, just different time windows.

What's the best way to store my coffee beans so they stay fresh longer?

Airtight, dark and at as constant a temperature as possible, ideally as whole beans rather than ground. Tins with a built-in valve, like those in our Airscape Collection, actively push air out when closed and noticeably extend the window compared with a simply rolled-up bag. We haven't measured exactly by how much – that's our observation from day-to-day work.

Can I see your roasts before buying?

Yes, our current roasts are available to experience live in both showrooms, in Bern and Zurich Oerlikon. Online is our primary way of ordering, and the information in this article is enough to buy without a prior conversation.