The freshness of roasted coffee beans directly impacts the quality of the end cup. The best cup coming from coffee beans that aren’t too fresh but haven’t yet turned stale. Sounds complicated, but most specialty roasters will pop a roast date on the bag, rather than a best before, to give you a hand.

The general rule: Aim to brew with beans that have been rested for a week from roast, and are less than 6 weeks old, where they will begin to stale. As we dig deeper, we might find a few little tricks to extend this ideal lifespan.

When coffee is roasted, it produces CO2. Depending on how dark the result, coffee can produce different amounts during the roast. Darker coffee giving off more CO2 during roast. Not only is CO2 produced during roast, but it is also contained within the roasted coffee and releases post-roast. Not surprisingly, the darker the roast, the easier it is for CO2 to release, when compared to lighter, and therefore denser coffee beans.

For the first 24 hours after roast and continuing at a declining rate, over the first week, coffee will degas CO2. In fact, after the first week the coffee will have lost about 60% of its CO2.

High CO2 in coffee can make brewing a little tricky. Brewing while coffee is fresh can be unpredictable and hard to repeat. Super fresh coffee can also have a taste of carbonic acid, or sharpness to it that can overpower the aftertaste. It will often be harder to push for higher sweeter extractions.

As coffee is exposed to air over time, it will begin to stale. Losing aroma, and vibrancy in the cup as it stales. This will result in a muted cup of coffee, that can be bland and lacking any vibrancy.

"Most coffees sold in the supermarket have a best before date. This is useless as it doesn’t help us know the band (after 1 week, up to ~6weeks), when it will be ideal. We need a roast date! "

It is generally understood that darker roasts will be able to be used slightly fresher, and will stale slightly faster, however with the way we roast coffee (not too dark), I’d suggest the >1-<6 week band. 

Fresh coffee has some CO2 in it. For a long time, the amount of crema, or a bubbly bloom, meant you had fresh coffee. However, with lighter roasts sometimes very little crema is produced in espresso, and sometimes the bloom is less impressive. The best way to assess freshness, alongside the printed roast date is to taste and smell.  

Coffee that is too fresh may taste sharp and lack sweetness but will have plenty of aroma as ground coffee. Stale coffee will often lack aroma as ground coffee and will taste empty, bland and sometimes bitter. When your coffee has lingering sweetness, matches your tasting notes on the bag, has plenty of aroma as ground coffee, you’ve likely nailed the brew and used coffee that is the right age. 

The best way to store coffee, to preserve and extend the ideal brewing band is to store in a temperature stable environment, dry, outside of direct sunlight, in an airtight container. This will limit the oxidation over time. Grind only what you need for the brew, as whole bean lasts longer. 

Extending freshness 

Yes, you can freeze coffee. This can extend the freshness range well beyond the 6-week mark. The best results come from freezing one serve in a vacuum sealed container. This will limit the chance of condensation impacting your brew, if you were to bring larger volumes of frozen coffee back to temp. You can grind frozen coffee.  

Why don’t we do this at our café? We love tasting fresh coffee, in season, and think there are too many coffees delicious to taste each season, let alone if we were to store them. 

Freshness in whole bean vs ground coffee. 

Grind what you need for each brew. Ground coffee has a lot of surface area to oxidise and will begin to stale much faster, outside a container, it won’t last a day. This is why the best purchase, above all other brew equipment, is a burr grinder.  

What if it’s outside the range? 

No need to worry if your coffee is slightly out of the peak usage range of 1-6 weeks. There are a few tips for using our coffee outside this ideal time frame.  

If you have slightly fresh coffee under a week old there are a few things to try if your brew is tasting sharp or is under extracting. When brewing espresso with fresh coffee, try dosing down slightly. Start with 0.5g less than the recommended dose. For fresh filter coffee, a few days from roast, I usually maintain the ratio of 15g – 250g brew water, but grind slightly finer. 

When using older coffee, that is tasting empty, stale or dry due to age, I like to dose up. I dose up 0.5g as a start for both espresso and filter. This can help bring a bit more vibrancy to the cup. 

What do they do in a café? 

The best cafes will cycle through product available for retail, giving customer the opportunity to buy fresh beans for home. There is little waste, as the beans that are for sale on the shelf for the first week, will end up in the hopper for the second and third week, cycling through and eliminating the opportunity for coffee to stale. 

Buying coffee from your local café is the best way to find whole beans that are in their peak. Get some advice from the barista about brewing with them, they’re the expert, and what you should get, for the way you’re brewing. The supermarket stuff has likely been there for ages, and ain’t nobody going to help you there. This is another way you can level up your home coffee.