You wouldn't eat old lettuce, that's been left to rot, so why would you drink old coffee where the beans have been left on the shelf for month maybe even years!
Let's be clear, coffee is nonperishable; meaning that if you want to drink coffee that was roasted a year ago, you can. What will it taste like? Not of much...like a cup of tea [don't tell anyone I said this please]. Once coffee is freshly roasted, the flavour starts to degrade, fading and slowly getting worse. This process is sped up when the coffee is in ground form.
When you grind coffee you release the built up CO2 created during roasting, which acts as a barrier against the oxygen, the element which degrades the coffee. Therefore my number 2 piece of advice to anyone who wants to enjoy tasty coffee is to ensure you buy beans. This way you can enjoy the delights of freshly roasted coffee for longer.
Why am I telling you this?
It's the main reason I got into coffee roasting.
I was shown around a roastery in Nottingham and it was there that I tried my first mouthful of coffee from freshly roasted beans. It wasn't that it was the highest grade bean in the world, or that I had travelled a long distance to capture a perfect moment. It was simply that it was FRESH. I remember how much bolder the taste was, how much more depth the coffee had and how I could actually taste some sweetness. Previously, I thought that sweetness came from sugar!!!
When I'm asked how to best improve your coffee experience at home, the NUMBER 1 piece of advice I give is
Buy FRESH ROASTED coffee.
So what is fresh to me?
For absolute perfection, my opinion is that coffee is best between day 7 and day 21. This is the period in which the coffee has had enough time to degas (release the negative CO2 which creates additional acidity) and also close enough to the roast date that it still retains the depth of flavour. In more general terms, try to consume your coffee within the first 3 months of the roast date.
One finally thing...
Buy your coffee with a roast date on the bag, then you'll know you're enjoying the fresh stuff. Remember all kickback coffee comes fresh to you within 2 weeks of the roast date - buy here