Coffee Freshness and You
When I lead tastings and classes, I inevitably get the following questions: where should I keep my coffee for optimum freshness? In the freezer? What kind of container should I get? How long will ground coffee keep? Whole bean?
As with anything coffee, there are a lot of variables at play when we talk about coffee freshness. Where do you live? What's the season? What container is it in? Is it ground? Even the brew method is important: espresso should be older, in general, than coffee for other brewing methods (like, 7-10 days is considered the sweet spot for espresso, whereas coffee that you want to drip or infusion brew is most intense when consumed between 1 and 7 days after roasting). Individual coffees may vary, and we notice that our hot-air roasters produce coffee that takes a bit longer to off-gas.
Where you get your coffee is an incredibly important factor in whether it's fresh or not. Obviously, buying direct from the roaster is a great way to make sure the coffee you're getting is fresh. Getting your prepared coffee from a cafe or restaurant that uses a local roaster is also a good way to ensure that the coffee they're brewing hasn't been sitting around too long (we put a roast date on every bag of coffee so our business customers so they can monitor freshness and rotate stock. This may not always happen, but the tools are there). If you've ever bought coffee from a supermarket, you've probably had the experience of buying stale coffee from an oily bulk bin (when I think about all the great coffees in the world that have been ruined this way, I want to cry). If you do buy from a supermarket, get your coffee in a sealed foil bag with a valve, if possible. This coffee has been exposed to much less oxygen than that in the bulk bin. A good valve bag, combined with nitrogen-flushing (which we do, but few other small roasters do) will keep coffee in a fairly stable state for 1216 weeks after packaging. It's science!
What can you, the end user, do to ensure that your coffee is fresh once you have it?
◊ Buy only what you will consume within a week or two at a time.
◊ Grind it at home, right before you brew. You don't necessarily need to invest a huge amount of money in this. Coffee that's been hacked to smithereens by a cheap blade grinder is still better than professionally ground coffee that's staling at the speed of light, in my opinion.
◊ Protect your coffee from the evil forces that seek to destroy it: sunlight, heat, moisture, and air.
◊ A dark cupboard is the perfect location to store your coffee. It should stay no warmer than about 72 degrees and will protect your coffee from light without your having to do anything. Don't bother with the fridge or freezer. There are no particular benefits to these storage places and they introduce further negative variables, such as taste/odor (like fish or onions in that enclosed space with your coffee), moisture/condensation, and potential degradation of essential oils.
◊ Store your coffee in an opaque, airtight container. The foil bag it came in, rolled down with the air pushed out and resealed with a rubber band, is an excellent option. I also experimented with a TightVac plastic jar, and was pretty impressed at how coffee performed at two weeks and even thirty days (I wouldn't serve the month-old stuff to a customer, but I would give it to my husband to drink at home and not feel even a tiny bit guilty). If you're storing in a dark place, a mason jar is a fine choice.
◊ If you're storing in a reusable container, clean that container frequently. Ideally, every two weeks or so. Built-up coffee oils that become rancid will make all your expensive, fresh coffee taste rancid, too.
This is a rad chart I made in MS Paint. I should note that I made this with coffee IN FOIL BAGS WITH ONE-WAY VALVES in mind, so it's actually quite generous.
Please add arguments or questions in the comments.