What are some key points to store coffee to preserve freshness?
Different methods for whole beans vs ground?
You definitely want to keep beans whole as long as possible. Ideally, grind just the amount you need right before you brew the coffee. Keep the whole beans airtight, and freezing probably isn't necessary unless you buy a month of beans in advance.
Use freshly ground coffee. Think of coffee as fresh produce. The enemies of coffee are oxygen, light, heat, and moisture. To keep coffee fresh, store it in an opaque, airtight container at room temperature. Storing coffee in the refrigerator or freezer for daily use can damage the coffee as warm, moist air condenses to the beans whenever the container is opened. Whole bean coffee stays fresh longer because there is less surface area exposed to oxygen. For the best results, coffee should be ground just before brewing and used or stored immediately.
So if you do use the freezer be sure to allow the beens to return to room temperature before opening the bag.
With ground I have found the best way to keep it fresh is to store it in an air tight container, then keep it either in the fridge or in a cool dry place. Avoid any sort of moisture is the key thing I find.
As others have said, keep them whole if you can. This will keep them the freshest. The other main comments here and typical advise, is to keep them airtight and in the freezer. The truth behind this is that it does work, and it all has to do with moisture. Keeping moisture out will prevent them from breaking down. The freezer happens to be a dry place, so it works. Airtight the same thing. In the winter in a dry home, they will be fine too.
Another good tip for whole coffee is to grind them using a burr grinder. Using a cheap blade based grinder will produce a lot of dust, that will make you coffee bitter. We recently switched from a $20 blade grinder to a $50 burr grinder and it makes a world of difference.
Sweet Maria's, my principal vendor, has a page dedicated to this very topic. Basically: store roasted beans air-tight at room temperature. If you're roasting them yourself, don't seal the container until 8-24 hours after roasting.
Don't store ground coffee at all if you can avoid it. It goes stale very quickly.
The best way to store roast coffee beans is NOT in the freezer. The freezer will damage the beans when condensation forms. The oils will break down, and you'll lose some of the flavour. Also, opening your freezer regularly, anything that will cause your beans to fluctuate in temperature enough for ice crystals to form will damage it.
The best place to keep coffee beans is in a air-tight, opaque container. Buy in smaller quantities if possible.
If you absolutely must store coffee for long time in the freezer, there is one way that you could minimize any damage. I would probably take the original, unopened bags of coffee, put them in multiple layers of ziplock bags, removing as much air from each layer and freezing the bags whole. When you are ready to consume it, take one bag out and transfer to your air-tight, opaque container, to be consumed in the next few weeks. In short, freeze and thaw at most once. Light, air, moisture are bad for coffee.
The fridge would be the worse possible place to store it. Coffee should never go in the fridge.
I place the bag of beans in the freezer. I have been told that this keeps the oils from escaping.
Whole beans keep much much better than ground. It's not necessary to keep the beans in the freezer, as long as they're in a pretty air-tight container, they're fine at room temperature.
Simple and to the point.
Think of coffee as bread, after 7 days is not good anymore.
When storing roasted coffee beans you're wanting to keep it away from four things:
Additionally, the first few days after the beans are roasted they are emitting CO2 gas, which is why many coffee packages have a one-way valve on them to they don't pop.
I use resealable bags (zip-lock) with the one-way valves on them, and store them in the pantry. You can squeeze most of the air out of them as you seal them back up again. I get the bags from a local roaster. Use several smaller bags (about 250g) instead of one big bag. This is good for two to three weeks.
I'm not a fan of storing in the fridge or freezer as the cold and fluctuations in temperature every time you take the bag out will cause condensation.
The reason I think the bags are superior to an airtight container is because you can get most of the air out of the bag, whereas with the container whatever space isn't taken up with beans is taken up with air. (Maybe store the bag in a container if you're a fan of overkill.)
If you need to store your beans for longer than three weeks, bag as above, then in a couple of zip-lock bags and put them in the freezer. Take each bag out and put it in the pantry as you start using it.
Only store whole beans and grind them as you use them. If you are storing pre-ground, it is already going stale.
I keep whole beans in mason jars and vacuum seal them. They sell an attachment that works with my foodsaver. It keeps them fresh for months in on the shelf in the cellar.
Supposedly coffee beans kept in the freezer can absorb some of the flavor of whatever else you might be keeping in the freezer. I don't know if this is true, but it's something to keep in mind.
I've always been told that storing coffee beans in the freezer is a no-no.
Also, storing coffee beans in an airtight container might not be a good idea, as the beans release gas as they mature, which could cause the container to break (this is why the bags from Starbucks and similar places have escape valves).
The rules I've heard the most from my local baristas are to avoid temperature changes, to keep it in the dark and to just buy enough for 2-3 weeks.
I keep my pre-ground beans in the freezer in their original packaging (to re-close, I use tape or the bend-ends tie they came with). I do not defrost them before grinding.
I don't have any particularly good reason for keeping the beans in the freezer; it's just how my parents did it, so I do it too.