I've spent the last several years trying to figure out how to keep my coffee beans fresh for longer than about a week. I love trying different coffees from all over the world, but until recently, I was only able to enjoy them for the first week, and after that, I was stuck drinking bitter, stale, mediocre brew until I ran out.
I'm a compulsive researcher, and Google yielded the same information over and over again: Coffee's enemies are heat, light, moisture, and oxygen.
Heat and light are not something I need to worry about - My house never gets very hot, and my beans are stored inside an internal cabinet (in other words, the cabinet is not built against an external wall), so they are kept in the dark, except when I'm making coffee.
Moisure? Well, I do live in the midwest, in the land of 10,000 lakes, no less (Minnesota actually has 11,842 lakes bigger than 10 acres in size). It is very humid here. However, I think that if I manage to control the O2 exposure, that humidity will also be taken care of (with some exceptions - freezing or refrigerating beans causes condensation on the beans themselves unless you take some extra precautions).
The first thing I learned is to buy whole beans. I figured this one out on my own - I bought some La Minita beans from Caribou Coffee, and brewed an AMAZING cup of coffee. Then my second cup the next day was pretty good. Day three yielded a barely drinkable cup, and from then on, it was bitter and ... not really drinkable. The beans, which I had had ground in the store had gone stale.
Once again, I turned to the internet: ground coffee keeps for a far shorter time than whole beans, because it increases the bean's surface area, and exposes more of the coffee oils to air. Ground coffee's shelf life is about a day. Whole beans in an airtight container last closer to a week. The key is to grind right before brewing.
So.... I bought a grinder (a Kyocera), and began buying whole beans. And that helped enormously. I started out grinding enough beans for my morning cup at home and for my work cup several hours later, and just carried the grounds with me to work. But I noticed that my work cup wasn't nearly so good. So I bought a second grinder (Hario Mini Slim), and started grinding beans right before brewing, at work, too.
This was the number one thing I did to improve the longevity of my beans. My coffee stayed good an entire week instead of a day or two, from this step alone.
Next, I turned my experiments to storage, and refrigeration.
Initially, I tried something called a VacuVin coffee storage container. I love the brand for other things (like wine), but was unimpressed with their coffee storage. First, it didn't seem to prolong the freshness of my coffee. I mean, it's certainly better than nothing, but I didn't find the VacuVin to be better than just leaving the beans in the original valved bags, with a rubber band to keep the air out. And they were unreliable, required a lot of maintenance, and you never knew when it would fail to hold a vacuum.
While I was playing with the VacuVin, I experimented with and/or researched the refrigerator and the freezer. I had kept my coffee beans in the fridge when I was in college, and when I was working at a school in an area a LONG way from the teacher's lounge, I brought in a mini fridge and a coffee maker, and kept my beans in the fridge, then too. But I didn't find that it helped then, so I didn't bother with it this time around. My research suggested that fridge causes beans to go off FASTER - the refrigerator is a very humid place, the dried beans absorb flavors from your food, and the frequent going in and out of the cold causes condensation on the beans themselves.
I did play with the freezer some, with mixed results. Condensation is still a problem, just as it is with the fridge. But I found taking the following steps made the freezer a viable solution, when there is just no other choice:
- Don't take your beans in and out of the freezer. They should go in once, and come out once, never to go back in. Repeated moves invites condensation on the beans. Freeze them in smallish portions (like a week's worth), and once they come out, store at room temperature.
- Wrap/pack them VERY well (vacuum-sealed is good).
- Wait until the beans have come up to room temp before opening the package. This prevents the condensation issue.
The freezer does change the flavor though, and not for the better in my opinion. So, I believe that the cold does damage the oils, but it's better than letting a large quantity of beans go to waste.
Next I tried the Airscape canisters, and eventually the Prepara EVAKs, which are basically the same, and they are equipped with a lid with a one-way valve that slides inside the canister, collapsing with the coffee as it gets used up. Definitely better than a mason jar, or a crock or a tupperware, which still trap air inside them. But it wasn't until I started using the Airscapes for just that week's worth of coffee, and vacuum sealing the rest that I started to see real results.
Now, all this is only necessary, if you don't use up your beans as quickly as others. I know people who drink so much coffee, that they don't bother to store it carefully - they just drink it before it can go stale. And that's certainly a viable strategy. But for the rest of us, who don't have as good access to fresh beans, and want to buy it in bigger quantities, buy whole beans, grind right before you brew, and store the beans away from light, heat, oxygen, and moisture.