I just got a pound of microroasted, local coffee and am curious what the optimal way to store it is (what temperature, humidity, etc)
In a cool, dark, dry, place and whenever possible vacuum sealed.
The oils in roasted coffee degrade as they are exposed to air (oxidization) as well as heat. As with just about any foodstuff moisture accelerates the spoiling process as well. You should store your coffee in completely sealed, insulated, opaque containers. If you have the ability, vacuum pump the air out of the container for ultimate shelf-stability. Even without vacuum storage you can preserve beans for a long time by placing them inside a ziplock bag or coffee bag with a 1-way air seal and pushing as much air out as possible and then following the above method of airtight, dark and cool storage. Following these guidelines should help to ensure the freshness and flavor of the beans for as long as possible.
I would add to not store it in the refrigerator or freezer. It would fare better at room temperature and dry than cold where it could be exposed to food smells and moisture. You didn't ask, but also drink it as soon as possible if it's ground. Whole beans will keep for awhile but ground coffee will start to go stale very quickly, even if stored properly.
The National Coffee Association article on How to Store Coffee advises this:
It is important not to refrigerate or freeze your daily supply of coffee because contact with moisture will cause it to deteriorate. Instead, store coffee in air-tight glass or ceramic containers and keep it in a convenient, but dark and cool, location. Remember that a cabinet near the oven is often too warm, as is a cabinet on an outside wall of your kitchen if it receives heat from a strong afternoon or summer sun.
The commercial coffee containers that you purchased your coffee in are generally not appropriate for long-term storage. Appropriate coffee storage canisters with an airtight seal are a worthwhile investment.
An update to the NCA article adds:
While there are different views on whether or not coffee should be frozen or refrigerated, the main consideration is that coffee absorbs moisture – and odors, and tastes – from the air around it [...]
If you choose to freeze your coffee, quickly remove as much as you need for no more than a week at a time, and return the rest to the freezer before any condensation forms on the frozen coffee.
Room temperature, open-air is fine (for a while)
"Micro-roasted" implies that you purchased the beans where the roasting was performed on premises. That means it was probably roasted recently, within a couple of days. Roasts vary, but generally a bean will remain fresh for a week or two, open-air, room temperature from the time of roasting. One person might take two weeks to use a pound of beans. Just keep it in the closed bag, away from temperature extremes.
No coffee will taste fresh after months, no matter the storage. There are gas-valve tins and bags available online. Coffee beans are quite dynamic. The chemistry continues long after the roasting heat is removed. The logic behind one-way valves is that fresh-roasted beans continue to release gasses that were trapped in the beans. I roast coffee beans and store them in a dark cabinet in a wire basket, exposed to the kitchen air. No bean survives more than 10 days. Most often, the flavor actually improves after a few days.
Adding some thinking out of the box to all the great answers, I would say:
You should not store it, instead try buying less quantity, consistent with your rate of consumption, more often. In this way it's quality will be as near with its production quality.
As an argument I will point out that oxidization is an effect that can not be prevented easily and once exposed to the atmosphere the coffee interacts with the environment via the moisture it absorbs and all the smells contained within it. That is why Illy seals its containers with Nitrogen to try and isolate it from the environment, as much as possible, till it is opened.
The big killers of coffee taste in roasted coffee beans are:
- moisture and airborne aromas
In the roasting process the coffee bean doubles in size and gives off most of its moisture content. After roasting the coffee bean becomes super hygroscopic. (i.e. it wants to absorb all the moistures and airborne aromas in the atmosphere that surround it). Oxygen reacts with the delicate coffee oils and turns them rancid, and heat brings the coffee oils to the surface where the oxygen can easily attack it.
So a completely air-tight container that has not been used to store any other products is a great start. Non porous ceramic or glass is preferred. Make sure light can't penetrate,and it's kept in a cool place away from any heat source. Don't grind it until you plan to use it. While roasted coffee bean quality can be maintained for a few weeks without loss if handled properly, ground coffee can loose significant value within 24 hours. I am no fan of the fridge/freezer option.
In a cool, dry place, away from elements and preferably sealed / vacuum sealed
No paper bags or canvas, something clean, and preferably with one of those moisture wicking buttons
My favorite thing is a "Coffee Vault" from Mystic Monk. It has two seals and and has a 'lock' to the second seal. I use to work in a place where you could smell things easily, my coworkers would love it every morning hearing the seal unlock and the vacuum seal taken off as they would smell the coffee as if it was a fresh roasted bag. Every morning without fail. I think they are made by AirScape or Planetary Design or something like that.
For christmas this year my wife got me a Zurich Coffee Vault , which is supposed to be the highest rated and best coffee vault. Its really good, the coffee scoop I think is a big odd, and I like it, but to me its still nothing compared to the AirScape / Planetary Design Coffee Vault.
I saw no paper bags or canvases, as those are easily affected by the elements and even by the coffee itself, and often what you are given coffee in. I have found that if you keep the coffee in that, the coffee oils can come off in the bag possibly affecting the next batch of coffee in that. Though this is true for anything, even with the Coffee Vaults or plastic storage, if not cleaned properly between uses you will get a different tasting coffee. The paper and canvas I have also had experiences where the flavor of the canvas or paper starts coming through in the coffee, and I am sure this is also true for some other organic materials.
It's interesting how negative folks can get about freezing coffee.
There are a few places where freezing coffee has been tested to do really good things.
1) one good thing - is extending life (and flavour) of the roasted bean - when it's put down as soon after roasting as possible, and is only frozen/unfrozen once.
here's a ref that goes into detail of a taste comparison between the frozen and fresh versions.
to quote from PAGE THREE (!) of this rich evaluation
Maximizing your coffee's usable lifespan: Freezing is a viable method of preserving the freshness of very fresh coffee. Exactly how long the usable lifespan of coffee can be extended with freezing is unknown, although we do know that if frozen immediately that lifespan extends to at least 8 weeks. In this experiment, a very specific methodology was employed, and exactly how far one can deviate from it and expect to get good results is unclear. The previously frozen coffee we used was frozen immediately after roasting, within about an hour, in semi-airtight packaging in a very cold freezer (about -15°F / -26°C). It was then defrosted, only once, within the same packaging before it was exposed to outside air, reducing or eliminating the possibility of condensation.
So, for espresso - 8 weeks good.
A personal note: i've found a bag of my fave beens tucked in the back of the freezer 8m after putting it back there. Wow, i was so delighted with the flavour of the pour over - expecially when it was not that bean's season. Felt like cheating :)
SO why not try it yourself? you may be delighted months from now with the pleasure of out of season loved flavours.
2) another recent bit of work from bristol (i think) has been deliberately freezing the dose overnight before grinding. Bean bits seem to grind more evenly when frozen.
From an industrial perspective, the yield of extraction is paramount. Grinding colder coffee beans produces a more uniform particle distribution, with a decreased particle size. While the decreased particle size will tend to speed up extraction due to the larger surface area, the increased uniformity should minimise the amount of wasted bean, which is discarded without being extracted to completion. Whilst active cooling of either the coffee beans or burrs is energy consuming, the benefit of cold coffee grinding may offset this cost with more efficient extraction from the smaller particles.
How bout that - and that this does something lovely for the taste. It's covered in Nature! it must be true
PS - with storing roasted beans, since air is the big killer (more than even light - not much research shows light affects quality surprisingly) - there are a couple cans that are pretty good:
- vacu vin - this is a US amazon link to see it -they make the type of canister you literally suck out the air with a hand pump -and this really does extra air - generally i put the bag into the container rather than loose beans - and then extract and when you take out the bag it's like it was vacume packed - cool!
- coffeeVac - another amz link for info is pretty super too: less fussing around - but not a vacume - its lid presses air out.
- Airspace link again is sort of like coffeeVac but more intrigued that coffeeVAC - the tin is stainless steel; the plunging lid pushes out potentially more air since it squihes down to the level of the coffee.
in my experience using each of these all the time, the CoffeeVac is easiest to use, the VacuVin i trust the beans i care most about to - esp if wanting to keep them frech over a few weeks or more, and the Airspace - well i have it so i use it but it may be more intrigued than it's worth - with two lids: the plunger and then the top so nothing falls into the can.
Anyway, coffeeVac is likely most affordable and effective.