Fourteener Coffee Club
Quick answer: how to store coffee beans in Colorado
In a Colorado kitchen, a sealed, opaque canister in a cupboard away from the stove and the sunny window is enough for a bag you will finish in two weeks. The dry air works in your favor: the National Coffee Association's case for the freezer rests on humid climates, and Denver's air averages about 52 percent relative humidity. Save the freezer for extra bags. Expect a sealed bag to swell when you carry it up to the mountains; that is lower air pressure, not a problem. By the Specialty Coffee Association's measure, whole beans stay fresh for about three weeks after roasting and ground coffee for about an hour.
What stales coffee, and how Colorado changes it
The Specialty Coffee Association names four enemies of freshness: oxygen, moisture, temperature and time. The NCA adds light. Here is each one against the conditions up here.
| Enemy | What the research says | The Colorado angle |
|---|---|---|
| Oxygen | Cutting the oxygen in a container to 0.5 percent can extend shelf life up to 20 times (SCA). | The thin air does not help here; oxygen still gets in every time the bag is open. |
| Moisture | A high moisture environment speeds up aging (SCA). Coffee is hygroscopic: it takes in moisture and odors from the air (NCA). | Denver's average relative humidity is about 52 percent, and the city has a cool semi-arid climate with generally low humidity. |
| Heat | A 10 °C rise in temperature can double the rate at which coffee gives off gas (SCA). | Denver's average July high is 89.9 °F, and a parked car at a trailhead gets far hotter. |
| Time | Beans lose carbon dioxide fast for the first 20 days after roasting, then much more slowly (SCA). | A bag roasted in Colorado starts that clock closer to your kitchen. |
| Light | Clear canisters let in light, which can hurt the taste (NCA). | Denver averages about 3,100 hours of sunshine a year, so a glass jar on a south window sill is a poor home for beans. |
Dry air: when the freezer is worth it
Colorado is a dry state. Wikipedia's Colorado article says the state averages only 17 inches of precipitation a year, and its Denver article gives the city 14.48 inches. Denver's climate table, built on NOAA data from 1961 to 1990, puts average relative humidity at 52 percent, from about 48 percent in July to about 57 percent in December.
That weakens the usual argument for freezing. The NCA's reasoning is that coffee soaks up moisture and smells, that home containers leak a little air, and that cold storage pays off most where the air is humid. On a Front Range counter, moisture is the smaller worry, so a closed canister in a cupboard covers a two-week bag.
The freezer earns its space when you stock up, say after a trip to a roastery in Durango or Crested Butte. SCA research found that storing freshly roasted coffee well below freezing slows its loss of gas a great deal, without stopping it. The NCA's conditions for doing it: a truly airtight container, a week's worth out at a time, and the rest back in before condensation forms.
Cold winters and hot cars
A package left on a winter porch is not ruined by the cold. Denver's average January low is 18.7 °F, and the SCA's freezer results point to cold slowing staling, not speeding it. The catch is bringing a frozen bag into a warm, heated room. The NCA flags condensation as the risk with cold coffee. Our own habit follows from that: leave the bag closed on the counter until it reaches room temperature, then open it.
July is the harder month. If each 10 °C of extra heat can double the rate of degassing, a bag riding in the car all afternoon while you hike ages much faster than one in a kitchen cupboard. Bring it in with the groceries, not after the errands.
Why coffee bags puff up in the mountains
Freshly roasted coffee is full of gas. The SCA measured that up to 2 percent of the weight of fresh roasted beans is gas trapped inside them, released fastest in the first 24 to 48 hours. A one-way valve on the bag lets that gas out without letting air in.
Altitude adds a second push. Air pressure falls as you climb: Wikipedia's article on atmospheric pressure gives a rule of about 1.2 kPa less for every 100 meters near sea level. By that rule, the air in Denver, at 5,280 feet or about 1,600 meters, presses on a bag with roughly a fifth less force than at sea level. That estimate is ours, from the rule. Wikipedia shows the reverse with a photo of a plastic bottle sealed at about 14,000 feet and crushed on the way down. A bag sealed low and carried up a mountain pass swells for the same reason. It is physics, not a failed seal.
The gas is useful for a while. The SCA reports that in the first week after roasting, carbon dioxide in a sealed valve bag can reach 80 percent of the air inside, pushing oxygen out and slowing the change in aroma. So for that first week, the roaster's valve bag, rolled down and clipped, is a good place for the beans, even on the drive up I-70. When the zipper or clip stops holding, move them to a sealed, opaque canister, the kind of container the NCA recommends.
Buy fresh, in small amounts
No container stops the clock. The NCA suggests buying in amounts that last one or two weeks, and the SCA's degassing work shows why the first three weeks after the roast date matter most. Our post on whether a coffee subscription is worth it works through the numbers. Beans hold their gas far longer than grounds, which is the case for whole bean coffee; the glossary entry on degassing covers the gas itself.
Buying from a roaster in this state shortens the trip before the clock even starts. The Fourteener Coffee Club sends a 12 oz bag from a different independent Colorado roaster each box, every 2 or 4 weeks, for $16.99 a bag. The two-week plan fits the NCA's one-to-two-week window. First bag free, you pay $7.99 shipping on that first box, and you can skip or cancel anytime. Choose your plan.
Coffee storage questions for Colorado
Should I freeze coffee beans in Colorado?
Only the beans you will not use within a few weeks. The NCA ties the benefit of freezing to humid climates, and Colorado's air is dry. If you freeze, use a truly airtight container and take out a week's worth at a time.
Does coffee go stale faster at high altitude?
We found no source that says altitude itself speeds staling. The SCA's research points to oxygen, moisture, heat and time. Altitude does make bags swell, because the air pressure outside them is lower.
Why is my bag of coffee puffed up?
Fresh coffee gives off carbon dioxide, most of it in the first days after roasting, and the one-way valve cannot always vent it as fast. Carry the bag uphill and lower outside air pressure makes it swell more.
How long do coffee beans stay fresh?
The SCA's Coffee Decoded column puts whole beans at about three weeks from roasting and ground coffee at about an hour after grinding, using gas loss as the guide.
Sources
- National Coffee Association, Storage and shelf life (buy for one or two weeks; airtight, opaque containers; light; hygroscopic; freezing and humid climates; condensation; one-week portions)
- Specialty Coffee Association, Preserving Freshness: A Race Against Time (the four enemies; 0.5 percent oxygen and 20 times; moisture; 10 °C doubling; 2 percent gas; 24 to 48 hours; 80 percent CO2 in valve bags; freezing)
- Specialty Coffee Association, Coffee Decoded: What is freshly roasted coffee? (rapid degassing for 20 days; about three weeks for whole beans, about an hour for ground)
- Wikipedia, Coffee (the one-way valve keeps air out while letting gas escape)
- Wikipedia, Denver (5,280 feet; cool semi-arid climate with low humidity; about 3,100 hours of sunshine; relative humidity from NOAA 1961 to 1990; precipitation; July high; January low)
- Wikipedia, Colorado, Climate section ("Much of Colorado is very dry, with the state averaging only 17 inches (430 mm) of precipitation per year statewide")
- Wikipedia, Atmospheric pressure (about 1.2 kPa per 100 meters; the crushed bottle photo). The "about a fifth" figure for Denver is our estimate from that rule.
- Letting a cold bag warm up before opening it is our own advice, drawn from the NCA's warning about condensation.
By Joe McRose, Fourteener Coffee Club. Updated . Storage guidance from the National Coffee Association; freshness research from the Specialty Coffee Association; Denver climate from Wikipedia's Denver article (NOAA data); Colorado precipitation from Wikipedia's Colorado article; air pressure and altitude from Wikipedia.