How Long Does Coffee Last? Understand When (and How) Coffee Goes Bad
We’ve all eyed that bag of decaf coffee sitting in the back of our cupboards we keep around for guests and wondered to ourselves how long it has been there and whether it is still good to drink.
Coffee is a complicated beverage and understanding when coffee goes bad isn’t quite as simple as checking an expiration date. While it may technically be safe to drink coffee for a long period of time after it has been roasted, you may not want to.
The key principle to understand is that coffee beans begin to lose their flavor the moment they are roasted. The farther away from the roasting date they get, the less ideal they become. Unfortunately, there is no magic marker to tell you when your coffee beans are no longer at their peak performance.
Instead, you’ll need a little background on coffee so you can trust your own judgment.
The Journey of a Coffee Bean
First things first: Unless you're one of those lucky souls that gets to see it up-close on a coffee vacation (yes, those are real), you've probably wondered: what are coffee beans and how did they get to your kitchen?
Coffee beans begin as a fruit called a coffee cherry that grows on coffee trees in geographic areas between the Tropics of Cancer and Capricorn. Once cherries are bright red, they are ready to be harvested.
Next comes processing. There are a few different methods of processing but the two most common are dry processing and wet processing.
In dry processing, coffee cherries are sorted by hand to remove debris and damaged cherries. Then they are spread out and left in the sun for up to 4 weeks, intermittently raked or turned by hand to ensure even drying. The resulting berries have a hard outer shell and maximum moisture content of 12.5%. The beans are stored until they are sent to a mill for hulling, at which point they are officially green coffee beans ready to be sold.
In wet processing, the beans are cleaned and then pumped using a special machine that separates the flesh and skin from the bean. The bean is left with a slippery outer layer called the mucilage and another thin outer layer called the parchment. The beans are cleaned again and put into tanks where the mucilage breaks down naturally leaving just the bean and parchment. Everything is washed again with clean water to ensure the mucilage is flushed away. Then the beans are dried using a similar sun-drying process as the one mentioned above that takes 8-10 days. Just before selling, the beans are hulled to remove the parchment layer and then sorted and graded.
Coffee is shipped around the world in its green coffee bean state, and that’s how it arrives at your local roaster. The roasting stage is where most of the characteristic aromas, flavors, and colors of coffee beans form and variations in the roasting process are what gives different coffees their unique profiles. To see a more in-depth look at the roasting process, check out this video here.
Coffee in its natural green bean state is comprised of dozens of different chemicals and compounds: carbohydrates, amino acids, lipids, etc. During the roasting process, amino acids and sugars within the coffee beans begin a series of chemical chain reactions called the Maillard Reaction that creates coffee’s color and taste. The result is the transformation of a dozen different organic compounds into more than a thousand, all giving coffee its characteristic flavor and aroma.
Gases, mainly carbon dioxide, form inside coffee beans during the roasting process and are rapidly released immediately after roasting. That’s why many roasters follow the 12-24 hour degassing rule, where they let freshly roasted coffee beans sit for at least 12 to 24 hours to allow the rapidly escaping carbon dioxide to leave the coffee beans, since it can negatively impact extraction and therefore the taste of the resulting coffee brew.
After degassing, coffee is packing and sealed in airtight containers or special packaging that keeps it away from light and air. One of the biggest elements that accelerates the deterioration of coffee beans after roasting is oxygen. Water and heat have the ability to change coffee’s properties, as we can observe through the brewing process. However, through oxidation, oxygen molecules steal electrons from other molecules creating unstable free radicals that are responsible for reactions we call rusting, aging, and staling.
For us, that means exposure to oxygen slowly robs coffee beans of their flavor. This is one of the reasons that coffee experts emphasize using freshly ground coffee for brewing: increasing the surface area of coffee beans by grinding them up increases their exposure to oxygen and causes them to prematurely lose their flavor before you are ready to brew.
From farm to coffee roaster to carefully sealed packaged on the shelves of your local coffee shop or grocery store, that is how coffee beans make their way into your possession.
Fresh Coffee: What is That?
So at what point in the process described above is coffee considered “fresh”? After all, it would seem that the “freshest” coffee beans are the ones recently harvested, right? While that is true for most fruits, the way we consume coffee is much different so our standards for what is fresh must change as well.
Most people in the coffee industry agree that the question, “how fresh are these coffee beans?” is really a question of how long ago they were roasted. That’s because coffee doesn’t expire the way that perishable food items in your refrigerator do. Whether or not coffee is “fresh” really becomes a matter of its flavor.
Freshness can be thought of as the time frame in which your coffee beans are at their peak flavor performance. For most coffee experts, anything beyond that timeframe is when coffee loses its value. Of course, whether or not you agree depends entirely on how you value your coffee: for its flavor or for any number of other reasons (routine, caffeine intake of choice, etc.).
The tricky and somewhat confusing part is that even among coffee experts, there is no consensus for standard measures we can use to tell if coffee has passed its “fresh” mark and become stale. The first compounds to evaporate once oxidation has begun are the flavor compounds responsible for the sweet-smelling, buttery, and earthy aromas and flavors. Most coffee shops will go by the individual roaster’s suggestions for when to take their product off of the shelves since every roast and every coffee is slightly different.
The question is, should you do the same in your home? The closest we come to a general consensus on how long coffee beans last is approximately three weeks (assuming they are still in whole bean form and have not been ground yet). However, we’re going to bet that if you drink coffee every day and have developed a taste for what to expect, you’ll likely notice a difference after the first week. Does that mean your coffee is bad? Not necessarily.
Many companies use special packaging to prevent their beans from spoiling between the period of time that the beans leave the roaster and arrive in your kitchen. For example, it is common to package coffee with a valve-sealed bag that allows carbon dioxide to escape but prevents oxygen from entering.
However, once you get your beans home and open the container, the oxidation process begins and the freshness clock starts ticking. This moment right here is when your beans are fresh, assuming you bought them from a quality supplier with a marked roasted date on the side of the packaging, and when you have the chance to extend your coffee beans shelf life with proper storage. Warning: do not pre-grind your beans. Grinding rapidly accelerates the loss of flavor and aroma so it should only be done right before you plan on brewing coffee.
How to Store Coffee
The two main enemies of coffee beans are oxygen and moisture, so it’s best to keep your beans in a cool, dry place. Exposure to sunlight is also harmful to your coffee beans as it can prematurely heat coffee, altering the flavor and aroma before you are ready to start the brewing process.
Ideal storage for your coffee beans is in an airtight container and placed somewhere away from moisture, heat, and light. While mason jars may be a pretty way to store coffee, they let in too much light and don’t always provide an adequate seal. There are some specialty containers on the market designed for coffee bean storage that are worth researching and trying out if you are serious about keeping your beans healthy.
The airtight seal also comes in handy if you live in an area with a naturally higher humidity index. Coffee beans, once placed in an adequate container, are most appropriately stored in a cupboard or pantry where the temperature will remain relatively constant. Climates that are unusually humid or dry may impact storage, which is another reason why coffee containers are worth the investment.
While we don't recommend this next method, but one common way people store coffee is by putting it in the freezer. Coffee that is frozen cannot be allowed to thaw: as soon as it begins to thaw, the condensation begins the extraction process (making coffee). If you then put those beans back into the freezer, you’ve done the opposite of what you intended to do and altered the chemical state of the beans. When you really are ready to brew the coffee, it will already be halfway through the extraction process. Additionally, you don't just have to talk our word for it. The SCAA does not recommend freezing coffee and also considers refrigeration a failure, as it may cause the lipids and moisture to emulsify.
How Long Do Coffee Beans Last?
We can't in good conscience tell you want you might want to hear, which is that coffee can last a super long time. Just because your coffee beans might look and smell fine doesn’t mean you should use them.
If you’ve properly stored your coffee beans in a cool, dry place inside an airtight container, we feel that the beans will be okay for a maximum of three weeks. And considering how quickly coffee loses its flavor over time, it might not taste like anything if you purchased sub-par coffee beans.
On the other hand, once your beans are ground, we recommend not using them after one week. Already at the one week mark, the flavor quality has been lost significantly. We've said it before, and it might even be worth putting on our gravestone: Only grind your coffee beans immediately before brewing.
When Coffee Goes Bad
There are some stages of the coffee bean that really are dangerously icky.
If your coffee was somehow introduced to water and or was not packaged properly, it is no longer safe to consume. Rancid, moldy coffee is not the same as flat, flavorless coffee that is simply past its prime.
Do not brew coffee if there is any indication that it was not sealed properly, is wet or shows signs that it was introduced to water, smells of mildew, or shows visible signs of mold. Those are all signs that coffee has officially crossed the line into “unsafe to consume.” It is no longer a matter of taste: coffee that has gone rancid will make you sick.
Otherwise, enjoy extending your coffee’s “flavor life” with the knowledge and tips above—we know you’ll notice the difference.