How to Keep Your Coffee Fresh
Written by Paul Katzeff
The Importance of Properly Storing Your Coffee
Coffee does not have immortality. If a roasted bean is left exposed, it will slowly stale within one week and even sooner if ground. However if properly stores, coffee can have a shelf life up to six months.
Various Causes of Coffee Staling
Staling is caused, in order of most harmful to least harmful
- Exposure to air (Oxidization)
- Exposure to heat
- Exposure to moisture
- Exposure to light
Roasted Coffee beans are composed of approximately 800 organic chemical compounds. Many of these organic compounds create the flavor you love.
There are sugars, alcohols, acids, Ketones, Aldehydes, minerals and all sorts of volatile flavonoids and antioxidants. When these organic compounds are exposed to air, many of them will combine with the Oxygen, forming new organic compounds that don’t taste good. The coffee becomes flat, losing its brightness and personality. This doesn’t happen immediately– it begins when you open a vacuum packed bag and the process continues on for about a month. The great flavor of high-quality coffee lasts longer at first but their fall over the cliff is more dramatic then lesser coffees. This is because the taste of lesser coffees when fresh often resembles stale coffee.
All chemical reactions are speeded up by heat, so we want to keep the coffee at a low temperature. That will go a long way in saving the flavor.
Oxidation can be slowed down or speeded up. Temperature is the factor and since Staling is caused, essentially, by oxygen combining with other compounds, we want to keep the beans cool but not frozen.
Your coffee beans are pretty devoid of moisture. When we put green raw beans into the roaster they are about 11% moisture. When they exit the roaster after being at high heat (400-465 degrees) they are really dry. But like a dry sponge, they will attract moisture from the air. This is Osmosis. Moisture softens the beans and further enables organic compounds to combine and change, reducing flavor and speeding up the oxidization process.
It takes an awful lot of light to make coffee stale; if you address the air, heat, and moisture issues, then the light will become a small factor. On it’s own, in my experience, light alone will take a long long time to damage coffee beans. However, if coffee beans are exposed to prolonged sunlight, then heat becomes the primary culprit.
How to Keep Your Coffee Fresh
- Air: Keep your coffee from contact with air by storing your coffee in a closed mason jar or a container with a good lid. It you plan to use your coffee in just under a week, the refrigerator is fine. Remember: coffee is under 5% moisture so it will absorb flavors if not in an airtight container.
- Heat: Keep your fresh coffee away from heat; Cool is best. Refrigerator is recommended. Freezing coffee is a good thing to do if you are going on vacation and want to save your coffee for months. However, we don't recommend this for daily use as the frozen grounds will lower the water temperature in your hot coffee brewer. This will lower the extraction rate causing a weaker brew. The hotter the beans get while in storage, the faster the organic compounds will combine and become stale components.
- Moisture: This plus heat = stale in 24 hours.
- If you address the problems of Air, Heat and Moisture correctly, then Light will have little effect on your coffee.
- Time: The best way to deal with time is by not buying more than you can use in 7 days.
- Don’t open the coffee bag until you are ready to use its contents.
- Close the bag and within the first three days, transfer the coffee into an airtight container. No need to purchase an expensive kitchen accessory. Just use a quart mason jar and seal it with a lid.
- Cool is better than room temperature. Since warm air rises, store your sealed containers on your lowest shelves.
We prepare our coffee in opaque packages which are flushed with nitrogen to remove all oxygen and moisture in the air. We are dealing with every factor that will impact flavor deterioration. For good measure, we vacuum seal and package our coffees within 18 hours of being roasted.