How to Keep Your Coffee Fresh

Written by Paul Katzeff

The Importance of Properly Storing Your Coffee

Coffee is a perishable product. There are over 800 organic compounds in a roasted coffee bean. There are water-soluble compounds (the sweetness and bright acidity) and oil-solubles (the tars, tannins and bitters).

These oil and water-solubles easily combine with oxygen when exposed to air, heat and light to form new organic compounds that change the flavor profile of fresh-roasted coffee. So, you will find as time goes by, that those flavors are muted, at first, and then evolve into a flat, sour and unsatisfying taste. However, the caffeine does not break down and its bitterness remains to overwhelm your palate. It is advisable to stop this “staling “ process by storing your expensive coffee properly if you want that great flavor you expect to be there.

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

Air (oxidization):

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.

Heat:

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.

Moisture:

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.

Light:

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.