Coffee is a product known in food safety as a “shelf stable” item. In essence, what this means is that old coffee will never kill you.
That said, in industry circles, coffee is known as an incredibly un-shelf stable, or “volatile” product.
This pertains, not to the toxicity of the seed, as with what food safety officials concern themselves; it speaks rather to the degradation of the aromatic compounds and flavor oils contained within coffee’s structure.
A very quick overview of what coffee is:
Coffee is the seed of a cherry-like fruit that grows exclusively in the tropics. Using varying methods, the fruit is picked, the seed removed, then dried, then cooked or roasted into what you know by sight and smell as coffee.
Prior to roasting, coffee is green in color with a pronounced sweet, grassy fragrance. Brewing coffee in this state is unpleasant, trust me. It’s quite astringent and grassy with a barnyard-like aroma.
When you cook the coffee, you are changing the chemical makeup and structure of the seed. Ultimately, roasting forms volatiles and transforms sulfur-containing compounds that are responsible for much of the aromatic aspects of coffee as we know it. Furthermore, the Maillard reaction produces other compounds and transforms lipids, both of which are quite susceptible to oxidation. Perhaps the most important of these changes- or at least as a catalyst of the degradation of the important flavor compounds, oils, and volatiles- is the decrease in overall mass of the coffee coinciding with the increase in its structural porosity. What this means, is that the coffee’s structure becomes honeycomb like. The cellulose matrix creates a more permeable area for oxygen to enter and wreak some havoc.
How storage affects the shelf life of coffee:
Packaging coffee is done for two major reasons. Firstly, you package coffee to carry it (duh! You’d be a fool walking around with a pocketful of coffee and lint). Secondly, you package coffee to protect it from oxygen and environmental factors (most notably moisture, heat, and light).
With this second reason in mind, the more your package blocks the elements from contacting your coffee, the longer it will remain at peak flavor.
The invention of the flavor-lock valve (a valve that allows for the release of CO2, but prevents oxygen from entering) and better barrier-type packaging has increased coffee’s shelf life ten-fold.
When storing coffee, another major element of the rate of degradation is the state of the stored coffee. Otherwise put, whether the coffee is ground or whole bean.
Coffee stored in a ground state is at a distinct disadvantage due to the increased amount of surface area available to the oxygen and environmental factors.
How does this all impact coffee you buy here?
Most (not all) barrier packaging and valves have come at a big cost. While they protect your coffee in incredible ways, they are equal parts as destructive on the environment.
For this reason, we package our coffee in Kraft bags with a corn-based polyliner, which, after removing the metal tin-tie, are 100% compostable.
In these bags (according to our cuppings), your coffee will remain at peak flavor for about a week and a half.