The second most common question in our café, next to “do your roast your own beans,” is “how should I store my coffee?”
“What’s the best way to keep coffee fresh? Can I store it in my freezer?”
A tough question that requires some scientific research.
First, let’s tackle what we know about freshly roasted coffee. We know coffee gives off CO2 for a few days after it’s roasted. We know that coffee left in open oxygen deteriorates more quickly than coffee protected from air.
In our café we store coffee in bags with one-way valves to let gas out and keep oxygen from getting in.
We also know our bags aren’t great for the environment, but compostable bags with one-way valves have yet to hit the market, so we stick with the bags with the best storage quality. Since this month is Earth month, we took another look at packaging. How much does that one-way valve really affect the lifespan of a cup of coffee?
Turns out, it affects coffee in a big way.
Last month we roasted our Colombia Huila Monserrate (March 30) and packaged it in six different ways. Each week after the roast, we blindly tasted each coffee, diligently trying to discern the palatable differences between them.
Over three weeks the coffee aged and each Monday we tested the six differently packaged coffees for new flavors during the aging process. Here’s what we found:
–The multi-ply bag with one-way valve scored high marks of freshness evenly throughout the three weeks. The coffee retained chocolate and sweet notes and some liveliness in its body.
The Kraft bag with no valve scored high the first week but deteriorated rapidly in the second and third weeks, developing a chalky mouthfeel and some grassy notes.
The silver tin with valve scored similarly to the bag with valve, particularly in the second week. The coffee showed a beautiful balance of caramel and nuts.
The silver tin without the valve scored a C average with decent chocolate and earth notes but became flat as it aged.
The espresso hopper showed more promise in the first week but the coffee in weeks two and three became thick and developed a toasted or char-like characteristic.
The heat-sealed multi-ply bag with valve, opened in the third week, showed the most complexity compared to the other coffees in week 3. Milk-chocolate base, earth and cinnamon.
So what did we learn? The valve seems to help the most in the final weeks of the coffee’s life.
–Keeping coffee longer than two weeks? Have it heat-sealed in a bag with a valve to make sure it retains its springy-ness in the cup.
–Drinking it sooner rather than later? Either the bag with valve OR a silver tin with valve will keep the coffee fresh and ready for enjoying. As long as it can let the gasses out and keep oxygen from getting in, the coffee should last a few weeks and keep the palate happy.