When it comes to the bean, much of the coffee talk concerning post-roast is about how to preserve the flavor. Once coffee is roasted we all know that the clock begins to tick. We spend a lot of effort looking for preservation methods. Vacuum packing, freezing, mason jars, and inert gas packing all are tried by the home user as well as the coffee industry.

      Combining convenience with preservation has been a topic for about the last five years or so. Coffee pods are pre-packed little puck-like parcels filled with pre-ground coffee that are dropped into espresso machines and other brewers. There are a few of these proprietary systems, each using their own design of pod. A number of years ago I tried the Phillips Senseo system. The coffee that came with the machine tasted good (as in "drinkable without grimace"). The next batch they sent me was stale when it arrived, due to the fact that the pods were not protected from the air and of dubious age.

The K-Cup proprietary cup system shown in cross section.
1 - the stiff, plastic outer cup
2 - the inner filter which contains the coffee
3 - the plastic-lined, foil seal

      Keurig is another proprietary system that uses an advanced, proprietary design call a K-Cup. These little plastic cups contain a filter bad inside that is filled with coffee then the top of the cup is sealed wth a plastic-lined, foil cover. The user simply drops the cup into the machine and closes the lid which punctures the foil as well as the bottom of the cup. Press a button and preheated water flows through the K-Cup and into your coffee cup. The coffee is protected to the point that the cups foil seal will bulge as the coffee out-gasses or the air expands from warmth.

      The Keurig system make a very nice cup of coffee giving the user a lot of choices of coffees and roasts from many companies as well as tea and hot cocoa. But how well does it preserve the coffee? For quite some time I had a number of K-cups stashed away and I had forgotten about them. I decided to pull some out and try them. Your first question should be, "How old are they?" I examined one from Green Mountain and on the side of the cup was printed, "Best if used by 06/05." I had around three dozen cup in a large, heavy-duty, zip-lock bag and I took a long smell inside the bag once I had opened it, and there was absolutely no hint of a coffee aroma, a testament to the design and materials used to make the K-cups. Thesew cups should have been used up 4½ years ago! After seeing that I did not expect much, and that's just what I got.

      I brewed three different cups and they all tasted the same- thin, lacking in flavor depth as well as body. Nothing to cause me to expectorate it into the sink, but also not much there to motivate me into finishing the cup of coffee. They did lack that ashy, burnt aftertaste that often comes from stale coffee, but the taste and aroma was only worthy of mention in a chapter on this website.

      To investigate further, I took a fresh K-Cup and tore open the seal to sample the aroma of the coffee contained inside. After opening I gave the coffee a little shake then smelled it. It was not bad, but on the other hand it didn't smell very much like coffee at all. I questioned myself as to what the aroma was but couldn't place it. With a furrowed brow and a feeling of wonder, I smelled the coffee once again, but this time the aroma was quite nasty. It was sort of "industrial-stale" with a plasticky follow, with no hint whatsoever that what I was smelling was coffee.

      That experience was so bewildering I tried it again. This time I made sure to fully open the foil lid and shook the coffee about. Same as the previous test. First sniff OK. Wait a few seconds. Second sniff nasty.

      The next day I tried the same test on my wife. She inhaled once and questioned what she had just smelled. She inhaled a second time and recoiled. Same result. I even went one step further and after opening the cup I poured the coffee into my had and we sampled the aroma. Same result. This ruled out any effect that might have been caused by the aroma of the cup itself or any gas trapped in the cup over that length of time.

      So I call this one more data point tallied up for the fact that once coffee has been roasted the clock ticks. With the exception of deep freezing, once roasted there are changes going on in coffee we often refer to as "staling." Proteins and oils change, flavor elements break down, and a big part of this is oxidation of these elements. To prevent this we store the coffee in air-tight containers. These may be one-way-valved bags, vacuum storage of some sort, or flushing with nitrogen or carbon dioxide. But this does not stop the chemical breakdown taking place in the coffee bean. Once exposed to the air the coffee hungrily accepts the oxygen. It's what is credited for making Illy coffee good the first day and quite stale the second after initially opening the can, and I believe it is what happened here.

So two morals-
      First, buy fresh-roasted coffee beans, and make coffee from fresh roasted beans.
      Second, if you use K-cups, don't keep them around for five years.