Is fresh best?

Freshness is often praised as the ideal for our food. Fresh vegetables, bread, juice are all sought after and said to be the best. For some items this is very true. However a lot of food is better with some age on it. Sauerkraut, cheese, wine and many other things are best after they have been allowed to age and change. The same is true for coffee. Some technical data now. During the roasting process many physical and chemical changes occur that stress the bean and cause it to grow larger and the complex molecules break apart into simpler forms. These changes in the make up of the coffee cause biproducts to occur, such as water, sugars and carbon dioxide. The degassing process (CO2 evaporation) can take from 4-24 hours to occur. The variables here depend on the bean type, roast level and if the coffee was ground or not. Degassing is a necessary step in the roasting process. Many large roasters grind the beans right after roasting and use nitrogen gas to push out the CO2 immediately and stale the coffee. If degassing is not allowed to happen the tins or bags will puff up and could explode from the pressure. This is why the one-way valves were developed for packaging. They allow the CO2 to escape with minimal entrance of oxygen. Degassing is also required to happen before you brew a pot of coffee. If you grind and try to brew coffee right after roasting, the rapid rate of degassing can actually repel the water causing an overflow and a big mess. One reason to always wait until the next morning before you have a "fresh" pot of coffee.

Over the years I have met a lot of different roasters and connoisseurs. One gentlemen had dates on all of his home roasts and knew that a Harrar for example tasted the best for him after 5 days while a Sumatran was best after only 3. I tend to recommend enjoying your coffee within a week or two of roasting. Even in a valved bag there is oxygen and the oxygenation of coffee causes a stale bitter taste. My advice for coffee drinkers is to buy what you are going to use within a short period of time. Whole bean coffee has a shelf life of roughly 1-2 months maximum and ground coffee only about 1 month maximum, regardless of packaging. Fresh when it comes to coffee is more like cheese. Give it a little time and get a sense for how the flavor changes. Don't have a freshly roasted cup unless you want to clean up a big mess.