Basic Brewing Principles
The first step in producing a good cup of coffee is to start with fresh beans. Think of coffee like fresh produce, not bulk goods. Coffee is a seasonal crop and should only be harvested at certain times during the year. Once processed, the raw coffee bean is fairly durable, but its flavors tend to mellow over time. While there are stories of green beans sitting in warehouses for a decade a more, with rare exception, the best coffees will have been picked within the past two years.
Once roasted, the beans become more volatile. Despite that fact, most large-scale roasters, if they provide a sell-by date at all, will keep beans on the shelf for up to a year after roasting them. However, coffee’s most delicate and complex flavors are really only present for about the first two weeks after roasting. That is because from the moment coffee beans are roasted, they begin releasing carbon dioxide. While the beans are de-gassing, the carbon dioxide creates a protective envelope that preserves the most delicate flavor constituents from oxygen-induced degradation. Once the gas is depleted, a process that generally takes up to two weeks, the coffee is no longer protected and begins to rapidly stale when exposed to air. Large, centralized coffee roasters get around this problem by roasting all their beans relatively dark. Unfortunately, the flavor created by the roasting process itself, which is more shelf stable, overwhelms many of the more complex and interesting flavors inherent to the beans.
In order to preserve the freshness of your coffee, grind only the amount you need just before brewing it. Once the beans are ground, staling occurs very rapidly, in a matter of hours rather than days or weeks. If you don’t have a grinder, it really makes sense to get one. Even a $20 blade grinder can greatly improve the quality of coffee you drink at home. A significant step up from that is a good burr grinder or coffee mill. Coffee mills offer much more consistent grinding, especially if you use any brewing methods other then drip. Refrigerating or freezing the beans or ground coffee does not slow down the de-gassing or staling process. However, keeping the ground coffee in an airtight container, such as a small mason jar can limit oxygen exposure if you will be traveling and won’t have access to a grinder.
Use enough coffee. It doesn’t really pay to scrimp on the amount of coffee you use if the result is a weak and disappointing cup of coffee. The Specialty Coffee Association of America recommends that you use 10 grams of coffee per 6 ounces of water. If you don’t have a gram scale, an average coffee scoop holds about 7 grams of coffee beans (that’s before grinding). Of course, the amount of coffee you use is highly dependent on the brewing method. For example, when using a French press increase the quantity of coffee by 15-20%. Any technique will take a some tweaking to get results you can be satisfied with.
There are a number of good brewing techniques, but whichever you prefer, there are three factors to ensure you get the best results: Use filtered water, heat the water to between 195 and 205 degrees Fahrenheit, and finally, make sure that you thoroughly wet the grounds during brewing. Unfortunately, only a few automatic drip machines are designed to heat the water consistently to the proper temperature and disperse it adequately over the grounds. Drip machines are also not well designed to deal with very fresh coffee, which “blooms” considerably due to the high levels of gas released when ground and then exposed to hot water. However, if you are willing to spend a little more time in the morning, a manual drip method offers many advantages over an auto-drip machine including control over the temperature of the water and the dispersal of water through the grounds as well as the ability to brew different quantities of coffee, another thing auto-drip machines are not designed well to do.
With these principles in mind, you should be ready to start brewing a better cup of coffee.