"Brewing is the extraction into water of desirable substances from the coffee bean, in amounts that produce a balanced, pleasing drink."
-- "On Food and Cooking: The Science and Lore of the Kitchen" by Harold McGee
People who get into coffee tend to follow similar paths. They switch over from automatic drip to manual brewing methods to better control the process. They start buying whole beans and preaching the virtues of freshly roasted coffee.
Chemex and press-pot (aka French press) coffee makers are popular among this set for a number of reasons: They're inexpensive, easy to clean, easy to use and relatively quick and consistent. But the best thing about both is they allow for easy manipulation of the variables that affect the taste of the coffee.
The principle factors are the water temperature, the "dose" of coffee (ratio of coffee to water), the size of the grind and the time that the water is in contact with the beans.
It's easy to learn the basics of these two methods. Press pots work by mixing hot water with ground coffee, letting it circulate and brew, then pressing a fine sieve down through the beaker, filtering out the coffee sediment.
Chemex brewers are one type of manual drip maker, so details about this method are generally applicable to other manual drip methods. With a Chemex, coffee is placed in a paper filter that sits in the top half of an hourglass-shaped glass vessel. Water is gradually poured over the grounds. The thickness and type of the paper helps control the way the water circulates through the coffee and drips into the holding vessel below. (For the basics of Chemex and press-pot brewing view the videos at post-gazette.com/food.)
Getting past the basics means understanding the theory of how each brewing method works and how changing one variable affects the others.
Too high a temperature, too fine a grind or too long an extraction time and your coffee will be bitter. Too coarse a grind, too low a temperature or too short an extraction time and it will be weak and flavorless.
Grinding your beans at home is essential to getting a great cup of coffee. The quality of your grinder has as much of an effect as the quality of your brewing method.
Blade grinders cut through coffee beans with a flat blade that rotates in a circular motion. It is impossible to achieve an even grind with a blade grinder, and if you grind long enough for finely ground coffee, damaging heat often builds up. More expensive burr grinders grind coffee between conical burrs for an even fineness. A numbered dial controls the size of the grind, but over time the burrs may slightly shift, so make sure to pay attention to the actual size of the grounds as well as the numerical setting.
The grind size of the coffee used in a Chemex will determine how quickly the water passes through the coffee. Since the Chemex works by filtering the water through a thick paper filter, reasonably good results can be achieved using a blade grinder. For Chemex (or other manual filter methods) start with a medium grind of about 0.5 mm, then adjust.
When working with a press pot, an even grind is essential. While you want relatively coarse particles so that they won't pass through the sieve in the plunger, there are still adjustments that can be made in the size of the grind. Start with a coarse grind of about 1 mm, then adjust. Finer coffee will necessitate more pressure when plunging the press. There should be some pressure exerted, but it should not be difficult. By exerting firm, even pressure it should take about 10 to 20 seconds to filter the coffee, depending on the size of your desired grind and the size of the pot.
For a cleaner cup (less sediment), remove the lid just before plunging and gently stir the coffee grounds still floating at the top -- the thick end of a chopstick works well for this task -- then carefully skim off the fine grinds left on the surface.
Filtered water is ideal for making coffee. While you can use tap water, even good tasting tap water is adding flavors to your coffee that may not enhance it. When making coffee, always use cold, fresh water (water that hasn't already been boiled) and always boil it in a kettle or other vessel used only for that purpose.
The ideal temperature is between 190 and 200 degrees. Water boils at 212 degrees, but it cools rapidly when exposed to air. Controlling temperature is probably one of the most difficult aspects of these types of brewing methods.
For the greatest ease, it's possible to use an electric kettle with a 200-degree press pot setting and to pour directly from the kettle into the Chemex or press pot. You also can keep water at a low boil, pour it into a glass measuring cup or pitcher, then immediately pour it into the Chemex or press pot.
Remember when using the Chemex that it's essential to keep the grounds wet so they stay in the proper temperature range. You also don't want to overfill the upper portion of the brewer.
For a press pot, maintaining temperature is a little easier. It's a good idea to preheat the beaker by pouring in hot tap water or boiling water, then pouring it out just before you add the ground coffee. You also want to keep the top of the press pot on while you brew, to prevent heat from escaping.
A good basic recipe to start with is 10 grams (or one level two-tablespoon scoop of whole beans) per 6 ounces of water. Weighing your coffee isn't essential, especially if you measure whole beans rather than grounds.
The Chemex brew time should be between 5 and 8 minutes. A finer grind will slow down the water, a coarser grind will speed it up. Remember to saturate the grinds evenly each time to make sure that proper extraction is taking place.
The press pot brew time will be 4 minutes for a standard, course grind, but it should be shortened for small press pots and for finer grinds to between 2 and 3 minutes. Use a timer; do not guess.
• Cleaning: If anything you use to make coffee (including your coffee mug) is coated with a fine brown film, then you're not cleaning thoroughly enough to remove coffee oils. These oils become rancid, negatively affecting the coffee taste. Wash glass in warm soapy water after every use. Wash metal parts in the dishwasher (if dishwasher safe) or scrub thoroughly with dish soap and hot water. Hard to clean components such as stainless steel thermoses are best cleaned using a little powdered detergent and boiling water or a paste of baking soda and water.
• Storage: Store whole beans in an airtight, opaque container in a cool location. Beans can theoretically be stored in the freezer, but they must be thoroughly protected from freezer burn, other smells and the moisture-removing effect of the cold. If you're not willing to seal daily doses in individual airtight containers, it's not worth it.
• Freshness: Ideally beans should be used within 10 days of roasting, but top-quality beans that are a couple of weeks old probably will still taste better than mediocre beans that were roasted three days ago, especially if you're storing them properly.
Do not grind your beans before you are ready to start brewing. Ideally, less than a minute should elapse between grinding and starting the brewing process.
Only brew as much coffee as you can drink immediately. If you want to make coffee to drink later, transfer it to a thermos. Reheating destroys all of the delicate, complex flavors of quality coffee. If you don't like the taste of your coffee once it's less than scalding, consider whether you could buy better beans. Quality coffees taste better as they cool.
All of these factors may make coffee brewing seem overwhelming, but it's only complicated if you try to change everything you're doing all at once. With time the ritual of making coffee can give as much pleasure as the drink itself. Coffee brewing becomes a hobby as well as a drink, and, only when something becomes something we do for pleasure rather than just a chore, do we start really paying attention.
Refurbished or discounted coffee makers and grinders: