Brewing -- How to Get the Most Out of Your Coffee
"Good coffee deserves good brewing."
-- Donald Schoenholt, Gillies Coffee, NY
There's certainly a lot of swill being served in popular coffee shops, so if you'd like to rise above the crowd by serving the best possible cup, an objective brew analysis of your coffee can help you see where you are and where you need to go. In the meantime, here are some guidelines to get you started. (If you're looking for brewing-at-home info, go here.)
The most frequent and egregious problem is not using the right proportion of coffee to water, almost always not using enough coffee. The correct proportion to start with is 4 oz of coffee to 64 oz (1/2 gallon) of water. (For the metrically inclined, that's 60 grams per liter.) There's some leeway in that number -- say, 3.5 to 4.25 oz per 1/2 gal -- but if you're using less than 3 oz, you're better off buying on price and avoiding specialty coffee altogether. Most airpots nowadays are much larger than 1/2 gal -- a 2.5 liter airpot can hold over 80oz -- so you would need to start with at least 5oz of ground coffee.
The second most frequent problem is not keeping the water in contact with the coffee long enough to extract all the flavor. In a drip brewer, the contact time should be 4 - 5 minutes. That is, the time from when you push the "Start" button until the last of the coffee runs out of the basket, should be 4 - 5 minutes. Often the depth of ground coffee in the brew basket is too shallow and the water simply runs through too fast, a situation exacerbated by not using enough coffee in the first place.
The solution is to use a narrower brew basket to give a greater bed depth of ground coffee. (If you have a Bunn airpot brewer, the stainless steel "Gourmet basket" p/n 34559.0000 may help.) You can also try using a finer grind which helps the extraction process by slowing the flow through the bed as well as exposing more surface area of the coffee particles to the water on its way through.
Two other things to check -- even if you have enough coffee in the proper brew basket, you have to get the water hot enough. The proper brewing temperature is 200°F ±5°F. This used to be more of a problem than nowadays with modern brewers that use electronic thermostats. Last, the spray head (where the water sprays over the ground coffee) may not soak the ground coffee bed evenly. Again, modern brewers designed for specialty coffee generally do well but they do require maintenance, especially earlier FETCO units with plastic spray heads. If you have older Bunn equipment, you want a spray head with more and smaller holes, and fortunately most of the spray heads are interchangeable among brewer models.
The specialty coffee movement has inspired brewer manufacturers to produce equipment far superior to what was available only a few years ago. I personally favor FETCO and Bunn, and while they, Newco, Curtis, and others do make the right stuff, you still have to use it properly. Pulse brewers from all of these manufacturers turn the brewing water on and off during the brew cycle for proper extraction, pre-wet the grounds to keep them from floating, and have convenient front panel programmability, features that can make your coffee into an entirely different beverage.
If all else fails, read the instructions. Check out The Coffee Brewing Handbook by Ted R. Lingle, an SCAA publication that has more than you ever wanted to know about brewing coffee, available from the SCAA Store.
Notes on brewing at home.
same proportion of
coffee-to-water and same 200° water temperature apply no matter what method you
use or the amount you're brewing. I think the best way to brew coffee
at home is to use a French press (also called a melior or "press-pot").
They're relatively inexpensive and available in many sizes from 1-cup
on up. The French press fixes all of the common brewing problems at
It's easy to get the proportion right: use two (2) level tablespoons of coffee to one (1) coffee cup (5oz - 6oz size) of water. (In metric terms, that's 10g of coffee per 170 ml of water.) Boil the water to get it hot enough, then pour it over the coffee in the press. Stir the grounds into the water to saturate them thoroughly. Let it stand for 3 minutes. Push the top down and serve. If there's any left over, put it in a thermos to keep it hot.
If you don't like the somewhat muddy character of the cup you get with a French press, a small brew funnel with a cone filter is another good choice. Remember, same coffee-to-water proportion, use water just off a boil, and pour the water over the grounds a little at a time to get that all-important extraction. Chemex-brand filters work especially well since they're thicker than most and don't let the water flow through so quickly.