Perhaps the most daunting task for a coffee shop owner and home brewer is obtaining an extraction that is truly tasteful, elegant and represents the most complete cup the coffee being brewed has to offer. Filter drip coffee at its best is a delicate balance of weights, grinds, time and water quality and of course, fresh roasted coffee.
Lets begin with Coffee Brewing 101. The first and foremost key ingredient in coffee is of course, water. Not any water will do, either. Coffee brewing and extraction is especially sensitive to the amount of hardness and total dissolved solids present in the water. Water without mineral content, such as reverse osmosis and distilled water, doesn’t extract the flavor out of the coffee grounds and yields a flat, under-extracted brew. Soft water is great for washing dishes, your clothes and hair, but again, creates problems in coffee brewing. Soft water does not extract medium roasts well and will miss the bright, alive nature associated with these roast levels. In fact, most people with soft water will prefer a dark roast because it is the only roast they can get any real flavor out of using this type of water. People who are lucky enough to have a 7-10 grain hardness with total dissolved solids of 130-160ppm will be able to brew the tastiest of coffee and will be able to enjoy the full dimension and richness of flavor available in the light to medium roast coffees.
Number two on the list of items necessary for a golden cup of coffee is a brewer that heats to 195-200 degrees and has a brew time of at least 3 1/2, but preferably 4 minutes in length. Too short of a brew time and the coffee won’t extract properly and the flavor will actually taste weak and straw-like. Too long of a brew time and you end up with too many solubles in your coffee. The ultimate goal on solubles is 1.35-1.5%.
Number three, the grind of your coffee is very important. A medium grind is preferred. Too fine a grind and you will extract bitter alkaloids that are better left in the filter basket. Too coarse a grind yields a weak flavorless cup.
Number four, volume of ground coffee to water ratio. This is a very important aspect that you will need to define by your taste. The rule is one tablespoon per 6 ounces of water (the standard cup measure in your home brewer). I would suggest you brew 6 cups with 6 level tablespoons to start. Develop a base formula to brew from and vary it according to your preferences with experimentation. This ratio of coffee to water will differ with different roast levels and will vary with decaffeinated coffees. Dark roasts and decafs will need a little more in the filter basket to achieve the same flavor intensity. I find that for a 12 cup brewer, 8-9 level tablespoons of a medium ground coffee will give a flavorful cup that I can serve to my guests. What I really like is the first 4 ounces that comes out of the brewer, but then again, this ruins the coffee flavor for anyone else. Note: this cup is not intended for the faint of heart.
Last but certainly not least, is brewing a coffee that is freshly roasted and is at its peak flavor. I prefer coffee within the first 24 hours of being roasted but within the first week is quite acceptable. Remember that coffee off-gases 50% of its volatile aromatics in the first 5 days after it is roasted. I like to capture this flavor in my cup.
Hope this wasn’t more than you wanted to know. Happy Brewing!