When one thinks about a cup of coffee, the roasted bean is the first thing that comes to mind. Quality beans are certainly crucial, but equally important is the good water used because hot H2O is the solvent that leaches the flavors and oils out of those beans. A cup of regular coffee is about 98.75 percent water, leaving only 1.25 percent for the soluble plant matter, so it goes without saying poor water quality can ruin even the tastiest coffee beans. All the countless hours of work by farmers, roasters and numerous others involved in getting coffee to market are for naught if, in the end, the consumer brews their beverage with bad water.
It sounds simple to say water is just two hydrogen molecules for every one of oxygen, but the chemistry of water is actually very complex. Its makeup can change seasonally and because of other factors such as city water treatments, variable sources, nearby construction, etc. Water also has many gases and minerals dissolved in it, in addition to floating bacteria and dirt. A simple charcoal filter will remove things like dirt and odor but is not much help when it comes to mineral content. Much the same way it pulls flavors from coffee, water extracts minerals as it moves through the ground or in pipes. Some of those minerals, such as iron, can produce bad coffee tastes or colors. Some, on the other hand, can be good; coffee just tastes better when brewed with good water that has a fair amount of calcium dissolved in it. One measurement the Specialty Coffee Association of America uses to count the number of minerals dissolved in water is by measuring the total dissolved solids (TDS). The total dissolved solids are measured in parts dissolved solids, per million parts water (ppm). A TDS reading is partially a measure of whether water is what is considered soft or hard. The ideal range for TDS is between 125 and 175 ppm. Water with a very high TDS reading (hard) extracts coffee flavor less readily. The ideal range for calcium hardness is between 17 to 120 ppm. Things such as iron, chlorine and chlorinates should not be present in a reading. If your water does not fall into the desired range, the solution may be a water softening or filtration system.
Personal taste is always the most important factor when evaluating the quality of brewed coffee, but don’t forget tools can be used to help measure strength and extraction and allow for more taste control. Also, all water filtration systems have parts that must be replaced on a regular basis to ensure optimum performance. In general, replace carbon filters for in-line water filtration systems every three to six months. For reverse osmosis systems, the filters and membranes should be changed once every year. But these are just guidelines; anytime you notice debris or scale on your equipment, or detect odors or off-flavors, replace your filtering elements immediately.
Always remember that with its thousands of different flavors and chemicals (such as caffeine), coffee is an extremely complex beverage. No good extraction of those desirable tastes is possible without good water. Do great coffee justice and make sure your water is held to the same high standard as your beans. For more information about using good water and proper filtration, call 800-835-5943 or email firstname.lastname@example.org.