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The good news is that few municipal water systems have high concentrations of sodium or potassium. The following are characteristics determined by the SCAA for superior extraction: Water should be odorfree; have a clear color; be free of chlorine, iron, and sulfur compounds; have a TDS level of 150 milligrams per liter; have a calcium hardness of 3-4 grains (51 to 68 milligrams per liter); have a measure of total alkalinity at or near 40 milligrams per liter; have a pH of 7–8; and have a sodium level of 20 milligrams per liter. Achieving the Optimum Formula Often I see situations where there is much more filtration than necessary; many of the problems with your water can be solved with minimal filtration. Particulate filtration will almost always be needed. These filters get out the majority of turbidity, and the most common size is five microns. A micron is a unit of length equal to one micrometer. Carbon filtration is the most commonly used filtration, and in many cases, a five-micron prefilter with a carbon block filter run in-line is all that is needed. Water softening systems will minimize the hardness ions, calcium, and manganese through ion exchange, in which the sodium ions or hydrogen ions replace the hardness ions. Reverse osmosis (RO) is a membrane filtration method that removes many types of large molecules and ions from solutions by applying I would argue that there is no one perfect water, but rather many perfect waters. It really depends on what you want to get out of your coffee. pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane, and the pure solvent is allowed to pass to the other side. By continuously flushing the minerals from the membrane, the water produces desirably low TDS, and the other concentrated minerals are flushed out to waste. This results in considerable water waste. In many cases, RO is the best solution for water with high TDS. It should be noted that RO has the potential to make water more aggressive, so getting a correctly engineered and installed unit is very important. There is much more to water than most of us ever realized when we got started in the coffee industry, and believe me, the rabbit hole is deep. I do believe that water has to become a bigger topic throughout our industry—it's that important. We have to pay attention to how much we use and take into consideration the recyclability of the water we do use. We don't take for granted all the work behind the amazing coffee we get to work with; shouldn't we give water that same respect? 62 barista magazine