Brewing Water
Water Sources
The three main sources of water are municipal, ground, and surface waters, and they can differ widely in quality because of their differing routes through the environment. Most brewers rely on municipal water supplies for their water while other brewers may rely on ground water. The water source can have substantial effect on its quality and variability of the beer.
Municipal Water
While some large breweries may have their own wells, small breweries typically receive their water from the municipal water supplier. Municipal sources in the United States typically treat and verify that their water is safe to drink. Similar requirements often apply worldwide. Municipal water companies typically rely on surface water sources (e.g., rivers, lakes, and reservoirs) and/or groundwater sources (springs and wells) for their water source. A variety of processes can affect the quantity and quality of water from these sources through the year.
Ground Water
Wells draw groundwater from underground aquifers. Where these aquifers are isolated from lakes, rivers, marshes, and salt water, their groundwater quality tends to be more consistent (constant) throughout the year. Wells that are not isolated from lakes and rivers may be subject to the same water quality variability of the lake or river. Like surface water sources, the mineralization of groundwater is affected by the geology of the aquifer. As water percolates through various rock types, it dissolves various anions (bicarbonate, sulfate, nitrate, and chloride) and cations (such as calcium, magnesium, sodium, potassium, and perhaps traces of iron and manganese).
Surface Water
In contrast to ground water, surface water comes from lakes, rivers, and man-made reservoirs and dams. Thus, the water is not constant in quality and quantity as seasonal changes and the occurrence of rain will have an impact on temperature and composition. Compared with underground water, surface water usually contains only small amounts of minerals and it is susceptible to organic load (agricultural and urban runoff), microbiological contamination as well as inorganic and organic compounds, such as pesticides.
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