The source of water has a direct affect on its suitability for brewing.  Some brewers rely on municipal water supplies for their water while other brewers may have private wells, springs, rain barrels, or other local sources for their brewing water.  The water source can also have substantial effect on its quality and variability.

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 (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.  For instance, large volumes of snow melt or rainfall can provide softer water to a surface water source while that surface water can become more mineralized from groundwater inflow at other times of the year.  Additionally, the municipal water source might vary between a variety of surface and groundwater sources as they are consumed through any dry weather periods.

Most municipalities are required to disinfect their drinking water and provide a disinfection residual in their distribution system (piping).  Halogenated (typically chlorinated) compounds are frequently used to provide disinfection and a residual of disinfectant in the water lines.  If the raw water is unfit for drinking due to hardness or other excessive mineralization, the municipality may treat the water to reduce hardness or mineralization prior to delivering it through their distribution piping.

Differing ionic content of brewing water can affect mashing performance and flavor perceptions in the finished beer.  Ions in water come primarily from the soil and rock minerals that the water contacts as it flows through the environment. In areas where the soil and rock are less soluble, the degree of mineralization of the water may be lower.  However, when the soil and rock are more soluble, significant concentrations of ions may dissolve into the water.  The effect of these dissolved ions on brewing is presented in the following sections.

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 type of soil or rock that the groundwater flows through. Groundwater flowing through limestone and gypsum formations typically has more hardness ions than groundwater flowing through granite or sandstone.

Springs provide another source of groundwater.  As with the sources listed above, understanding the quality of spring water is still important.  The taste and ion content of the water must be suitable for brewing and the water should be free of chemical and microbe contamination.  Landfills, waste dumps, and wastewater facilities are examples of facilities that might impact a spring source.  A spring water source is not a guarantee that the water is safe to drink or suitable for brewing.

Rivers, lakes, and reservoirs may have additional variability in their water quality due to natural algae and microbes that may create strong taste and odor in water during warmer weather.  These taste and odor components can make it past some municipal water treatment methods and leave the water with undesirable taste and aroma that may persist into the finished beer.

When presented with a water source with poor brewing qualities, additional water treatment by the brewer may help correct the water’s faults for brewing usage.  Water treatment alternatives such as water distillation, reverse osmosis, carbon filtration, lime softening, water boiling, mineral addition, or acid addition may improve the brewing quality of a water source.  Understanding the source of water and its limitations and variability can help maintain the quality and consistency of a brewer’s product.

Information on this page is based on Water Knowledge by Martin Brungard. 

Minerals and Brewing Chemistry

Minerals dissolved in brewing water produce important effects on the overall chemistry of the brewing process.  The ions from these minerals alter the water’s pH, Hardness, Alkalinity, Residual Alkalinity, and Mineral Content.  

These interrelated components are the most important factors in defining the suitability of water for brewing.  Adjustments to any one factor can have an effect on the others.  

pH is a measure of the acidity or basicity of an aqueous solution and is related to the concentration of hydrogen (H+) ions in a solution.  A very small percentage of water molecules (H2O) naturally split into hydrogen (H+) protons and hydroxyl (OH-) ions.  A neutral pH of 7.0 indicates a balanced population of those ions in pure water (at 25°C).  Acidic solutions have a pH of between 0 and 7 while Basic solutions have a pH between 7 and 14.  The pH of typical municipal water supplies generally lies between 6.5 and 8.5, but may exceed those bounds since pH is not regulated by the Safe Drinking Water Act that governs drinking water quality in the U.S. 

Hardness in drinking water is primarily due to its calcium and magnesium content. High concentration of calcium or magnesium ions produces hard water and low concentration of those ions provides soft water. The hardness or softness of water does not indicate its suitability for brewing as both very soft water and very hard water can be utilized as long as the appropriate alkalinity is provided for mashing. Since there is often a minimum calcium content desired in brewing water, moderately hard to hard water may be desirable for brewing. Water hardness varies regionally and by source. Much of the Western and Midwestern U.S. often has high hardness while coastal or mountainous regions may have lower hardness. 

Alkalinity is a measure of the “buffering” capacity of an aqueous solution and its ability to neutralize strong acid and resist pH change. Alkalinity is defined as the amount of strong acid required to lower the pH of a sample of the water to a specified pH (typically 4.3-4.5).  Alkalinity is generally due to the concentration of carbonate (CO3), bicarbonate (HCO3), and hydroxyl (OH-) ions in water.  Higher alkalinity water requires more acid to change the water’s pH.  In typical drinking water, alkalinity is directly related to the concentration of bicarbonate in the water. Alkalinity is often reported using terms such as “as CaCO3” and care must be used to avoid confusing it with similar hardness results. Like hardness, alkalinity tends to vary on a regional basis. 

Residual Alkalinity is brewing-specific value that is derived from both the water’s Hardness and Alkalinity to help evaluate potential mashing pH conditions. RA was described in the 1940’s by Paul Kohlbach.  He showed that during mashing, calcium and magnesium in the brewing water react with phosphatic compounds (phytins) in the malt to produce acids that neutralize the brewing water’s alkalinity.  The water’s alkalinity is effectively reduced by its hardness. This interaction between the brewing water’s hardness and alkalinity is expressed by RA. RA is an indicator that is specific to brewing and is a factor in defining the suitability of water for brewing. 

Mineral Content

Dissolved minerals (ions) are typically present in all natural waters, although rainwater may have very low ion concentrations.  The type and concentration of those dissolved minerals can have a profound effect on the suitability of water for brewing use, its mashing performance, and the flavor perception of beer.  A discussion of dissolved minerals that are a concern to brewers is presented below.  Mineral salts create ions when they dissolve in water.  These ions are either positively-charged (Cations) or negatively-charged (Anions).  

Undesirable Ions
The first consideration is that brewing water should have high quality and be safe to drink.  This requires that the water have no pollutants and have little or no iron, manganese, nitrites, nitrates, or sulfides.  Organic pollutants and chemical contamination have no place in beer.  The following ions are commonly found in water supplies, but their concentrations must be low in order to not affect the finished beer.

Iron may be tasted in water at concentrations of greater than 0.3 parts per million (ppm or mg/L) which may also be reported as 300 parts per billion (ppb or µg/L).  Iron has a very metallic taste that is easily conveyed into the finished beer. Popular guidance says that the iron content of brewing water should be below 0.1 ppm to avoid tasting it in beer. Rust-colored deposits on plumbing fixtures may be an indicator of elevated iron content in water. Even in the absence of metallic flavor, iron in brewing water can produce a Fenton reaction that can oxidize beer and reduce its life.

Manganese may be tasted at concentrations of greater than 0.05 ppm or 50 ppb.  Manganese has a very metallic taste that is easily conveyed into the finished beer.  Black-colored deposits on plumbing fixtures may be an indicator of elevated manganese content in water.

Nitrate is not a great concern in brewing, but should generally be less than 44 ppm in the water source to protect infants that may drink the water.  Nitrate concentrations may also be reported in the form, Nitrate as Nitrogen (NO3-N).  44 ppm nitrate is equivalent to 10 ppm nitrate as nitrogen.  Children and adults can tolerate higher nitrate concentration and the 44 ppm limit may not be a concern in brewing.  However, nitrate in brewing water should reportedly be less than 25 ppm (De Clerck, 1957).  High nitrate concentration in the water may be converted to nitrite in the mash and nitrite becomes poisonous to yeast at levels above 0.1 ppm.  If elevated nitrate levels are found in water, associated ions such as nitrite and ammonia should also be tested for.

Sulfide compounds that might be exhibited as sulfur or rotten-egg aromas should not be perceptible in the water.  

Major Ions in brewing

These ions can also be grouped in another way.  Calcium, magnesium, and bicarbonate produce hardness and alkalinity that affect the mash pH.  Sodium, chloride, sulfate, and magnesium ions affect flavor, which adds important nuances to beer perception.

Calcium is typically the principal ion creating hardness in water.  It is beneficial for mashing and enzyme action and is essential for yeast cell composition. Typical wort produced with wheat or barley contains more than enough calcium for yeast health. In the mash, calcium reacts with the malt phosphates (phytins) to lower the mash pH by precipitating calcium phosphate and liberating protons (H+). Calcium improves the flocculation of trub and yeast and limits the extraction of grain husk astringency.  It also reduces haze and gushing potential, improves wort runoff from the lauter tun, and improves hop flavors.  The ideal range for calcium ion concentration in ales may be 50 to 100 ppm although exceeding this range may cause phosphorus (an essential yeast nutrient) to precipitate excessively out of solution.  

Oxalates are natural component of brewing grains. Since oxalates are precipitated through complexing with ionic calcium, insufficient calcium in brewing water may leave excess oxalate in the wort which can contribute to beerstone (calcium oxalate) formation.  

A minimum concentration of 40 ppm calcium is recommended to reduce beerstone formation potential.  Calcium concentration of less than 40 ppm can be tolerated in brewing water for beers that benefit from less mineralization (ie. pilsners and light lagers) with the understanding that additional measures may be needed to ensure adequate beer clarification, and beerstone removal.  

Brewing with very low calcium content water does not impair fermentation since barley and wheat provide sufficient calcium for yeast health. The primary difficulties with brewing with very low calcium water is that yeast flocculation may be impaired and beerstone formation may affect equipment. Both of these problems can be alleviated through practices such as lagering, filtering, and active maintenance for beerstone removal. The calcium content of brewing water should generally conform to the calcium content that the original yeast evolved to. Therefore, an English ale yeast might expect high calcium content water while a Czech lager yeast might expect very low calcium content.  (Brungard, 2015)

Another consideration is that the calcium content for brewing water may be tailored to increase or decrease yeast flocculation. For example, if a yeast is known to drop out prematurely, then reducing calcium content could be employed to reduce that tendency. For most lager brewing, low calcium content water is more likely to produce better results. Brewing water with low or no calcium content can be OK for Lagers.

Increasing the calcium content of mash water is a useful tool for reducing the pH of the mash water.  Calcium content has little effect on beer flavor but it is paired with anions that may increase the minerally flavor of the water when present at elevated concentrations. A problem with high calcium content brewing water is that the calcium displaces magnesium from yeast and that can have a negative effect on yeast performance. Avoid excessive calcium content when yeast performance is below expectations. (Note: adding calcium to sparging water does not reduce the water’s pH or alkalinity since there are few malt phytins present to complete that reaction.  An acid must be used to reduce the alkalinity and pH of sparging water.)

Magnesium is typically the secondary ion creating hardness in water.  It accentuates flavor with a sour bitterness when present at low concentration, but it is astringent at high concentration.  Magnesium is a yeast nutrient and an important co-factor for certain enzymes.  Like calcium, magnesium reacts with the malt to lower the mash pH, but with a reduced effect compared to calcium.  The preferred range for magnesium concentration is 0 to 30 ppm.  Exceeding 40 ppm is not recommended.  A minimum of 5 ppm magnesium is known to be desirable for good yeast flocculation, however a typical barley or wheat mash grist will contribute more than 5 ppm magnesium to the wort for proper yeast flocculation and it is not necessary to add magnesium to brewing water unless it is desired for its flavor effects.  Increasing the magnesium content of mash water is not a useful tool for reducing the pH of the mash water since the allowable concentration range for magnesium is small.

Sodium – The sour, salty taste of sodium accentuates beer’s flavor when present at modest concentration.  It is poisonous to yeast and harsh tasting at excessive concentrations.  It accentuates flavor when used with chloride and imparts roundness to the beer flavor.  The preferred sodium concentration range is 0 to 150 ppm, but the upper limit should be reduced in water with high sulfate concentration to avoid harshness.  A practical maximum concentration of 100 ppm is recommended for brewing, but brewers should recognize that waters from the historic world brewing centers have less than 60 ppm sodium.  Keeping sodium concentration below 60 ppm is therefore recommended in practice.  Most tasters find that “salty” flavor becomes apparent in drinking water when its sodium content exceeds 250 ppm. While low sodium is desirable, some beer styles such as Gose may have much higher sodium concentration (~250 ppm) as part of their desired flavor profile, but that sodium is typically added to the post-fermented beer. 

Chloride – Chloride accentuates fullness and sweetness and improves beer stability and clarity.  The ideal range is 10 to 100 ppm, but the upper limit should be reduced in water with high sulfate concentration to avoid harshness or minerally flavor.  When brewing with sulfate concentration of over 100 ppm, limiting the chloride content to around 50 ppm is recommended.  The minerally flavor of Dortmunder Export may be due to the typical 130 ppm chloride concentration along with the 300+ ppm sulfate content in Dortmund’s water.  Brewers of juicy IPAs have reported that brewing liquor with around 150 ppm chloride and 75 ppm sulfate provides fullness without lingering too long on the palate.  Chloride does not make beer maltier, it helps any malt in the beer to be perceived more readily. Be aware that the chloride ion is not the same as the disinfectant, chlorine and should not be confused with it. 

Sulfate – Sulfate provides a sharper, dryer edge to highly hopped beers.  The ideal concentration range is 0 to 350 ppm, although the concentration should typically not exceed 150 ppm unless the beer is highly hopped.  Sulfate concentration above 350 ppm has been reported to produce sulfury aroma in finished beer.  The use of the historic Burton water profile (sulfate greater than 600 ppm) may not produce ideal ales for that reason.  Including some sulfate in brewing water can help dry the finish and avoid an overly full or cloying finish, even in malty beer styles. Sulfate does not make beer bitter, it helps any bittering in the beer to be perceived more readily.  Brewers should recognize that high sulfate level in brewing water along with either high sodium or chloride levels can produce harsh or minerally flavor in beer.

Bicarbonate – Bicarbonate is a strongly alkaline buffer that is typically responsible for the alkalinity in most drinking water.  Malt acids produced during mashing do consume some of the bicarbonate in the brewing water.  When there aren’t enough malt acids to neutralize the brewing water’s bicarbonate content, the mash pH may not fall into a desirable range, which may reduce enzyme action and make hop flavors more harsh.  When brewing lighter colored beers, bicarbonate is generally undesirable in brewing water and is best kept below 50 ppm or should be balanced with additional calcium to reduce the Residual Alkalinity of the brewing water.  When brewing darker colored beers, some bicarbonate may be needed in the mash water to balance the higher acidity provided by the dark-colored grains.  High bicarbonate concentration and its resulting alkalinity is not desirable in sparging water due to the increased potential to leach harsh-tasting silicates, tannins, and polyphenols into the wort.  


Acids can be an important component in brewing water adjustment.  Acids come in solid and liquid forms and all add hydrogen protons (H+) to the water and move the pH of a solution lower.  Acids also add their unique anion to the water. 

Frequently, the anions have distinctive flavor that may compliment or degrade beer flavor when they are present in beer at levels above their taste threshold.  Some acids are more perceptible in beer than others. 

Phosphoric acid is more difficult to perceive in beer since beer contains similar phosphatic compounds.  It is typically the most flavor-neutral acid used in brewing and the various phosphate anions remain relatively undetected to most tasters at under 1,000 ppm.

Hydrochloric and Sulfuric acids can add chloride or sulfate ions that may be desirable in the flavor profile. The contributions and limits for those ions are discussed in the section above. 

Citric, Malic, and Tartaric acids can add fruity or estery perceptions to the beer. The typical anion taste thresholds for most tasters are: (Citrate = 150) (Malate = 100) (Tartarate = 600) ppm.

Lactic and Acetic acids can impart their unique flavor to beer.  Lactic is smooth while Acetic is pungent. The typical anion taste thresholds for most tasters are: (Lactate = 400) (Acetate = 175) ppm.

Minor Ions

Below is a list of ions that may be present in brewing water. Some are essential for yeast nutrition in small quantities and may be harmful above a certain amount. Others are contaminants and are always undesirable. In city water, these are mandated by law to be below harmful levels, but well water may pick up problematic amounts of various things. 

This varies by region. Iron, for example, may be found in some limestone-derived water, while heavy metals can sometimes be found in mountainous areas. EPA/Clean Water Act for drinking water are listed with the maximum contaminant level (MCL listed as ppm) requirement. (US EPA website www.epa.gov.)

Aluminum is a common and widespread element, almost all metallic aluminum is produced from the ore bauxite (AlOx(OH)3–2x). Bauxite occurs as a weathering product of low iron and silica bedrock in tropical climatic conditions. In brewing aluminum can be involved in haze formation. Experiments have shown it unlikely to leach from cooking vessels into wort during normal brewing operations.

Antimony is a metal found in natural deposits such as ores containing other elements. The most widely used antimony compound is antimony trioxide, used as a flame retardant. The major sources of antimony in drinking water are discharge from petroleum refineries; fire retardants; ceramics; electronics; and solder. Removed by coagulation/filtration and reverse osmosis.

Arsenic is a semi-metal element in the periodic table. It is odorless and tasteless. It enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. Approximately 90 percent of industrial arsenic in the U.S. is currently used as a wood preservative, but arsenic is also used in paints, dyes, metals, drugs, soaps, and semi-conductors. Agricultural applications, mining, and smelting also contribute to arsenic releases in the environment. Removed by adsorption media, ion exchange, coagulation/filtration, oxidation/filtration, and point-of-use or point-of-entry treatment using activated alumina or reverse osmosis.

Barium is a lustrous, machinable metal which exists in nature only in ores containing mixtures of elements. It is used in making a wide variety of electronic components, in metal alloys, bleaches, dyes, fireworks, ceramics and glass. In particular, it is used in well drilling operations where it is directly released into the ground. Removed by ion exchange, reverse osmosis, lime softening, and electrodialysis.

Beryllium is an inorganic metallic element in the periodic table. Because it is an element, it does not degrade nor can it be destroyed. Compounds of beryllium are either white or colorless and do not have a particular smell. Beryllium naturally enters surface water and ground water through the weathering of rocks and soils or from industrial wastewater discharges. The major source of environmental releases from human activities are coal and fuel oil combustion. Removed by activated alumina, coagulation/filtration, ion exchange, lime softening, reverse osmosis.

Bromate is a disinfectant byproduct. Bromate occurs when bromide in the water reacts with the disinfectant, ozone. Bromine is typically found in seawater at a concentration of about 65 ppm. It is a common industrial chemical and can be found in industrial waste, pesticides and biocide residue. It is typically only found at very low levels in fresh water, and its presence at concentrations greater than 0.05 ppm may indicate contamination by industrial waste or pesticides. Bromate and bromide are disinfection byproducts. Bromide is oxidized to bromate through disinfection with ozone. Removed by ion exchange, activated carbon, and reverse osmosis processes.

Cadmium is a toxic heavy metal found in natural deposits as ores containing other elements, but is more likely to occur due to corrosion of galvanized steel, in which it is a trace element. The greatest use of cadmium is primarily for metal plating and coating operations, including transportation equipment, machinery and baking enamels, photography, television phosphors. It is also used in nickel-cadmium and solar batteries and in pigments. Removed by ion exchange, iron adsorption, or reverse osmosis processes.

Chlorine is added to municipal water supplies as an antiseptic agent, typically at 2 ppm or less. Highly toxic to yeast. Carbon filtration removes chlorine. Chlorine and chloramines are very effective disinfectants that act by oxidizing the cellular membranes of microorganisms and rupturing the cell. Excess residual chlorine can lead to higher levels of disinfection byproducts that can be hazardous to health and generate off-flavors in beer. Medicinal chlorophenol compounds are one example of an off-flavor. Residual chlorine and chloramine should be removed before use in brewing. Brewers should be aware that additional removal steps may be occasionally required, such as activated carbon filtration or chemical neutralization. Chlorine will oxidize and destroy membrane filtration equipment.

Chromium is an odorless and tasteless metallic element. Chromium is found naturally in rocks, plants, soil and volcanic dust, humans and animals. The most common forms of chromium that occur in natural waters in the environment are trivalent chromium (chromium-3), and hexavalent chromium (chromium-6).
Chromium-3 is an essential human dietary element and occurs naturally in many vegetables, fruits, meats, grains and yeast. Chromium-6 occurs naturally in the environment from the erosion of natural chromium deposits but it can also be produced by industrial processes. Chromium compounds are very persistent in water as sediments.

Copper is a beneficial complexing agent at low concentration (~0.1 ppm) in wort.  Sulfides and other sulfurous compounds can be complexed out of the wort by copper.  The copper concentration should be kept below 1 ppm to avoid mutagenic effects to yeast and metallic flavor.  Historic brewing practices often used all copper boil kettles, so it appears unlikely that overdosing wort from copper contact will occur.  A modest area of exposed copper metal in contact with the wort during the brewing process is typically sufficient to provide beneficial copper contribution.  For instance, a couple of inches of copper tubing in a 5-gallon (19L) batch may be sufficient to produce a beneficial copper concentration in wort.  

Cyanide is a carbon-nitrogen chemical unit which combines with many organic and inorganic compounds. The most commonly used form, hydrogen cyanide, is mainly used to make the compounds needed to make nylon and other synthetic fibers and resins. Other cyanides are used as herbicides. Cyanides are occasionally found in drinking-water, primarily as a consequence of industrial contamination. Removed by ion exchange and activated carbon filtration.

Fluoride, a halogen like chlorine and iodine, can be found in many minerals. It is commonly added at 1.5-2.5 ppm to potable water to help provide protection against tooth cavities. Concentrations above 5 ppm can cause tooth brittleness and spots. Wastewater from glass, steel, and foundry operations can have much higher concentrations. Lime precipitation can drop high concentrations to 10-20 ppm. Other useful removal processes are reverse osmosis, granular activated carbon, and activated alumina.

Lead is a toxic metal that was used for many years in products found in and around homes. Even at low levels, lead may cause a range of health effects including behavioral problems and learning disabilities. The primary source of lead exposure is lead-based paint in older homes. Lead in drinking water can add to that exposure. The major sources of lead in drinking water are corrosion of household plumbing systems; and erosion of natural deposits. Lead enters the water (“leaches”) through contact with the plumbing. Lead leaches into water through corrosion – a dissolving or wearing away of metal caused by a chemical reaction between water and your plumbing.

Mercury is a liquid metal found in natural deposits such as ores containing other elements. The major sources of mercury in drinking water are erosion of natural deposits; discharge from refineries and factories; runoff from landfills; and runoff from croplands. Removed by coagulation/filtration, granular activated carbon, lime softening, and reverse osmosis.

Nickel is a dangerous human toxins and extremely powerful yeast growth inhibitors. Nickel is not normally present in water in high enough quantities to be problem-causing.

Potassium is a component of malt and it is contributed to wort.  The ionic potassium content of water has some effect on flavor, adding a ‘saltiness’ to the beer at elevated concentration (typical taste threshold around 100 ppm).  Potassium in the water at levels above 10 ppm are reported to inhibit certain enzymes.  Since potassium is contributed by the malt, there is little need to add more to brewing water. Potassium carbonate is popular in winemaking due to its ability to precipitate tartaric acid and neutralize excess acidity. However, typical beer wort does not have significant tartaric acid and its use in brewing is less appealing.

Selenium is a metal found in natural deposits as ores containing other elements. The greatest use of selenium compounds is in electronic and photocopier components, but they are also widely used in glass, pigments, rubber, metal alloys, textiles, petroleum, medical therapeutic agents, and photographic emulsions.

Thallium is a metal found in natural deposits such as ores containing other elements. The major sources of thallium in drinking water are leaching from ore-processing sites; and discharge from electronics, glass, and drug factories. Removed by activated alumina; ion exchange.

Tin is not very toxic, but is a powerful haze former. The most common reason is from tin leaching out of solder joints in equipment and plumbing.

Zinc is a yeast nutrient when present at very low concentrations of 0.1 to 0.2 ppm and that level should not exceed 0.5 ppm in wort.  Zinc is present in malt and zinc extraction is improved with lower mash pH.  When present at higher levels (>1 ppm), zinc becomes toxic to yeast and produces a metallic flavor.  Commercial yeast nutrient preparations typically provide zinc in their formulation.  Zinc chloride or zinc sulfate may be used to produce the desired zinc concentration in wort.  However, the dosing of those zinc salts is very low. For example, the dose of solid zinc sulfate heptahydrate is 1 gram per 10 barrels of ale or 1 gram per 20 barrels of lager. 

Minerals and Beer Styles

The historic beer styles that have developed around the world were sometimes the result of the water conditions present in that area.  Prior to the understanding, measurement, and ability to adjust water chemistry, beer styles evolved to suit the local water.  Typically, dark-colored beer styles developed in areas with high RA water and light-colored beer styles developed in areas with low RA water. 

Additionally, ions affecting beer flavor perception in the local water also influenced beer styles.  For instance, malty styles may be enhanced in areas with low sulfate concentrations while hoppy styles were enhanced in areas with elevated sulfate concentrations.

Examples of the ionic concentrations of water from various major brewing centers are shown in the table below.  There are a variety of literary sources that provide differing estimates of the appropriate ionic concentrations for these brewing waters.  For some of those literary sources, the quoted ionic concentrations are known to be incorrect since the indicated ionic balance could not exist at reasonable pH levels and the water profiles are not supported with factual laboratory data.  The concentrations shown in the table below have been researched and verified with historic and current references.  The profiles are also corrected where necessary to provide an appropriate ionic balance.  

The groundwater in Burton-on-Trent is the result of upwelling from the Mercia Mudstone (a gypsum-bearing formation) into the surficial Sand and Gravel aquifer where it mixes with groundwater supplied by rainfall infiltration and the nearby Trent River.  The more the brewers of the region utilized the shallow water source, the more the sulfate-laden upwelling was diluted by the rainwater and river water.  The amount of rainfall and the river level affected their local groundwater quality.

The local groundwater in Dortmund is very hard and mineralized.  The high hardness reduces RA and made it possible to brew pale beers with a minerally edge. Due to the mineralization, water is now piped in far from Dortmund.  The profile presented for Dortmund does produce a substantially minerally-tasting beer and brewers may want to moderate the sulfate and chloride content in practice.

Water quality in Dublin is highly dependent upon location within the city.  In the north and west parts of the city, drinking water is hard and alkaline from the River Liffey. But south of Dublin,  water comes from the Wicklow Mountains where the water is only lightly mineralized. Interestingly, Guinness’ St James Gate brewery was traditionally fed from the Wicklow Mountains and the tart character of their dry stout was developed with that water and not the hard, alkaline water found in the rest of Dublin.  While more alkaline water is typically used in stout and porter brewing, dry stouts are more authentic when brewed with Wicklow water which can be similar to RO water. 

As with many breweries, their water source was taken from the area immediately around the brewery. In the case of many Edinburgh breweries, the groundwater was somewhat hard and mineralized. Somewhat elevated sulfate content was typical and that helped malty beers from the area to present a pleasingly dry finish to that maltiness. Modern Edinburgh has outgrown the local water supply and water is now piped in from miles away.   

This is actually a tale of two cities, or more accurately, two water sources. The original water source for London was River Thames. It’s moderate hardness and alkalinity made it feasible to brew pale beers with it. Some say the original pale ales and IPAs were developed with that water. London’s real fame came from Porter brewing and that had to due to the advent of well drilling and the presence of soft, slightly salty, and alkaline groundwater below the city. The water has significant sodium, sulfate, and chloride. That water was suited for Porter brewing. While the Thames is still a source of London water, the groundwater below the city is now rarely used for brewing use due to pollution.

All of southern Bavaria has similar geology and water quality.  The limestone beneath Bavaria provides a hard and alkaline groundwater that is otherwise low in flavor ions such as sodium, sulfate, and chloride. The high alkalinity and hardness of that raw water are somewhat suited to brewing the dark styles originally produced in the city, but it was difficult to produce the lighter colored beers that the city became known for.  Brewers developed forms of alkalinity reduction to make their water suitable for pale beers.

Located in an area with little limestone or dolomite contact, the surface water and groundwater tends to have little mineralization. While the raw water has low mineralization, its reported that breweries such as Pilsner Urquell add a small amount of gypsum to their brewing liquor.

Groundwater from wells along the Danube River supply the city. With Vienna being downstream of Bavaria, the water quality somewhat mirrors the quality of Munich and that region.

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