On January 9, 1868, in Denmark, Søren Peter Lauritz Sørensen was born , a chemist who came to work as a director in 1900 in the laboratory of the Carlsberg brewery in Copenhagen. In this laboratory, from its studies and experiments, the concept of pH measurement emerged.

That's right! This topic so discussed in the brewery was initially disseminated within a brewery.

Water, the primary ingredient in beer, beer ads have always promised refreshing beer made from “sky blue waters,” “Rocky Mountain Springs,” or even “water from when the earth was pure.”

But does it matter where the water comes from?

Unfortunately there is no simple answer; it’s both yes and no.

What id pH?

In chemistry, pH (denoting 'potential of hydrogen' or 'power of hydrogen') is a scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions (solutions with higher concentrations of H⁺ ions) are measured to have lower pH values than basic or alkaline solutions.

The pH is a scale that serves to measure the acidity/alkalinity of a medium or, in our case, beer in its various stages of production. This numerical scale is represented from 0 to 14, with 7 corresponding to the neutral medium, less than 7 to the acidic medium and greater than 7 to a basic or alkaline medium.

The pH scale is logarithmic and inversely indicates the concentration of hydrogen ions in the solution. This is because the formula used to calculate pH approximates the negative of the base 10 logarithm of the molar concentration of hydrogen ions in the solution. More precisely, pH is the negative of the base 10 logarithm of the activity of the H⁺ ion.

At 25 °C, solutions with a pH less than 7 are acidic, and solutions with a pH greater than 7 are basic. Solutions with a pH of 7 at this temperature are neutral (e.g. pure water). The neutral value of the pH depends on the temperature, being lower than 7 if the temperature increases. The pH value can be less than 0 for very strong acids, or greater than 14 for very strong bases.

Remembering... This is a logarithmic scale, it means, the variation from pH 6 to pH 5, for example, corresponds to a variation of 10x, with this, pH 5 is 10x more acidic than pH 6, and 100x more acid than pH 7, and so on...

We must be careful because a small variation in the scale represents big changes in reality.

The pH is determined, in practice, using pH meters or the famous tapes that change the color.

The role of water in beer production

Water, in relation to quantity , is the most important ingredient in the brewing process, because approximately 95% of the beer's weight is water. With that, our brewing water deserves special care in the production process.

The sources of water chosen for making beer are, in general, two: mineral water of gallon or water "of the tap". What matters to the brewer in relation to the characteristics of the water are only the aesthetic aspects of the minerals .

The main function of minerals is to adjust the pH of the wort. In addition, minerals will also be responsible for contributing to the enhancement of flavors present in beer,

The pH of water

The pH of the water, in general, remains very constant, around 7. What is important to know about the pH of the water is that the pH of the water remains constant due to the amount of carbonates dissolved in it. This property of water is called a buffer . The buffer makes it difficult to change the pH of the water.

If, for example, an H+ ion (or a drop of acid) is added to this medium, this ion will react with the carbonate in the buffer maintaining the amount (number) of H+ ions in the medium, that is, also keeping the pH constant .

So, the greater the amount of carbonates (alkalinity), the greater the water's ability to not let the pH drop.

With this, it is expected that a very alkaline water, with a large amount of bicarbonate, and consequently a large amount of calcium carbonate, or magnesium, will have a high buffering capacity , being very resistant to pH changes.

Water + malt:

Finally, we will now understand the pH adjustment of the wort mentioned above.

Malt grains have a high concentration of phosphates . When we add water to the malt, what happens is the reaction of these phosphates with the minerals present in the water, resulting in the release of H + ions, that is, there is a tendency for the must to become acidic.

To make beer, this acidification of the wort is very desirable! If the water has a large amount of carbonates, the pH will not decrease.

When the carbonate is completely consumed in the reaction, the pH will decrease. Ideally, the mash pH for all beers should be between 5.2 to 5.5.

However, if the water is too alkaline it will have a high capacity to resist the pH change and, therefore, the pH of the wort will be above 5.5.

pH per process:

• Simple brewing: pH 5,2 - 5,4

• Brassing by decoction or with a “grist with few enzymes”: pH 5,4 (not above 5,6)

• Wash: Desirable pH: below 7,0, ideal: below 6,0 (but not below 5,5)

• Boil: pH 5,2

Historical perspective

Water’s geographical origins matters and is most responsible for many contemporary beer styles. Most famous is the water in England’s Burton-on-Trent region, the birthplace of pale ale and India pale ale. Once a spa town where the nobility and elite came to “take the healing waters,” Burton-on-Trent’s healthful waters gained acclaim in the 19th Century for its brewing properties. The same high sulphate, magnesium and calcium and low levels of sodium and bicarbonates that had made the waters a comforting bath were also fantastic for brewing beer.

Without getting too technical, the ionic profile of Burton water accentuates hop bitterness and creates the dry, minerally profile of traditional bitters, pale ales and IPAs. Nineteenth century writers described Burton as “[t]he one spot in the world where the well-water is so obviously intended by nature for kindly union with those fruits of the earth, to give beer incomparable.”

Other towns equally famous in beer circles for their waters and the beers they created include Dublin, whose water is high in carbonates and well suited to brewing stouts and dark porters. Guinness anyone? Here the hard water and high alkalinity make it nearly impossible to brew a decent pale ale, but dark malts, especially the black patent and other black malts used in the creation of stouts, add acidity back to the mash water, lowering its ph and making conversion possible. The resultant beer was a dark, rich, slightly acidic with a wonderfully rounded maltiness, difficult to match anywhere else in the world and made Arthur Guinness a household name.

On the other end of the hardness scale are the soft waters in cities like Pilsen (Plzen) in the Czech Republic, renowned for the beer that bears that city’s name. The softness of the water in Pilsen allowed for the creation of a light beer with a greater intensity of malt flavor while still maintaining a rich, smooth and round palate.

Dortmund in Western Germany has water similar to Burton, but brewers decarbonated it using slaked lime to create the perfect water profile for Dortmunder Export, a pale, moderately bitter, but bright and dry lager (technically a golden helles) that was particularly popular in the United States with returning vets from WWII, but it unfortunately lost popularity to pale American lagers (Bud, Miller et al) in the ’50s and ’60s.

Those German brewers were on to something when they decarbonated water from the Dort River. Their manipulation of local waters illustrates that from a technical standpoint a region’s water makeup doesn’t matter. Indeed, like the German brewers in Dortmund, nearly every craft brewer often alters his water supply, starting with filters and adding chemical additions to their brewing water to match or mimic the specific region’s water profile that’s suitable for the style that they are producing.

Whether the brewery’s water may come from an artesian well, or a mountain spring or a municipal tap, it will be filtered at the very minimum through an activated charcoal filter, or through a reverse osmosis/deionization filter, which leaves the brewer with a neutral canvas that can be built with the addition of minerals and salts to match any water profile from around the world. In that way, water chemistry simply doesn’t matter.

Well, that may be a bit of an overstatement, the manipulation of water involves a bit more expense and expertise and is often outside the capital investment of many startup brewers. Thus, most small breweries will use minimal manipulation (simple filtering for chlorines and heavy metals or deoxygenation) and match their initial beer portfolios to their local water source. Others see water as part of a brewery’s terroir; they simply believe their local water supply is part of their craft and will work with it making beers that are a distinct reflection of the water they have access to. Still others argue that contemporary brewers will never be able to accurately match these historic waters and the beers they create, while close to the originals, will never be quite the same and thus water’s geographic origins remain important to the creation of regional beer styles.

It’s clear that water plays a huge role in the beer we drink. If you’d like to know more about brewing water and water’s effect on beer I’d suggest picking up a copy of “Water: A Comprehensive Guide for Brewers,” by John Palmer and Colin Kominski.