The Importance of Water Chemistry in Beer & Brewing
Beer is a composition of many elements and ingredients, but in large part, it is mostly water i.e. roughly about 90% - 95% of beer consists of water and the minerals it contains bring more than flavour to the alcobev.
Water is also called ‘liquor’ when it is associated with brewing. The importance of water is that the composition of chemical elements creates flavour and reacts differently during the brewing process.
As water travels and flows through many places over a span of time, along the way, it comes in contact with rocks, stones, soils and dissolves various minerals which consist of ions. All of which are chemically active and important for brewing beer. Minerals such as Calcium Carbonate, Calcium Sulphate and Sodium Chloride are typical examples, although there are many more. For example whenever the water table sits below limestone rock, it acquires Calcium Carbonates and the water profile is altered with the water becoming hard in texture, depositing, what is referred to as “Lime Scale” on frequently used appliances for boiling water e.g. catering urns and kettles.
The diagram above outlines typical minor trace elements found in drinking water, to which can also be added: Bicarbonate, Iron, Potassium and Zinc.
All good brewers know the importance of water in the brewing process. An understanding of the basic chemistry and how water influences the process is critical to delivering authentic beers of character. It eases the brewing process through to the final product, minimises waste and keeps the yeast healthy.
Calcium (Ca) and Magnesium (Mg) being alkaline ions have an impact on the alkalinity of water. However, their impact on the alkalinity of water in relation to brewing beer is marginal, if at all. They play a far greater role in mash enzyme activity, at the beginning of the brewing process, along with protein and yeast flocculation and pH regulation. When we talk about alkalinity, we refer to the abundance of carbonate and bicarbonate ions expressed as calcium carbonate CaCO3.
When there is a very high level of CaCO3 in the source water being used for brewing, i.e. greater than 100 ppm, it needs to be softened to allow the normal processes of brewing to take place at the correct pH. The high temperature in the hot liquor tank (HLT) disassociates the dissolved CaCO3 to Ca2+ and CO32- ions because the bonding is not strong (remember your chemistry of divalent bonding!).
When cool again, the ions recombine and often come out of solution as limescale. This is temporary softening like in a kettle or boiler. This often contains salts of sulphate and brewers often add a softening solution.
What does pH level mean in water?
pH is a measure of how acidic/basic water is. The letters pH stand for potential of hydrogen, since pH is effectively a measure of the concentration of hydrogen ions (that is, protons) in a substance. The range goes from 0 to 14, with 7 being neutral and where water should ideally be, though this can vary between 6.5 - 8.5 on the scale. A pH of less than 7 indicates acidity, whereas a pH of greater than 7 indicates a base. pH is really a measure of the relative amount of free hydrogen and hydroxyl ions in the water.
Beer brewing relies on pH levels to determine the acidity – of which many are acidic, with an average of 4.0-4.4. Beer should be slightly acidic, as a high pH can lead to harsh flavours and incomplete enzymatic conversion of the mash. During beer production, measuring the pH is important at every stage of the brewing process, from the initial water to create the mash, to the finished beer product.
The concept of pH was first invented by Danish chemist S.P.L Sorensen by experimenting with beer at the Carlsberg Laboratory in Copenhagen in 1909… Therefore it is all thanks to brewing beer, that the helpful pH scale in chemistry was born!
Is Beer Acidic or Alkaline?
The pH level of beer indicates the alkalinity or acidity of the product. While most food and drinks we consume daily have a neutral pH level of 7.0, beer pH levels can go as low as 3.0!
However, the pH scale is not just a number. Measuring the pH of beer tells you the concentration of hydrogen ions. To put this into context, if the hydrogen ion concentration increases inside the beer, the beer will be more acidic. Whereas, if the number of ions decreases, the beer will be more alkaline, or caustic.
The pH of beer also affects the following:
The beer’s appearance.
The taste (hop bitterness).
Beer foam stability.
Extract potential.
Hot-break formation.
Hop oil extraction.
The average pH value of beer is usually around 4.0 Despite 4.0 being the ‘typical’ pH value of beer, the pH value depends on the type of beer.. For example, an ale is more likely to have a higher pH level than lager or stout.
The list below provides the typical pH values for various beer types based on the most to least acidic:
The Importance of pH in the Beer Brewing Process
Knowing the pH of the finished beer is essential, but you need to start monitoring the pH level from the start of the brewing process. This means starting with the water used for the mash, which is the initial stage of the brewing process, where crushed grains are mixed with water to form a mash, or porridge like mixture.
The pH level of the mash is the same despite which type of beer is being brewed and the pH range should be between 5.2 and 5.6 when the water and grains are mixed, but always aiming for the lower end of this range to produce good-quality mash.
The pH of beer at this stage is critical so that the wort will quickly convert to beer later on. But, sometimes the pH of beer requires attention and there may be times when you will need to alter the pH of your beer during the mash process.
Examples of Water Profiles by Region
Different renowned beer brewing regions around the world have very different water profiles and rely heavily on the regional water profile.
Burton on Trent
The water from this part of the UK contains a high amount of calcium sulphates, gypsum, which makes it an ideal choice for brewing crisp, dry and very hoppy beers, such as IPA's.
Dortmund
The historic water profile of the Dortmund region, has high levels of carbonates, chlorides and sulphates, which provide beer types such as Dortmund or Helles Exportbier with additional bitterness.
Dublin
With a high level of alkaline, the water profile is well suited for brewing darker beers like Irish Dry Stouts.
Munich
Water in the Munich region is somewhat similar to Dublin, in that there is a high alkaline content and brewing darker lagers such as Munich Dunkel or Schwarzbier is assisted by this.
Pilsen
The Czech town of Pilsen (Plzen) has an extremely soft water profile, due to the low mineral content. Which makes it ideal for the brewing of the most iconic lager styles, such as Bohemian Pilsner and Czech Premium Pale Lager.
Welsh Water
The Brecon Beacons/Bannau Brycheiniog supply almost half of the drinking water used in Wale, which is why it is referred to as a Mega Catchment Area for water.
The water resource position of Welsh Water's area of supply is relatively strong. With around 95% of water resources originating as surface water either from reservoir storage or river abstractions, with negligible dependence on groundwater supplies. Annual rainfall is 55.9in, with a minimum of 3in in April and a maximum of 6.2in in December.
The overall height of the area and relative proximity to the Atlantic ocean make the Brecon Beacons an ideal catchment area for clean rainfall.
Water Hardness or Softness
Water is naturally soft when it falls from the sky and gains its hardness after coming into contact with the ground. If rainwater lands in an area with porous rock, such as limestone, the water collects and dissolves minerals such as calcium (Ca) and magnesium (Ma), as it permeates the bed rock, gaining hardness.
As previously stated water usually makes up 90–96% of beer, the rest being mainly alcohol and compounds for colour, body and flavouring. This high percentage of water has a large impact on the flavour of the beer and historically has led to certain types being predominantly brewed in specific areas.
Different types of beer can be brewed depending on the hardness of the water. Hard water is best suited to the fuller bodied, stout type beers such as Guinness, whereas soft water is better for crisper, lighter, hoppy beers such as pale ales, lager and pilsners.
Water hardness and softness is measured in parts per million (PPM) and how many particles of hardness are dissolved in the water per million particles gives a rating.
This rating has been developed over time to the categories shown in the adjacent table.
The water that we use for brewing falls into the category of soft (0-50ppm) to moderately soft (51-100ppm) and we are pleased to have access to such fresh, soft water for our beers and not requiring the addition of softening chemicals.
If you would like to learn more about craft brewing, read our other blog articles on beer types, grain, hop and yeast selection.
References: