Water is to beer what oxygen is to human beings. Did you know that beer is made up of around 90% to 95% water? But that’s not all. It takes an input of about seven to ten gallons of water for a one-gallon beer output. So, it is only reasonable that brewers would want to understand the chemistry behind making the best beer that they can and how the different elements in water and its pH will interact to give the taste in the final product.
What is pH?
pH, as commonly understood, stands for the power of hydrogen. This acronym doesn’t give us much information on what exactly it is, so let’s dive in a little deeper. The pH indicates how acidic or basic a solution is by measuring the concentration of hydrogen ions. Pure water has a pH of around 7 at a temperature of 25 degrees, and this can fluctuate based on temperature and gases in the atmosphere. If carbon dioxide gas, for instance, reacts with water, it lowers the pH to about 5.2 as the resulting reaction produces carbonic acid.
Ions and their effect on Mash pH
The concentration of ions (calcium, chloride, sulfate, sodium, magnesium, bicarbonate, and carbonate) in water can vary depending on your location. Water from high up in the mountains will have a very low if any, mineral content. But in a river lower down, water will be mineral rich as it is slower and has had time to interact with soil and rock.
The kind and concentrations of ions present have an impact on the flavor or taste of the wort as well as the pH of the mash, which is a mixture of crushed grains and water, giving a porridge-like consistency. An ideal mash pH range is 5.2 to 5.4, and it is highly dependent on the water’s chemical composition. If water is even slightly alkaline, the pH range can be pushed above ideal. Below are the effects of different ions on the mash and beer:
Calcium and Magnesium
Calcium plays a critical role in lowering mash pH to the acceptable range and determines hardness. It’s also good for clarity, stability, and flavor of the end product. Ideally, calcium concentration in water should be anywhere between 50 to 150 ppm.
However, it should be balanced with low levels of carbonate and bicarbonate ions. Magnesium also plays a similar role to calcium, but it doesn’t beat calcium. Its role is more pronounced in the fermentation stage during yeast metabolism.
Sodium has negligible impact on water at lower concentrations, but as soon as the concentration goes above 100 ppm, the beer starts to taste metallic, like a mineral, or like seawater. The pairing of sodium with other ions is important. Sodium with chloride gives the beer a sweet and pleasant taste, but when sodium is paired with sulfate, the taste becomes rather harsh and unpleasant.
Carbonate and Bicarbonate
The alkalinity of water depends on the concentration of carbonate and bicarbonate ions as they raise the pH of not only the mash but of the beer itself.
The sulfate ion enhances the bitter taste from the hops at low levels and makes the beer crisp and dry. However, if used excessively, the beer will be harsh and salty. Since it has low alkalinity, it doesn’t affect the overall pH of the mash or the beer. Hoppier beers like the American IPA or the American Pale Ale can be made by adding calcium sulfate or gypsum to water. These beers taste bitter, drier, and crispier.
Chloride ions add sweetness to the beer and make it seem fuller, thus making it completely opposite to the sulfate ion. The chloride-sulfate ratio will tell you whether the beer will be dry and bitter or have a maltier taste. Oktoberfest and Brown Ale are examples of malty beers made with the addition of calcium chloride to water.
The importance of maintaining an ideal Mash pH
Mash pH is influenced by two main factors, which are malt and water. Darker malts make the mash more acidic. As far as water is concerned, there are two main types, hard water and soft water. While hard water increases the alkalinity of the mash, soft water does the opposite. It makes it more acidic.
The most favorable mash pH is close to 5.2, which helps achieve the following:
- Increase in Enzymatic Activity
Amylases are important enzymes in the mash that work optimally at this pH and convert grain starch to sugar. The optimal pH at room temperature for alpha-amylase is 5.3, and for beta-amylase is between the range of 5.1 and 5.3. But, of course, mash temperature is different, and at that temperature, the optimal pH for the former is 5.7 and the latter in the range of 5.4 to 5.6. This change is due to a pH shift in the heated mash.
- Decrease in Tannin Extraction
Tannins are chemicals found in hops and husks, and if present excessively, they can lead to bitterness. High temperatures and pH (5.8 or above) can lead to greater tannin solubility in the wort. But considering that mash pH is lower than that, tannins dissolve much slower in the wort.
- Increase in Protein and Polyphenol Haze
The hazy beer trend is on the rise, and it turns out that the pH of the mash and the wort plays a crucial role in determining how much precipitation will occur. A pH of around 4 to 5.5 is ideal for the development of a protein haze.
Water Analysis and Filtration
A water testing kit or your local municipality report will give you a list of all the different ions present in the water you’re using to make beer. Based on your preferences, you can change the concentration of these minerals by first purifying the water. Perhaps the best purification method is reverse osmosis, in which you filter out the water and remove ions and impurities. Once pure, you can add the minerals that you want to achieve the desired taste. With this method, around 95% to 99% of the dissolved ions are removed.
I am a passionate beer connoisseur with a deep appreciation for the art and science of brewing. With years of experience tasting and evaluating various beers, I love to share my opinions and insights with others and I am always eager to engage in lively discussions about my favorite beverage.