Most people do not realize how complex natural water is. Its composition may be different not only depending on a region or a country but also depending on the time of day in the same location. The word composition here does not describe the atomic structure of water itself but refers to the amount of minerals, gasses, salts and other substances such as traces of metals and chemicals.
We typically think about water as having no taste, but this is simply not true. Water does have taste and it is the nature of the presence of the above-mentioned substances that makes water taste “good” or “bad.”
There are three basic properties of water that matter for baking. They are chlorination, hardness, and alkalinity. All of these properties have an influence on the performance of dough.
Hard water and soft water
The hardness of water depends on how much calcium salts and magnesium salts it contains. Typically, non-distilled water has many salts in it, including calcium bicarbonate, calcium sulfate, magnesium chloride and others. The amount of calcium carbonate serves as the sum for all other salts. It is measured in parts per million and determines the hardness of water.
Levels of water hardness expressed in parts per million (PPM) of calcium carbonate
0-50 PPM: soft water
50 – 100 PPM: medium water
100 – 200 PPM: hard water
200+ PPM: very hard water
Very soft water produces doughs that are slack and sticky because it lacks the minerals that enhance the production of gluten in the flour. If you are using soft water, you can add salt to the dough to improve its structure.
Hard water helps yeasts become more active and makes gluten stronger. Water with medium softness works best for the development of gluten. Very hard water increases gluten fermentation time. If you need to decrease this time, you can add more yeast to the flour.
Alkalinity and acidity
The measure of alkalinity and acidity is pH. This abbreviation comes from French words for hydrogen power. pH has a scale from 0 to 14. pH of 0 means extremely strong acidity and pH of 14 means extreme alkalinity.
Pure distilled water is neutral, but natural water has various degrees of acidity and alkalinity. Yeasts prefer acidic environments, which is why they ferment better in slightly acidic water.