Water Hardness Flashcards
What contributes to the ‘hardness’ of water?
Certain minerals that dissolve in water
Hard water primarily contains salts of calcium and magnesium.
What is hard water characterized by?
High mineral (ion) content
Mainly consists of calcium and magnesium cations with various anions.
Define an ion.
An atom or group of atoms with a net positive (cation) or negative charge (anion)
What are the two types of water hardness?
Permanent hardness and temporary hardness
How is total hardness calculated?
Total hardness = permanent hardness + temporary hardness
What is permanent hardness?
Hardness that cannot be removed by boiling
Consists of non-carbonate salts like sulphates and chlorides.
What method is used to remove permanent hardness?
Ion exchange column
What is temporary hardness?
Hardness that can be removed by boiling
Involves carbonate or bicarbonate salts of calcium or magnesium.
How can temporary hardness be removed besides boiling?
By adding calcium hydroxide [Ca(OH)2]
How can the hardness of water be tested quickly?
Using soap in water
True or False: Hard water forms a good lather with soap.
False
Hard water collapses soap lather due to insoluble salts.
What problems does hard water cause?
Scaling in pipes and reduced heat transfer efficiencies
How do minerals in hard water affect pH?
Temporary hardness raises pH, permanent hardness lowers pH
What happens when boiling water with temporary hardness?
Calcium carbonate (CaCO3) precipitates out, releasing CO2
What is the effect of temporary hardness on wort?
Can lead to poor saccharification and dark worts
How does permanent hardness affect mash pH?
It reduces pH due to interaction with phosphates from malt
What is the European Brewery Convention’s definition of water hardness?
Defined in degrees of hardness by country
In Germany, what does one degree of hardness correspond to?
10 mg CaO/L
What is the equivalent for calcium ions?
20
Calculated as atomic weight divided by valence.
What is the equivalent for magnesium ions?
12.1
What is one method to calculate total hardness as CaCO3?
Total Hardness as CaCO3 = (2.5 x Ca2+) + (4.12 x Mg2+)
Fill in the blank: Total hardness is expressed as mg of _______.
CaCO3
What is the molar mass of CaCO3 used for calculations?
100.1 g/ml
What does the titration method for measuring total hardness involve?
Using EDTA to bind and precipitate calcium or magnesium
