Brewing Product Water Final Treatment SAQ 2 Flashcards
What type of water is traditionally used to brew pilsner style beers?
Soft water
Pilsner style beers are known for their crisp and clean flavor, which is best achieved with soft water.
What is temporary hardness in water primarily caused by?
High levels of carbonate or bicarbonate
Temporary hardness can be reduced through various treatment methods.
What is one method to reduce water hardness by heating?
Heat water above 70-80˚C
This process converts bicarbonate to calcium carbonate, which precipitates out of solution.
What are the disadvantages of heating water to reduce hardness?
Energy intensive and releases CO2
CO2 must be vented out due to health and safety risks.
What is the reaction when calcium hydroxide is added to reduce water hardness?
Ca(HCO₃)₂ + Ca(OH)₂ → 2 CaCO₃ + 2 H₂O
This method is effective but requires downstream filtration.
What is a disadvantage of using cation exchangers for water hardness?
Requires additional plant and can be expensive
Ion exchange resins need to be regenerated with acids, which can be dangerous.
How does a weak acid cation (WAC) exchanger work?
Exchanges a hydrogen ion for calcium
Converts calcium bicarbonate into water and CO2.
What is the main function of a strong acid cation (SAC) exchanger?
Removes all types of hardness, including temporary and permanent
Exchanges sodium or hydrogen ions for cations.
True or False: A SAC exchanger is necessary if only temporary hardness is present.
False
It is likely unnecessary if only temporary hardness is the issue.
What is the purpose of removing chlorine from brewing water?
Chlorine can be toxic to yeast and cause off-flavours
Chlorine can also damage membrane filtration systems.
What is one method to dechlorinate water?
Activated carbon filtration
Activated carbon adsorbs chlorine through physical or chemical processes.
What are the effects of UV light in dechlorinating water?
Breaks molecular bonds of chlorine, yielding chloride and water
UV light also kills bacteria and viruses.
What is a chemical option for sterilising brewing product water?
Chlorine dioxide
It is a powerful oxidising agent, non-corrosive and non-toxic in solution.
How is chlorine dioxide produced?
When hydrochloric acid reacts with sodium chlorite
This reaction generates chlorine dioxide for water treatment.
What is ozonation and its effect on bacteria?
Ozone is injected into water to achieve bactericidal activity
Ozone oxidizes bacterial cell membranes effectively.
What are the advantages of using ozone for water treatment?
Unaffected by pH, does not form THMs, works rapidly
Ozone is effective in killing bacteria without residual effects.
