Water Alkalinity Flashcards
What affects water alkalinity?
The carbonate and bicarbonate concentration
High levels increase mash pH.
How is total alkalinity defined?
The amount of strong acid required to convert the carbonate and bicarbonate in the sample to CO2 at a pH of 4.4.
How can total alkalinity be estimated?
By titrating 100 mL of water with 0.1 M HCl to pH 4.4 using indicators like bromocresol green or methyl orange.
What is alkalinity expressed as?
mg of CaCO3, where 1 mL of 0.1 M HCl is equivalent to 5 mg of CaCO3.
Who is responsible for the concept of residual alkalinity?
Paul Kolbach.
What happens when calcium and magnesium react with phosphate compounds in the mash?
They release H+ ions that change bicarbonate ions to carbonic acid.
What is residual alkalinity (RA)?
Any alkalinity (bicarbonate) that remains after the reaction with malt phosphate.
How is an equivalent defined?
The atomic or molecular weight of an ion divided by the valence of the ion.
What is the equivalent for calcium ions (Ca2+)?
20.
What is the formula to calculate residual alkalinity (RA)?
RA = Alkalinity – [ (Ca / 3.5) + (Mg / 7) ]
How is total alkalinity typically reported?
As mg/L as CaCO3.
What are the equivalents for calcium, magnesium, and calcium carbonate?
- Calcium (Ca2+): 20
- Magnesium (Mg2+): 12.1
- Calcium carbonate: 50
What is the RA calculation using bicarbonate concentration?
RA = alkalinity (0.83 x HCO3- mg/L) – [ (Ca / 1.4) + (Mg / 1.7) ]
Fill in the blank: The residual alkalinity of water increases in line with ______ concentration.
carbonate and bicarbonate ion
True or False: A positive residual alkalinity will lower mash pH.
False.
What effect do darker malts have on mash pH?
They tend to be more acidic.
What does a negative residual alkalinity indicate?
It will lower the mash pH.
What is the typical source of raw water for brewing?
Surface and ground waters.
What happens to raw water in a water treatment plant?
It removes organic and particulate matter and disinfects the water.
Can we adjust water hardness and alkalinity in brewing?
Yes.
Is there only one brewing water specification?
No, different beers benefit from different mineral levels.
