Lesson 3 - Water SAQ
This lesson allows you to test yourself on the material covered in the Water lesson and determine the level to which you have met the learning outcomes.
Suggested Response - Q1
* Explain the differences between the following:
a) Process water and product water
b) Permanent hardness and temporary hardness
c) Sedimentation, coagulation, and flocculation
d) Residual and non-residual sterilisation.
Response:
a) Process water is used for processes such as cleaning equipment and cooling wort. It normally has been softened to prevent scaling.
Product water is used in the product itself or in processes where this water could in some way enter the product. The quality requirements for this are often stricter than for potable water. It may also require a specific mineral composition, depending on the style of beer you are brewing.
b) Permanent hardness cannot be removed (precipitated out) by boiling. It consists of the non-carbonate salts such as sulphates, chlorides, and nitrates of calcium or magnesium. Permanent hardness is removed by using an ion exchange column.
Temporary hardness can be removed by boiling as the carbonate or bicarbonate salts of calcium or magnesium precipitate out. Another method to remove temporary hardness is to add calcium hydroxide, Ca(OH)2, which precipitates calcium and magnesium carbonates.
c) Sedimentation is the settling out of particles.
Coagulation is the neutralisation of particle charges, which allows them to move closer together.
Flocculation is the clumping together of particles into flocs that can settle out.
d) Sterilisation that provides residual protection stays active in the water, e.g. when chlorine and chlorine dioxide are dosed. Sterilisation that provides only point of use protection does not carry forward with the water, and is therefore known as non-residual sterilisation. UV sterilisation is an example of this.