Lesson 5 - Brewing Water Composition and Impact SAQ
This lesson provides the opportunity for you to test yourself on the material covered in Lesson 4 (Brewing Water Composition and Impact) and determine the level to which you have attained the expected outcomes.
Suggested Response - Q5
**You have been asked to design a water specification for a pale lager. You have been provided with the following parameters:
Microbiological
Copper
Iron
Manganese
Nitrate
Sodium
Alkalinity
Calcium
Chlorine
Chloride
Magnesium
Sulphate
Zinc
Provide suggested levels and reasons for each of the parameters listed.
Response:
|
Parameter |
Level (mg/L) |
Reason |
|
Microbiological |
0 |
Microbiological infection can cause flavour taints and colloidal instability. |
|
Copper |
< 1 |
Maintain very low levels to help reduce any H2S or SO2, and as a yeast nutrient. Nothing higher, as it can become toxic to yeast and be an oxidation catalyst. |
|
Iron |
0 |
Iron inhibits yeast, causing incomplete saccharification and the beer to lack body and flavour. Iron also discolours foam and causes a metallic flavour. It is an oxidation catalyst affecting both colloidal and flavour stability. |
|
Manganese |
< 0.05 |
Low levels are a co-factor to yeast enzymes |
|
Nitrate |
0 |
Nitrate can become nitrite, which is toxic to yeast. |
|
Sodium |
0-25 |
At these levels, the sodium may contribute to a full and low-level sweet palate. |
|
Alkalinity |
0-40 |
Lower levels of bicarbonate prevent the pH of the mash and wort being too high, You want the water to be soft. |
|
Calcium |
50-75 |
Helps ensure correct mash pH and aids yeast flocculation and beer stability. |
|
Chlorine |
0 |
Prevents chlorophenol flavours, can be toxic to yeast. |
|
Chloride |
50-100 |
May provide fullness and sweetness in order to balance bitterness. |
|
Magnesium |
0-15 |
Low levels, to act as a co-factor to yeast. |
|
Sulphate |
50-100 |
Levels might support bitterness and dryness. Ratio with chloride at 1:1 may give a balanced beer. |
|
Zinc |
< 0.5 |
Yeast nutrient at these levels. |