Lesson 4 - Brewing Water Composition and Impact
This lesson deals with the influences of water composition on brewing equipment, the brewing process and beer quality. It will cover the positive and negative impacts that the various compounds found in water have on beer. We will explore the recommended water specifications for brewing key beer styles. We will also examine how to correct levels of some of the key salts within water.
Base-line Product Water
Product water tends to be of higher quality than standard potable water. This is because some of the chemicals found in standard water will negatively affect the brewing process, equipment and final beer quality.
In the previous lesson, we explored the maximum concentration of the microbiological and chemical parameters allowed in order to meet legal potable water standards (using the UK standards as an example). We have now updated this table which shows recommended levels for product water as compared to the potable water standard.
Table: Microbiological parameters
|
Constituent |
Maximum Concentration for potable standards (mg/L) |
Suggested level for base product water (mg/L) |
Positive attributes |
Negative attributes |
|
Aluminium |
0.2 |
< 0.2 |
|
Can be problematic in cooling water systems. Poisonous metal |
|
Arsenic |
0.01 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc). Poisonous metal. |
|
Boron |
1.0 |
< 1.0 |
- |
- |
|
Bromate |
0.01 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc). |
|
Cadmium |
0.005 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Toxic. |
|
Chromium |
0.05 |
< 0.05 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Carcinogenic. |
|
Copper |
2.0 |
< 1 |
Small amounts can reduce sulphides in wort and H2S in beer.
Essential nutrient for yeast. |
Inhibits enzymes and becomes toxic to yeast at levels > 10 mg/L.
Oxidation catalyst in beer, affecting flavour and colloidal stability. |
|
Cyanide |
0.05 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Toxin. |
|
Fluoride |
1.5 |
0 |
Commonly added to drinking water to improve teeth health.
|
Indicates contamination from environment (e.g. mining, farming, industry, soil etc). |
|
Chlorine |
4 |
0 |
Inhibits the growth of microorganisms |
Can cause off-flavours in beer (such as chlorophenol) and be toxic to yeast in high levels.
Can oxidise and damage membrane filtration equipment. |
|
Iron |
0.2 |
0 |
|
Can cause incomplete saccharification of wort.
Oxidation catalyst in beer affecting flavour and colloidal stability.
Discolouration of foam.
Can inhibit yeast and produces beers lacking body and insipid in flavour.
Can contribute a metallic flavour to beer.
Can lead to corrosion of stainless steel piping. |
|
Lead |
0.01 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
(Can be due to corrosion of pipes containing lead.) |
|
Manganese |
0.05 |
< 0.05 |
Can act as a co-factor to yeast enzymes. |
May inhibit fermentation at levels > 0.5 mg/L.
Can cause a number of similar problems to iron. |
|
Mercury |
0.001 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc) |
|
Nitrate |
50 |
< 10 |
|
> 10 mg/L may indicate contamination (e.g. agricultural run-off).
Nitrates can be reduced to nitrites by microorganisms.
Nitrate can also affect fermentation rates |
|
Nitrite |
0.5 |
< 0.1 |
|
Poisonous to yeast cells.
Can indicate contamination with wastewater. |
|
Odour |
< 1 at 25˚C |
< 1 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Odour can carry through to the final beer. |
|
Sodium |
200 |
0-50 |
< 150 mg/L Contributes to a full and sweet palate. |
> 150 mg/L contributes salty/sour and metallic notes. |
|
Taste |
< 1 at 25˚C |
< 1 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Off-flavours can carry through to the final beer. |
|
Tetrachloroethene and Trichloroethene |
0.01 |
0 |
|
Formed when organic material reacts with chlorine used for disinfection
Inky chemical off flavour
Toxic and possible carcinogen. |
|
Tetrachloromethane (THM) |
0.003 |
0 |
|
Formed when organic material reacts with chlorine used for disinfection
Inky chemical off flavour
Toxic and possible carcinogen. |
|
Trihalomethanes: Total |
0.1 |
0 |
|
Formed when organic material reacts with chlorine used for disinfection
Inky chemical off flavour
Toxic and possible carcinogen. |
|
Turbidity |
4 NTU (Nephelometric Turbidity Unit)
|
0-0.5 |
|
Poor beer clarity. |
|
pH |
6-8 |
6-7.5 |
Low pH increases extract yields, wort run-off rates and fermentability.
Low pH decreases the extraction of haze-causing polyphenols. |
Low pH decreases isomerisation of hop bittering compounds. |
Chemical parameters
|
Constituent |
Maximum Concentration for potable standards (mg/L) |
Suggested level for base product water (mg/L) |
Positive attributes |
Negative attributes |
|
Aluminium |
0.2 |
< 0.2 |
|
Can be problematic in cooling water systems. Poisonous metal |
|
Arsenic |
0.01 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc). Poisonous metal. |
|
Boron |
1.0 |
< 1.0 |
- |
- |
|
Bromate |
0.01 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc). |
|
Cadmium |
0.005 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Toxic. |
|
Chromium |
0.05 |
< 0.05 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Carcinogenic. |
|
Copper |
2.0 |
< 1 |
Small amounts can reduce sulphides in wort and
Essential nutrient for yeast. |
Inhibits enzymes and becomes toxic to yeast at levels > 10 mg/L.
Oxidation catalyst in beer, affecting flavour and colloidal stability. |
|
Cyanide |
0.05 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
Toxin. |
|
Fluoride |
1.5 |
0 |
Commonly added to drinking water to improve teeth health.
|
Indicates contamination from environment (e.g. mining, industry, soil etc). |
|
Iron |
0.2 |
0 |
|
Can cause incomplete saccharification of wort.
Oxidation catalyst in beer affecting flavour and colloidal stability.
Discolouration of foam.
Can inhibit yeast and produces beers lacking body and insipid in flavour.
Can contribute a metallic flavour to beer.
Can lead to corrosion of stainless steel piping. |
|
Lead |
0.01 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc).
(Can be due to corrosion of pipes containing lead.) |
|
Manganese |
0.05 |
< 0.05 |
Can act as a co-factor to yeast enzymes. |
May inhibit fermentation at levels > 0.5 mg/L.
Can cause a number of similar problems to iron. |
|
Mercury |
0.001 |
0 |
|
Indicates contamination from environment (e.g. mining, industry, soil etc) |
|
Nitrate |
50 |
< 10 |
|
> 10 mg/L may indicate contamination (e.g. agricultural run-off).
Nitrates can be reduced to nitrites by microorganisms.
Nitrate can also affect fermentation rates |
|
Nitrite |
0.5 |
< 0.1 |
|
Poisonous to yeast cells.
Can indicate contamination with waste water. |
|
Odour |
< 1 at 25˚C |
< 1 |
|
Indicates contamination from environment (e.g. mining, farming industry, soil etc).
Odour can carry through to the final beer. |
|
Sodium |
200 |
0-50 |
< 150 mg/L Contributes to a full and sweet palate. |
> 150 mg/L contributes salty/sour and metallic notes. |
|
Taste |
< 1 at 25˚C |
< 1 |
|
Indicates contamination from environment (e.g. mining, farming, industry, soil etc).
Off-flavours can carry through to the final beer. |
|
Tetrachloroethene and Trichloroethene |
0.01 |
0 |
|
Formed when organic material reacts with chlorine used for disinfection Inky chemical off flavour
Toxic and possible carcinogen. |
|
Tetrachloromethane |
0.003 |
0 |
|
Formed when organic material reacts with chlorine used for disinfection Inky chemical off flavour
Toxic and possible carcinogen. |
|
Trihalomethanes: (THM) Total |
0.1 |
0 |
|
Formed when organic material reacts with chlorine used for disinfection Inky chemical off flavour
Toxic and possible carcinogen. |
|
Turbidity |
4 NTU (Nephelometric Turbidity Unit) |
0-0.5 |
|
Poor beer clarity. |
|
pH |
6-8 |
6-7.5 |
Low pH increases extract yields, wort run-off rates and fermentability.
Low pH decreases the extraction of haze-causing polyphenols. |
Low pH decreases isomerisation of hop bittering compounds. |
in beer.It is important to note that water pH doesn’t always translate into mash and wort pH. As we saw in the last lesson, calcium and bicarbonate levels in the water determine mash and wort pH, not water pH.
This table shows that in most cases, the product water requires lower levels of the various chemicals. This is because they can all negatively affect the brewing process and/or the beer. Later in this lesson, we will cover the various water treatment options available to reduce these chemicals to the recommended levels. Before we do that, let us discuss the importance of the base product water’s mineral composition.