Water report

From Brewing Forward
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See Water.

We are most interested in calcium, magnesium, alkalinity, sodium, chloride, and sulfate.

MCL stands for "Maximum Contaminant Level", and they are just provided as a reference to safety standards. For our purposes we can ignore these values unless of course the tested value is above the MCL, in which case the water is not even safe to drink.

Nitrate (NO3-) should to be limited to less than 25 ppm, as otherwise the fermentation may be adversely affected.[1]

The concentration of nitrate in water is restricted to less than 50 mg/L; this can still consti- tute a risk due to the potential formation of nonvolatile nitrosamines (suspected carcinogens). The mechanism involves the reduction of nitrate to nitrite (by bacterial nitrate reductase activity) and the chemical reaction of nitrite with any wort and beer nitrogen compounds, such as amines.39 Water represents the major source of nitrate in beer; the brewing process can only add to the nitrate content of the water used for brewing. Whole hops can contain up to 1.0% w/w nitrate.39 Reduction of the nitrate content to less than 10 mg/L may be desirable, and maintenance of high hygiene standards will reduce risk of bacterial contamination with nitrate reductase capability, especially yeast handling procedures.39 The presence of nitrite in water indicates contamination by wastewater. The concentration is restricted to less than 0.5 mg/L.2[2]

Silica (SiO2) is linked to the occurrence of turbidity in the beer and hence should not exceed 25–40 ppm.[1]

Trihalomethanes are byproducts from chlorination and hence are often found when domestic water is used as a water source for supplying a brewery. As THMs are regarded as carcinogenic agents, their concentration should be limited to <10 ppb.[1]

"Hardness" (the number of bivalent metal ions like calcium and magnesium) and total alkalinity are often both expressed "as CaCO3" so that the levels of these types of ions can be easily compared. This is important for the deeper chemistry theory involved in predicting mash and boil pH. Fortunately, brewers who understand these interactions have designed software for us, so it's not exactly necessary for the average brewer to understand the theory behind it.

Fluoride has no adverse effects on fermentation at concentrations below 10 mg /l.2[2]

Silicate can be extracted from malt by sparging at a high pH.30 It is associated with Ca2+ and Mg2+ and may cause haze in the beer and scaling of vessels and mains.2[2]

in a water report, chlorine is typically labeled as "free chlorine" and total chlorine is "residual chlorine".[3]

Analysis should ideally also be carried out over at least a one-year period to determine seasonal fluctuations.[4]


Important water analysis parameters:[4] Smell Taste Colour Turbidity Temperature Conductivity KMnO4 consumption Fe Mn As NH4 Residual alkalinity Na Ca Mg HCO3 Cl SO4 NO3 SiO2 NO2 THMs

Definition of hardness units:[4] 1ÎF = 10 mg CaCO 3 /l 1ÎG = 10 mg CaO/l 1 meq/l = 50 ppm as CaCO 3

For a water composition to be valid, the sums of anion and cation charges should be equal (with a small margin of error). The easiest way to evaluate this is by converting the concentrations to milliequivalents per liter.[3]

Turbidity (NTU) 0.0–0.5 is the desired level for brew water[1]

Transition metals (most importantly iron, copper, and manganese) catalyze oxidation reactions, and therefore their levels should be as low as possible.

Heavy metals, such as lead and tin, should also be low because they are toxic to humans and can have negative effects on fermentation and clarity.[2]

References[edit]

  1. a b c d Eumann M, Schildbach S. 125th Anniversary review: Water sources and treatment in brewing. J Inst Brew. 2012;118:12–21.
  2. a b c d Taylor DG. Water. In: Stewart GG, Russell I, Anstruther A, eds. Handbook of Brewing. 3rd ed. CRC Press; 2017.
  3. a b Palmer, J. and Kaminski, C. Water: A Comprehensive Guide for Brewers. Brewers Publications, 2013.
  4. a b c Eumann M. Chapter 9: Water in brewing. In: Bamforth CW, ed. Brewing: New Technologies. Woodhead Publishing; 2006:183–207.