Introduction and Water Quality Brewing Science Introduction and Water Quality

Water

Hydrogen Bonds

Chapter 2, Figure 2.2, Covalent and noncovalent bond energies

Water

Chapter 2, Figure 2.14, One unit of clathrate structure surrounding a hydrophobic molecule

Chapter 2, Figure 2.16a, Interactions of amphipathic molecules with water

Chapter 2, Figure 2.12, Hydration of ions in a solution

Dissolved Ions in Water Enthalpy of Hydration Mx+(g) + nH2O  Mx+(aq) As size of cation decreases or charge increases, enthalpy increases (stronger interactions)

Enthalpy of Hydration of Some Typical Ions (kJ/mol) Ion Hhyd Ion Hhyd Ion Hhyd H+ -1130 Al3+ -4665 Fe3+ -4430 -- Li+ -520 Be2+ -2494 F- -505 Na+ -406 Mg2+ -1921 Cl- -363 K+ -322 Ca2+ -1577 Br- -336 Rb+ -297 Sr2+ -1443 I- -295 Cs+ -276 Ba2+ -1305 ClO4- -238 Cr2+ -1904 Mn2+ -1841 Fe2+ -1946 Co2+ -1996 Ni2+ -2105 Cu2+ -2100 Zn2+ -2046 Cd2+ -1807 Hg2+ -1824

Hydrolysis of cations Metal ions in aqueous solution behave as Lewis acids [M(H2O)n]x+ + H2O  [M(H2O)n-1(OH)](x-1)+ + H3O+ Note the similarly to a typical acid ionization: HA + H2O  A- + H3O+

Analogous to a pKa

pH pH = -log[H+]

Acids

Ions in Brewing Important Cations Calcium (Ca+2) Contributes to permanent water hardness Interacts with malt phosphates which lowers pH during mashing and boiling Helps yeast flocculation and beer clarification Also aids protein coagulation during hot and cold breaks According to Dave Miller the optimum is 50-100 mg/l. Provided by Ken Woodson & the North Texas Home Brewers Association

Ions in Brewing Important Cations Magnesium (Mg+2) Contributes to permanent water hardness Lowers mash pH similar to Calcium, but not as effective Usually sufficient amount present in malt, so seldom have to add to brewing water. Good yeast nutrient at 10-20 mg/l. However, at 30+ mg/l it can impart a sharp sour/bitter flavor Provided by Ken Woodson & the North Texas Home Brewers Association

Ions in Brewing Important Cations Sodium (Na+) Poisonous to yeast and harsh tasting when levels are too high. Unpleasant harshness when combined with Sulfate Contributes sour salty taste at reasonable levels. For brewing, should be below 50 mg/l Provided by Ken Woodson & the North Texas Home Brewers Association

Ions in Brewing Important Anions Bicarbonate (HCO3)- Neutralizes acids in dark malts Acts as a pH buffer Under 50 mg/l unless it is balanced by Calcium or dark malts. Provided by Ken Woodson & the North Texas Home Brewers Association

Ions in Brewing Important Anions Sulfate (SO4)-2 Accentuates hop bitterness and dryness at high concentrations. It is strongly bitter above 500 mg/l For non highly hopped beers, levels should be below 150 mg/l Creates an unpleasant harshness if combined with Sodium Provided by Ken Woodson & the North Texas Home Brewers Association

Ions in Brewing Important Anions Chloride (Cl)- Enhances sweetness at low concentrations, but at high levels it impairs yeast flocculation. Increases beer stability and improves clarity For light beers 1-100 mg/l is common; however, it can be as high as 350 mg/l for beers with gravity larger than 1.050 Provided by Ken Woodson & the North Texas Home Brewers Association

Water Analysis - pH pH, or potential hydrogen, is important in brewing Enzymes that break down starches work best over a pH range of 5.2 – 5.5 If pH of sparging water is greater than 6.0, then tannins can leak into wort causing harsh flavors. Rapid drop in pH during fermentation is common, which inhibits bacterial activity Provided by Ken Woodson & the North Texas Home Brewers Association

Water Analysis - Alkalinity Alkalinity is the amount of alkaline ions present and is usually expressed as an equivalent amount of CaCO3 For water pH between 7 and 9, alkalinity is basically the bicarbonate ion, expressed as an equivalent amount of CaCO3 Alkalinity, as equivalent CaCO3, should be less than 50 mg/l for brewing pale beers Provided by Ken Woodson & the North Texas Home Brewers Association

Water Analysis - Hardness Informally, water hardness was determined by the amount of suds produced in soap, the harder the water, the fewer the suds. Water hardness is measured as the amount of Calcium (Ca+2 ) and Magnesium (Mg+2) dissolved in water and is usually expressed as an equivalent amount of CaCO3 Hardness = (100/40)* (mg/l of Calcium) + (100/24)* (mg/l of Magnesium) Provided by Ken Woodson & the North Texas Home Brewers Association

Water Analysis - Hardness Temporary Hardness Calcium reacts with bicarbonate (HCO3)- , when heated, to precipitate Calcium carbonate (CaCO3), which reduces the amount of Calcium. The Calcium that can be removed from the water through this boiling process is called temporary hardness Provided by Ken Woodson & the North Texas Home Brewers Association

Water Analysis - Hardness Permanent Hardness Permanent hardness is the water hardness that remains after boiling When alkalinity exceeds hardness, then the water hardness is mostly temporary. Conversely, if the hardness exceeds the alkalinity, the difference indicates permanent sulfate hardness. Provided by Ken Woodson & the North Texas Home Brewers Association

Water Adjustment for Extract Brewing Pre-treatment Odors/tastes: Chlorine, Iron, Sulfur, metallic, etc. Carbon Filters, Campden Tablets, Water Softeners, Green Sand Flavor Tweaking Sulfate for hop bitterness Sodium/Chloride for Malt accentuation Fermentation Issues (Rare) Zn, Ca, Mn, Mg = Yeast Nutrition, Beer Haze 30 Years ago, malt extract was for baking Now, mineral levels for mash chemistry fermentability have been done for you. Provided by Ken Woodson & the North Texas Home Brewers Association

Brewing Water Treatment Carbon Filtration Most municipal water supplies are treated with chlorine to inhibit bacterial growth. Chlorine can interact with wort to produce chlorophenols which can impart a plastic taste to beer Chlorine should be removed from brewing water. To remove chlorine you can use a carbon filter Provided by Ken Woodson & the North Texas Home Brewers Association

Brewing Water Treatment Reverse Osmosis and Distillation RO removes about 94% of the ions from water. If you use RO, then may need to add mineral salts to increase the calcium level to an appropriate level. Distillation removes all ions from water. Complete distillation is not recommended because it removes all yeast nutrients, however, partial distillation may be appropriate Provided by Ken Woodson & the North Texas Home Brewers Association

Brewing Water Treatment Boiling Recall that calcium reacts with bicarbonate (HCO3)- , when heated to a boil, to precipitate calcium carbonate (CaCO3), which reduces the amount of Calcium and the amount of bicarbonate. The reduction in bicarbonate will lower the pH of the water The process removes about 3 mg/l of calcium for every 5 mg/l of bicarbonate removed Provided by Ken Woodson & the North Texas Home Brewers Association

Mineral Salts Mineral salts are adding to brewing water to: Change the mash or sparge pH For pale malt mashes adding calcium sulfate will lower mash pH. For dark malt mashes adding calcium carbonate will increase mash pH Replicate the water profile of a famous brewing region To achieve specific flavors in beer Provided by Ken Woodson & the North Texas Home Brewers Association

Mineral Salts Common mineral salts added to brewing water Calcium Sulfate (Gypsum) CaSO4∙2H2O Ca 23.28%, SO4 55.79%, H2O 20.93% Increases water hardness and sulfate levels Magnesium Sulfate (Epsom Salts) MgSO4∙7H2O Mg 14%, SO4 55%, H2O 31% Calcium Carbonate (Chalk) CaCO3 Ca 40.04%, CO3 59.96% Increases Calcium and strongly buffers mash pH Provided by Ken Woodson & the North Texas Home Brewers Association

Mineral Salts Common mineral salts added to brewing water Calcium Chloride CaCl2∙2H2O Ca 27.26%, Cl2 48.23%, H2O 24.51% Adds Calcium and saltiness Sodium Chloride (Table Salt) NaCl Na 39.34%, Cl 60.66% Enhances bitterness and fullness of beer Provided by Ken Woodson & the North Texas Home Brewers Association

Mineral Salts Brewing Water Additions One gram of a mineral salt in one gallon of water at 68o F will increase the total dissolved solids by 264.2 mg/l. The 264.2 is the conversion from grams per gallon to milligrams per liter. Provided by Ken Woodson & the North Texas Home Brewers Association

Mineral Salts Brewing Water Additions For example, If you add 1.5 grams of gypsum to 10 gallons of your brewing water, how much of the Calcium ion have you added to the water? Answer: Mineral Salt ppm (1.5g/10gallon)*(1gallon/3.785liters)(1000mg/1g)=39.63mg/l Calcium ppm (39.63mg/l*.2328 )= 9.22 mg/l of Calcium Provided by Ken Woodson & the North Texas Home Brewers Association

Acidification The pH of brewing water can be reduced by adding a small amount of food grade acid. Typically, lactic, phosphoric, or sulfuric acid are used. As a general guide, you can add small amounts of food grade acid until the brewing water pH is around 7. For modified pale malts that will not undergo acid or protein rests, then you should add food grade acid until the brewing water pH is 6.0 Provided by Ken Woodson & the North Texas Home Brewers Association

Acidification Acids can be used more precisely to lower alkalinity, which will lower mash pH The amount of acid in milligrams/milliliter for common acids used in brewing: Lactic acid 85-90% w/w: 1,020 mg/ml Phosphoric acid 85-88% w/w: 1,445 gm/ml Sulfuric acid 95-98% w/w: 1,766 mg/ml Provided by Ken Woodson & the North Texas Home Brewers Association

Acidification To calculate the milliliters of acid required to lower alkalinity use the formula: (Alkalinity Reduction in CaCO3 )*3.7854*gallons of water milligrams of acid per milliliters Provided by Ken Woodson & the North Texas Home Brewers Association

Acidification Example If your brewing water has a pH of 7.9 and an alkalinity of 89, how many ml of 85% lactic acid should you add to 8 gallons of brewing water to reduce the alkalinity to 50 mg/l? Answer lactic acid ml = (89-50)*3.7854*8 = 1.2 ml 1,020 Note that a teaspoon is 5 ml Provided by Ken Woodson & the North Texas Home Brewers Association

Famous Brewing Waters The water at Burton upon Trent is very hard and the sulfate levels are extremely high. The high sulfate levels accentuate the bitterness in English Bitters and Pale ales The water in London, Dublin and Munich is high in bicarbonate which balances the dark malts used to brew porters, stouts, and bocks, in the respective regions Provided by Ken Woodson & the North Texas Home Brewers Association

Famous Brewing Waters Plzen water is very soft with low concentrations of dissolved ions. Decoction mashing is common in Plzen, in part due to soft water. The decoction process allows enzymes to work even though the calcium levels are very low. Provided by Ken Woodson & the North Texas Home Brewers Association

Famous Brewing Waters* Mineral Calcium Magnesium Sodium Sulfate Bicarbonate Chloride Plzen 7 2 5 15 Dortmund 225 40 60 120 180 Munich 75 18 10 150 Vienna 200 8 125 12 Burton 275 25 450 260 35 Dublin 55 20 Edinburgh 140 65 London 90 Plano 67 91 178 109 1 *Data from Greg Noonan's water workshop at the 1991 AHA Conference and are in ppm (mg/l) Provided by Ken Woodson & the North Texas Home Brewers Association