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0 Brewing Water 6 October 2008 A.J. deLange Burp Education Series Based on class given 28 April 1996.

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Presentation on theme: "0 Brewing Water 6 October 2008 A.J. deLange Burp Education Series Based on class given 28 April 1996."— Presentation transcript:

1 0 Brewing Water 6 October 2008 A.J. deLange Burp Education Series Based on class given 28 April 1996

2 1 Perspective The community (and I) have learned a few things about brewing water since 1996 (when I last gave this class) Then: Slavish attention to reproducing brewing cities ion profiles –A lot of people did a lot of hard work based on bogus data (published ion profiles) Now: Emphasis on getting proper mash pH with brewing liquor that more or less matches traditional profile –Recognition of Residual Alkalinity as a powerful tool for evaluating and comparing brewing water samples –Tweaking stylistic ions to taste (and authenticity). –Why put it in if you are just going to take it out (e.g. Munich Helles)? –Often no information whatsoever on type of water required for a particular style - this is starting to change Most modern water supplies are generally good for brewing most beers. –Big Exception: Chloramine!! Note: Red font denotes key concepts - take special note of these

3 2 Approach Water chemistry is intricate and detailed if not complex In a couple of hours I can only skim the surface –There wont be time to thoroughly explain many of the concepts –Go back and look at the slides again at leisure –Some slides are in here with that intention - we wont do much more than mention them For practical knowledge you must explore further on your own –Papers on CD Most of the bloody details are found in the Cerevesia paper –Spreadsheet on CD This will be your best friend in terms of practical applications. –Books (see list at end) –Internet

4 3 There are Two Aspects to Brewing Water I: Water chemistry has great influence on mash pH thus great influence on nature of the beer –Full understanding of this requires knowledge of acid- base equilibrium chemistry, intricate calculations… Reviewed in Cerevesia article (on handout CD) –Fortunately, a simple (to use) Excel spreadsheet (on handout CD) can handle all of this for you You need to know how to use it and what the numbers mean - not how to program it II: Certain ions influence flavors - just as they do in any other form of cooking. –Salt to taste

5 4 Your Goals Understand –Relationship between beer and water its made from –Fundamentals of chemistry related to brewing water Atoms, molecules, ions, moles, equivalents, acids, titration… –pH, Alkalinity, Residual Alkalinity (RA) and Hardness These are the key concepts Be able to… –Read a water report Check it for validity (using spreadsheet) –Treat water to Remove chlorine and chloramine Reduce bicarbonate (alkalinity) and iron (if you have it) Control the pH of your mash Establish an approximation to a desired ion profile

6 5 Quotations Wine is made by farmers. Beer is made by engineers. (?) A distinction is frequently drawn in the industry between the theoretical man who tries to explain everything from a scientific point of view, and the practical man who relies on empirical knowledge and experience. A good brewer should be able to steer a middle course between these two extremes - Jean deClerck The third group, the smallest, are the Noonanians, the triple decoction cultists. Eighteen hour brew days, elaborate water modifications: you wonder how they stay married. - Delano DuGarm

7 6 Quotations II Water contains three ions which influence the pH of wort: bicarbonate, calcium and magnesium. The bicarbonate ion has a pH raising effect, the other two lower it. The pH lowering effect of magnesium ions is only half that of calcium ions. Depending on the ratio of the waters content of bicarbonate on the one hand and calcium and magnesium on the other, the pH raising effects of the bicarbonate is more or less compensated or balanced. Thus experiment has shown that to balance 1 equivalent of bicarbonate ion 3.5 equivalents of calcium or 7 equivalents of magnesium ion are required. With respect to the pH raising property of the total alkalinity of the brew water, thus, a definite part is balanced. The remainder, the residual alkalinity, can serve as a measure of the pH raising effect of the water. –Paul Kohlbach, Die Einfluss des Brauwassers auf das pH von Würze und Bier, Monatsschrift für Brauerei, Berlin, Mai 1953 –Whole paper is on CD. Read it!

8 7 Topics Part 0: Beer and Water Part 1: Fundamentals of Chemistry Part 2: Carbon Dioxide, Water, Limestone, pH, Hardness, Alkalinity Part 3: Adding Malt Phosphate to the Picture, Residual Alkalinity Part 4: Water reports Part 5: Water testing Part 6: Water Treatment Part 7: Synthesis of water with a given ion profile Part 8: Comparison Beer

9 8 Handout CD Contains… A copy of this presentation Translation of Paul Kohlbachs seminal paper (1953) A set of slides from a lecture given at DeClerck Chair XI (Louvaine-la-Neuve, Sept 2004) Copy of the paper (based on that lecture) from Cerevesia 29(4) 2004 Microsoft Excel spreadsheet which implements the significant brewing water chemistry calculations Two part BT article on Alkalinity (unpublished) BT article on Chloramine New York Times Science article (geology and beer). 54 recipes for water of various brewing cities from common salts and distilled water.

10 9 Part 0 Overview - Beer and Water

11 10 Water and Beer Style Water is heavy (1 kg/L ~ 8.3 Lbs/gal.) Barley, malt and hops can be cost effectively moved fairly long distances - water can not. Therefore, absent ability to treat it, local water determined what local beer was like –Soft water: Bohemian Pils –Hard, bicarbonate Water: Munich Dunkles, London Ales Remove bicarbonate and you can make Helles –Hard Sulfate Water: Burton Ales

12 11 The First of the Two Aspects Bicarbonate is a base - its alkaline –It raises mash pH ~ malt enzymes become less effective –It must be neutralized or removed (so pH is kept low) Hardness (Ca ++, Mg ++ ) plus malt phosphate neutralize it –Alkalinity (water bicarbonate) not neutralized by water hardness + malt phosphate is called Residual Alkalinty Acid neutralizes it –Sulfuric, hydrochloric, lactic, acid in dark malt –High alkalinity water requires lots of hardness, acid and or dark malt to neutralize it (and conversely) Theme: Contest between alkalinity (bad) and hardness (good) for control of mash pH.

13 12 Hardness & Alkalinity for Several Cities RA = Alkalinity - (Ca_hardness + Mg_hardness/2)/3.5 Good Bad OK

14 13 Part 1 Fundamentals of Chemistry: Atoms, Molecules, Ions, Acids, Bases

15 14 For Further Information… We can only skim (rapidly) the surface at the highest level today Nothing here beyond college freshman chemistry –Should today stimulate your interest, review freshman chemistry or biochemistry text Pay particular attention to ionic equilibrium (law of mass action), acid/base chemistry, Henderson Hasselbalch equation. –Read Cerevesia article on CD

16 15 Atoms Smallest particle of elemental matter with nucleus of positively charged protons and uncharged neutrons… –… of mass ~1.673E-24 grams (protons and neutrons slightly different) Surrounded by negatively charged electrons –With mass E-24 grams (1/1822 of proton) –Number of electrons equals number of protons –Atom has a net charge of 0. –Electrons group into shells –Most of the elements well deal with like to have 8 electrons in outer shell The number of protons (and electrons) determine which element the atom is –1: H, 2: He, 3: Li, 4: Be, 5: B, 6: C 7: N, 8: O 9: F, 10: Ne Number of neutrons determines which isotope –6 protons + 6 neutrons ~ 12 C (normal); 6p + 8n ~ 14 C (radioactive)

17 16 Chemical Symbols Each element (atom type) is represented by a symbol –Its often pretty obvious which element is meant… H ~ Hydrogen C ~ Carbon O ~ Oxygen Ca ~ Calcium Mg ~ Magnesium S ~ Sulfur –But not always… Na ~ Sodium (L. Natrium) K ~ Potassium (L. Kalium) Fe ~ Iron (L. Ferrum) Hg ~ Mercury (L. Hydrargyrum) Combined atom symbols represent compounds: –NaCl ~ Sodium chloride HCl ~ Hydrochloric Acid CaCl 2 ~ Calcium chloride H 2 CO 3 ~ Carbonic acid CaCO 3 ~ Calcium Carbonate CaSO 4.2H 2 O Calcium Sulfate with 2 waters of hydration. –Subscript indicates number of atoms in molecule 1 Molecule of CaCO 3 has 1 calcium, 1 Carbon, 3 Oxygen atoms Ion (electrically charged atom or molecule) is indicated by element or compound symbols with charge shown –Na + ~ Sodium ion Ca ++ ~ Calcium ion HCO 3 - ~ Bicarbonate

18 17 IONS Noble gasses Helium, Neon, Argon… have complete electron shells ~ chemically stable Atoms may take on or release electrons to complete or leave a complete shell –Sodium ([Ne]+1e - ): Na --> e - + Na + Sodium Ion –[Noble gas] represents the electronic structure of that gas Giving up 1 electron leaves Neon (10 e - ) shell structure Could give it to e.g. chlorine… –Chlorine ([Ne]+7e - ): Cl + e - --> Cl - Ion ([Ne]+8e - = [Ar]) –Calcium ([Ar]+2e - ): Ca --> 2e - + Ca ++ Ion Take away 2 electrons leaves Argon shell structure –Hydrogen (1 e - ): H --> e - + H + Hydrogen Ion Naked proton (quickly attaches to a water molecule)

19 18 Molecules Atoms can also share (or give) electrons with (to) other atoms in order to complete shells –Carbon (C) has 4 electrons in its outer shell: [He]+4e - –Hydrogen (H) has 1 electron: 1e - –If carbon shares the electrons from each of 4 hydrogen atoms it completes its outer (valence) shell : [He] + 4e - + 4e - (shared from hydrogens) ~ [Ne] –Each hydrogen shares one of carbons electrons 1e - + 1e - (shared from carbon) ~ [He] –CH 4 is the gas methane Na gives e - to Cl. Na + attracts Cl - --> NaCl Atoms so combined are called molecules the constituents of compounds.

20 19 Dissociation Some molecules (acids) may release or take on (bases) protons (hydrogen ions) thus becoming ions themselves –Carbonic Acid: H 2 CO 3 --> H + + HCO 3 - Bicarbonate ion –Ammonia (base): NH 3 + H + --> NH 4 + Ammonium ion –Sulfuric Acid: H 2 SO 4 --> H + + HSO 4 - Bisulfate ion –Hydrochloric Acid: HCl --> H + + Cl - Chloride ion Ions can do this too and become doubly ionized or un-ionized –Bicarbonate ion: HCO > H + + CO 3 -- Carbonate ion –Bicarbonate ion: HCO H + --> + H 2 CO 3 Carbonic acid Molecules (or ions) which give up protons are acids in the Lowry- Brønstead sense (there are other definitions) Molecules (or ions) which take up protons are bases in the Lowry- Brønstead sense.

21 20 Chemical Equations Reactants on left, products on right Equation in the sense that numbers of atoms (of each type) and charges must be equal on each side Ca(OH) 2 + Ca HCO > 2CaCO 3 + 2H 2 O –This says that 1 molecule of calcium hydroxide (slaked lime) reacts with 1 calcium ion and 2 bicarbonate ions producing 2 molecules of calcium carbonate (chalk) which precipitates (underbar) and 2 molecules of water –2 Calcium, 2 Carbon, 8 Oxygen, 4 Hydrogen, 0 charge on each side –--> indicates that reaction proceeds from left to right but not in other direction (many, indeed all, reactions proceed in both directions if conditions are right but one is sometimes preferred.) This reaction is commonly used by brewers to remove bicarbonate from alkaline water. Because it removes calcium, a component of hardness, as well it is usually thought of as a water softening treatment.

22 21 Measurement of Chemicals RE last slide: each molecule of lime will remove 2 bicarbonate ions. How much lime do we need to buy to process x gallons of water? Clearly we need to have some idea of what a molecule weighs and how many we need. Molecules, like atoms and ions, are made up of protons and neutrons which contribute nearly all the weight as electron weight is negligible One proton weighs 1 Dalton (1 Atomic Mass Unit) How many protons weigh one gram? –Answer: 6.023E+23 called Avogadros Number. –Avogadros number of Daltons = 1 gram –Avogadros number of anything (atoms, molecules, ions, electrons, rutabagas, even furry blind subterranean mammals) is called one mole

23 22 Gram Molecular Weights ~ Weight of 1 mole Hydrogen: 1 proton. 1 mole should weigh about 1 gram. Actual GMW Oxygen: 8 protons, 8 neutrons. 1 mole should weigh about 16 grams. Actual value Calcium: 20 protons, 20 neutrons. 1 mole should weigh about 40 grams. Actual value Ca(OH) 2 : 38 protons, 38 neutrons. 1 mole should weigh about 74 grams. Actual GMW HCO 3 - : 31 protons, 30 neutrons. 1 mole should weigh about 61 grams. Actual GMW Thus 1 molecule of Ca(OH) 2 reacting with 2 HCO 3 - ions implies that 6.023E23 (1 mole = grams) of Ca(OH) 2 will react with E23 (2 moles = grams) of HCO 3 - and so on in that proportion Example: To decarbonate water with 61 milligrams (mg) of bicarbonate (1 millimole) per liter would require 1/2 mMol of Ca(OH) 2 weighing /2 = mg per liter.

24 23 Equivalent Weight Sometimes specified weights are based on moles of charge rather than moles of ions or atoms Singly charged HCO 3 - : 31 protons, 30 neutrons. GMW means grams has a charge of 1 mole of (-) charges. Equivalent weight = Doubly charged Ca ++ : 20 protons, 20 neutrons. GMW means grams carries 2 moles of (+) charge grams carries 1 mole. Equivalent weight = Equivalent weight = gram molecular weight divided by charge. Alkalinity (HCO 3 - ) and hardness (Ca ++, Mg++) are often expressed in milliequivalents per liter (mEq/L sometimes called mVal/L or just mVal). Sometimes given as 50 times mEq/L - called parts per million as CaCO 3 –This is seen a lot. Note: 1 ppm ~ 1 mg/L (as water weighs ~ 1 kg/L) CaCO 3 + CO 2 + H > 2HCO Ca mg 1mMol 44mg 1mMol 18mg 1mMol 122mg 2mMol 2mEq 100ppm as CaCO 3 40mg 1mMol 2mEq 100ppm as CaCO 3

25 24 Example of Calculation Being an environmentally conscientious brewer you wish to neutralize your standard lye cleaning solution (1 pound lye in 5 gal water) before dumping it down the drain. How much acid is needed? –Na(OH) + H 2 O --> Na + +(OH) - + H 2 O Lye GMW 40: 1 lb = 454 g ~ 454/40 = Mol ~ Eq (OH) - H + + (OH) - --> H 2 O Need Eq H + Sulfuric Acid MW 98: H 2 SO 4 --> 2H + + SO 4 -- –11.36/2 Mol H 2 SO 4 yields Eq H + –98*11.36/2 = 556 grams ~ 1.23 lbs concentrated sulfuric acid required. –11.36 Mol of Na + & 11.36/2 Mol SO 4 -- (11.36/2 Mol Na 2 SO 4, MW 142 ~ 11.36*142/2 = kg) go down drain (wrong on CD) Hydrochloric Acid MW 36.46: HCl --> H + + Cl - –38% HCl solution (23 Baume) is Normal meaning it contains Eq H + per litre. Therefore need 11.36/12.29 = L of 38% HCl –664 g NaCl (table salt) goes down drain Add acid to solution until pH neutral rather than relying on calculation

26 25 Another Example Calculation Water tests 3 mg/L available chlorine (from chloramine). How much potassium metabisulfite (K 2 S 2 O 5 MW ) is required to treat 20 gal (76 L) –2K + + S 2 O H 2 NCl + 3H 2 O --> 2K + + 2SO H + + 2Cl - + 2NH 4 + –Each mole of chlorine requires 0.5 mole of bisulfite ion and produces 1 mole of sulfate, 1 equivalent of hydrogen ions, 1 mole of chloride ions and 1 mole of ammonium ions. –3 mg/L Cl ~ 3/35.45 = mMol/L requiring mMol/L metabisulfite and producing mMol/L sulfate, hydrogen, chloride and ammonium ions. –The GMW of potassium metabisulfite is mg/mMol so we need 9.4 mg/L or 714 mg total (one lot of Campden tablest we measured weighed 695 mg) –The hydrogen ions, mEq/L represent a reduction in alkalinity of 50 times this or 4.2 ppm as CaCO 3. –As each bound chlorine atom is converted to a chloride ion the chloride level will increase by 3 mg/L – mMol/L * 96 mg/mMol ~ 8.12 mg/L increase in sulfate (Pils brewers take note) – mMol/L*18 mg/mMol ~ 1.5 mg/L increase in ammonium ion (your yeast will love it)

27 26 Part 2 Carbon Dioxide, Water & Limestone; Hardness & Alkalinity

28 27 Carbon Dioxide: CO 2 MW Spewed by volcanoes Taken up by plants -> sugar, starch… oxygen –6CO 2 + 6H 2 O > C 6 H 12 O 6 + 6O 2 Released by carbohydrate oxidation (including respiration, fermentation, decay…) –C n H 2n O n + nO 2 --> nCO 2 + nH 2 O A greenhouse gas –Though not a very effective one (10% re water vapor) Present in the atmosphere to the extent of 0.03% (0.0003Atm ~ 0.3 hPa) Absorbed/released by oceans, rivers, lakes –Sequestered by animals which build shells from it Dissolves in water to form carbonic acid which, in turn, dissolves limestone –This is the property of significance to brewers (and spelunkers). light

29 28 Water Continuous cycle of evaporation, condensation, precipitation… Ultimately comes to us from rain, snow, meltoff.. –Runs over surface of earth into a stream/pond… In equilibrium with atmospheric CO 2 Leaches substances from surface organic/inorganic materials with which it comes in contact –Or percolates into ground and is withdrawn from well penetrating aquifer In equilibrium with subterranean CO 2 (respiring bacteria) Typically more acidic (dissolved CO 2 ) Dissolves minerals from rock with which it comes in contact –Limestone caves Typically more mineral content than surface water Usually clearer, fewer bacteria than surface (well filtered) May be in the ground for years.

30 29 Carbonic Acid MW CO 2 dissolves in water to form carbonic acid… –CO 2 + H 2 O H 2 CO 3 * –* indicates this is both dissolved but not hydrated CO 2 and hydrated CO 2 –Arrow is two headed. Carbonic acid can decompose into water and CO 2 … which can give up a proton to form bicarbonate ion… –H 2 CO 3 * H + + HCO 3 - –Ability to give up proton defines H 2 CO 3 as an acid –In reverse, HCO 3 - can take up a proton to form H 2 CO 3. This defines a base …which can give up its proton to form carbonate… –HCO 3 - H + + CO 3 -- –The fact that it does so defines bicarbonate as an acid. –Thus bicarbonate is an acid and a base (it is amphoteric) Which it behaves as depends on pH (at brewing pH it is basic) –In reverse, CO 3 -- takes up a proton to form HCO 3 -. CO 3 -- is a base …which can coalesce with calcium ion to precipitate chalk –CO Ca ++ CaCO 3 (only slightly soluble)

31 30 Calcium Carbonate MW Ca ++ + CO > CaCO 3 (lime, chalk, limestone) –Happens in the bodies of marine animals –Main source of limestone - sequesters CO 2, sends to bottom –10% of all sedimentary rock Happens when hard bicarbonate water is heated –Popular method for decarbonating brewing water Or when hard bicarbonate water evaporates –Shower heads –Stalactites/Stalagmites Dissolved by carbonic acid - source of calcium hardness –CaCO 3 + H 2 O + CO 2 --> CaCO 3 + H 2 CO 3 --> 2HCO Ca ++ –Surface and ground water are hard & alkaline –Cave formation: underground p a CO 2 much higher (hence more carbonic) because of respiring bacteria

32 31 Law of Mass Action In any reaction mA + nB kC + jD {C} k {D} j /{A} m {B} n = K, a constant (constant temp.) –{A} = activity of A –For a gas {A} is approximately the partial pressure –For a dissolved substance {A} is approximately the concentration (moles per liter) –For a solid {A} = 1 Define p{A} = - log 10 {A} Then kp{C} + jp{D} - mp{A} - np{B} = pK If A + B C (underscore ~ precipitation) then –{A}{B} < K s (solubility product) No precipitation occurs –{A}{B} > K s supersaturated. Precipitation usually occurs –{A}{B} = K s saturated. No precipitation –p{A} + p{B} = pK s at saturation

33 32 Carbonic - Loss of 1st Proton H 2 CO 3 * H + + HCO 3 - {H + }{HCO 3 - }/{H 2 CO 3 * } = K 1 pH + p{HCO 3 - } - p{H 2 CO 3 * } = pK 1 –Henderson-Hasselbalch Equation –p{x} = - log x –p{H + } = pH is special - more to follow on this pH - pK 1 = p{H 2 CO 3 * }- p{HCO 3 - } –rearranged 10 pH - pK 1 =10 p{H 2 CO 3 * } - p{HCO 3 - } = {HCO 3 - } / {H 2 CO 3 * } = r 1 = ratio bicarbonate to carbonic –Took antilog of both sides –Note if pH = pK 1 then r 1 = 1; {HCO 3 - } = {H 2 CO 3 * }

34 33 Carbonic - Loss of 2nd Proton HCO 3 - H + + CO 3 -- {H + }{CO 3 -- }/{HCO 3 - } = K 2 pH + p{CO 3 -- } - p{HCO 3 - } = pK 2 pH - pK 2 = p{HCO 3 - }- p{CO 3 -- } 10 pH - pK 2 =10 p{HCO 3 - } - p{CO 3 -- } = {CO 3 -- } / {HCO 3 - } = r 2 = ratio carbonate to bicarbonate If pH = pK 2 then r 2 = 1; {CO 3 -- } = {HCO 3 - } Solutions tend to resist pH changes near their pKs –This is called buffering

35 34 H 2 CO 3, HCO 3 -, CO 3 -- Fractions If there are x moles of carbonic, there are r 1 x moles of bicarbonate and xr 1 r 2 moles of carbonate for a total of C T = x(1 + r 1 + r 1 r 2 ) =xd C T = total carbo The fraction which is carbonic is x/xd = 1/d = f 1 The fraction which is bicarbonate is r 1 times this = r 1 /d = f 2 The fraction which is carbonate is r 2 times this or r 1 r 2 d = f 3

36 35 Distribution of carbo species pH s Alkalinity is defined as the number of mEq of acid required to change the pH of a sample from its pH at the source (pH s ) to pH 4.3 pK pK

37 36 Alkalinity Definition: the number of mEq of acid required to change pH of a sample to a reference pH (usually pH r = 4.3) –Sum of Acid required to change carbonate to carbonic Acid required to change bicarbonate to carbonic Acid required to increase {H + } to (1000)10 -pH r mEq/L Acid require to neutralize (OH) - r ~ reference pH, s ~ sample pH, pK w = 14 Units: mEq/L (thats why the factor of 1000 is there) C T = total mmol/K carbonic, bicarbonate, carbonate Equation can be solved for C T if alk, pHr and pHs are known Thus choice of pHr is somewhat arbitrary alk = C T (f 1,r - f 1,s + f 3,s - f 3,r ) + (1000)10 (pH s -pH r ) + (1000)10 (pK w -pH r -pH s )

38 37 Solubility Product {Ca ++ }{CO 3 -- }< K s Solubility Product –If {Ca ++ }{CO 3 -- } = K s water is called saturated p{Ca ++ }+p{CO 3 -- }< pK s Calcium carbonate is not very soluble in water To precipitate carbo (and hardness) establish conditions which violate inequality –Increase pH & thus f 3 (Drive off CO 2 by heat, sparge) –Decrease K s (raise temperature) –Increase {Ca ++ } (add gypsum or CaCl 2 ) –Combinations (Ca(OH) 2 increases pH and {Ca ++ })

39 38 Combine Equations Add Eqns for dissolving CO 2, CaCO 3 saturation, water dissociation and electric neutrality CO 2 Dissolves: A proton is lost: A 2nd proton is lost: CaCO 3 Saturation: Water dissociates: The total charge is 0: Define: Substitute into charge neutrality equation, Solve (root finder) for pH which satisfies this equation Substitute back pf m accounts for fact that solutions are not ideally dilute. We will ignore this.

40 39 Why All this Horrible Math? It is what allows us to … –Validate a water analysis –Calculate alkalinity and estimate the acid required for proper mash pH –Synthesize any water ion profile from any starting water (e.g. salt additions to get Burton water from my well water) –Determine whether water is stable (saturated with respect to CO 2 or CaCO 3 –Make charts like one on next slide It is what is behind the spreadsheet on the CD

41 40 CO 2 Over Water in Equilibrium with CaCO 3

42 41 Review - Dissolving Limestone Alkalinity comes from limestone and the carbonic acid which Is required to dissolve it. Calcium hardness comes from dissolved limestone.

43 42 pH Søren Peter Lauritz Sørenson ( ) –Worked at Carlsberg Laboratory –Studied amino acids, proteins enzymes –Their behaviour (total electric charge) depends on hydrogen ion concentration (mechanism weve been discussing). –Sought convenient scale for specifying {H + } (1909) –Called it pondus (L. a weight) hydrogenii i.e. pH = -log 10 {H + } –For pure water {H + } = Mol/L thus pH = 7 –For.001 N acid {H + } = Mol/L thus pH = 3 pH < 7: Acid, sour, beer, wine, soda (phosphates), vinegar, lemon, lime (citrus), sauerkraut, sour cream, kimche pH ~ 7: Neutral, water, blood, brine pH > 7: Base, bitter, lye, lime (slaked), soda ash

44 43 Importance of pH in Brewing Necessary to calculate carbo species distribution in water As pH changes charge distribution on proteins it changes conformation of enzymes –Brewing water treatment is done to get enzymes properly conformed for protein lysis, starch to sugar conversion… –Happens in range pH Proper charge distribution on proteins (chains of amino acids) in boil (iso-electric point~ net charge 0) enhances coagulation H 3 N + CRHCOOHH 3 N + CRHCOO - H 2 NCRHCOO - H+H+ H+H+ pH 1 Q = 1pH 6 Q = 0pH 14 Q = -1 Charge (Q) shown for simplest amino acid, Glycine (R = H) Note: For some amino acids (Arginine, Lysine, Tyrosine….) R may be ionizeable in which case other charge values are possible

45 44 Importance of pH II Tanins not extracted from barley husks if sparge pH < 6 Yeast produce acid to kill competing organisms –Thus pH drop is first sign of healthy fermentation pH has an effect on stability of colloids in finished beer. pH modulates formation of melanoidins IOW, each part of the brewing process proceeds best in a range of pH (and temperature) –XI DeClerck Chair: 3 Days of lectures on pH Paradox devoted to this subject Advanced brewer feels as helpless without his pH meter as he does without his thermometer.

46 45 pH Measurement Originally with dye which changes color at particular pH –Litmus Test from a lichen (red 7) –Phenolpthalein, bromcresol red, methyl orange (4.3) … Electronically: potential developed across specially prepared (delicate) glass bulb dependent on pH difference between inside and out –Potential measured between electrode inside bulb and reference junction electrically connected to solution being measured (outside bulb) –Very feeble current. Extremely high impedance amplifier required –57 millivolt change per unit pH change Depends on temperature - temperature compensation essential Note: pH also changes with temperature (because pKs do). This is a separate effect Special field effect transistors (ISFET) –Much more durable, store dry Modern meters more dependable, last longer, less expensive, feature rich (ATC, auto buffer recognition) but still not for the casual user. Must be calibrated frequently with buffers of known pH

47 46 Part III Adding Phosphate, Residual Alkalinity

48 47 Phosphoric Acid Chemistry Same as carbonic except –The oxide is a solid: P 2 O 5 + 3H 2 O --> 2H 3 PO 4 Compare: CO 2 + H 2 O --> H 2 CO 3 General reaction for oxoacids –Includes carbonic, phosphoric, nitric, sulfuric –Three protons: H 3 PO 4 --> H + + H 2 PO > 2H + + HPO > 3H + + PO Three (not the same as carbonic) pKs (2.12, 7.21, 12.67), three rs, three fs. Calcium phosphate is very insoluble –The smallest amount of phosphate will pull out lots of calcium –This is why trisodium phosphate was used as water softener 3Ca Na 3 PO 4 ---> Ca 3 (PO 4 ) 2 + 6Na + –And why malt phosphate lowers pH of hard water Net reaction releases protons (hydrogen ions) - later slide

49 Phytic Acid from Malt 48

50 49 Malt Phosphate Up to 2% of malt weight is phosphate –In the form of phytin, salt of myoinositol hexaphosphate Enzyme phytase breaks down phytin releasing inorganic phosphate (H 2 PO 4 -, HPO 4 -- ) and B vitamin myoinositol (good for yeast) –Phytase survives only mild kilning i.e. active in pale base malts only Phosphate coalesces with any calcium in water, precipitates and releases protons which lower mash pH. Paul Kohlbach observed that 3.5 mEq of Ca ++ or 7 mEq Mg ++ neutralize 1 mEq alkalinity –Neutralize here means that the pH of a mash with all alkalinity neutralized has same pH as a distilled water mash (~ 5.7) –Defined Residual Alkalinity: RA = alk. -({Ca ++ } + {Mg ++ }/2)/3.5 Alkalinity, hardnesses and residual alkalinity all in units of either mEq/L or ppm as CaCO 3. –Also noted pH shift for each mEq/L (50 ppm) of RA

51 50 Residual Alkalinity Chart Residual Alkalinity: RA = alk. -({Ca ++ } + {Mg ++ }/2)/3.5 Define Hard_eff = -({Ca ++ } + {Mg ++ }/2) –Effective hardness equals calcium hardness plus half magnesium hardness Then RA = alk. - Hard_eff/3.5 Solve for alk: alk = RA + Hard_eff/3.5 Plotting alk vs. Hard_eff for a given RA gives a straight line which crosses the alk axis at RA and has slope 1/3.5 This is the chart from earlier in the presentation RA values in increments of 50 ppm as CaCO3 corresponding to pH shift increments of Above heavy line (RA = 0) pH will be higher than distilled water mash, below it, pH will be higher RA < 50 generally OK (dotted line)

52 51 RA Chart

53 52 Use of Chart - Example Edinburg (Edn2): Alk 180, Hard_eff 340, RA 85, pH ~ 5.89 is too high Reduce alkalinity by = 80 to get to RA ~ 0 and pH ~5.75 –Add 80/50 = 1.6 mEq/L acid (e.g. HCl, H 2 SO 4 ) –Decarbonate water. Can get to approximately 50 ppm as CaCO 3, RA ~ 35, pH 5.69 Could also get to this RA by adding ( )/50 = 2.6 mEq/L acid Add ( )/50 = 5.6 mEq/L hardness –5.6 mEq/L Ca ++ ~ 2.8 mMol/L CaSO 4.2H 2 0 ~ 482 mg/L gypsum

54 53 Carbo + Phosphate System 10Ca HCO H 2 PO H 2 O -> Ca 10 (PO 4 ) 6 (OH) CO 2 + 2H + +12H 2 O

55 Demonstration Prepare phosphate buffer from 40 mMol/L KH 2 PO 4 Add Na 2 HPO 4 to pH 5.92 –Phosphate buffers very commonly used to control pH in laboratory Simulates phosphate distribution in distilled water mash Add strong CaCl2 solution drop by drop and observe pH pH falls gradually at first, then as precipitate (hydroxyl apatite) forms, more rapidly This is the mechanism by which hard water produces acid to neutralize alkalinity –There is no alkalinity here (buffer made with distilled water) –Were alkalinity present, pH drop would no be so dramatic as some of the H + released would go to neutralize it. 54

56 55 Part IV Water Reports

57 56 Water Report Key Parameters 1st Aspect Alkalinity –Measure of acid required to lower sample pH to 4.3 ~ buffering capacity of water –Indicator of amount of acid (from any source) required to establish proper mash pH ( ) –Measure of bicarbonate content Hardness –Measure of amount of calcium and magnesium in sample. Mg ++ and Ca ++ should be measured and reported separately –Indicator of extent to which water is capable of offsetting its alkalinity (reaction with malt phosphate) pH –Permits calculation of ion balance (quality check on report) –Permits calculation of amount of bicarbonate from alkalinity –Otherwise, not really that important

58 57 Water Report Key Parameters 2nd Aspect Sulfate –Large effect on the way hops are perceived High value for assertive, dry hop flavor Low (15mg/L or less) for beers using a lot of noble hops Sodium –Leads to salty taste in high concentrations Chloride –Leads to salty taste in high concentration, pasty in very high >300mg/L –Lends round, sweet quality in modest amounts Iron –The less the better - tinny, inky, metalic taste For Brewing, < 0.1 mg/L ; EPA secondary limit < 0.3mg/L Copper –Metalic taste. May indicate pipe corosion Need a small amount. Yeast enzyme co factor Chlorine and, in particular, Chloramine –Chloramine forms ppb detectable chlorphenolics (plastic taste)

59 58 Calcium Most important brewing ion? From dissolved limestone, gypsum Important enzyme co-factor –Protects -amylase from heat –Stimulates proteolytic and amylitic enzymes –Reaction with phytin lowers mash pH Favors rapid, bright runoff Facilitates break formation Improves yeast flocculation Precipitates oxalate in beer (enhanced clarity)

60 59 Magnesium Part of hardness - half as effective as Calcium in RA reduction (mEq for mEq). Laxative above 120 ppm esp. with SO 4 -- Sour/bitter quality at > 30 ppm –Hence remove if above this level by split treatment (to be covered) –Not a problem with local (DC area) water There are claims that it lowers cardiac mortality

61 60 Sources of Water Reports Your supplier (municipality, water company…) –Go to its website, call or visit the office –You are likely to get a lot of promotional material about DBP rule, cryptosporidium, industrial contaminants etc. –Persist until you get an inorganic report including alkalinity and hardness Tell them that you are a brewer and this is what you need In earlier days some suppliers were reluctant to release information. Rare today –May not be timely e.g. summary for 2008 may not publish until 2009 Test results from commercial lab (individual or community well owners) –Make sure you get an inorganic analysis Organic and microbiological tests important too but not for your brewing needs –Ask other brewers (Ward Labs seems good) –Look in yellow pages/on web Results from tests you do yourself Profiles published in books, articles, papers, …

62 61

63 62 April: 50*32.5/20 (Ca) + 50*8.2/12.15 (Mg) = = total hardness. Compare to April total and calcium hardness numbers on previous slide. Could be different methods (e.g. AAS) samples taken on different days etc.

64 63

65 64 Imbal =100*( )/( )=12%

66 65 Water Report QA Check Any water report should be checked for internal consistency –Especially ones done by yourself or a lab –Lab often includes QA check as part of its report Check based on electrical neutrality i.e. sum of charges on anions should equal sum on cations. –As relative numbers of carbonic (0), bicarbonate(-1) and carbonate(-2) depend on pH calculation gets a bit nettlesome Must calculate C T, rs, fs –Spreadsheet on CD takes care of all this for you Full instructions for use on 2nd sheet.

67 66 Data entry in clear cells. Calculated results in colored cells Result in red cell should be < 10%

68 67 Available Water pH End Point pH Temp + for C, - for F20.0 Temp, C Temp K pK16.38 pK pKw14.16 A0.714 r r20.00 f1 = 1/d pHa pHa f f f1 + f2 + f31.00 No carb alkalinity Alk, + as CaCO3, - mEq/L66.50 Ca, + as CaCO3, - as mg/L56.00 Mg, + as CaCO3 - as mg/L48.00 Alk, mEq/K Gram Eq. WtCationsAnions Rough Carbo Rough Carbonic Rough Bicarbonate Rough Carbonate Total Carbo, mMol/L H2CO3, mg/L HCO3-,mg/L CO3--,mg/L H (OH) Sulfate. mg/L Chloride, mg/L Nitrate, mg/L Nitrite, mg/L Sodium, mg/L Potassium, mg/L Fe(II), mg/L Fe(III), mg/L Free Ammonia, mg/L Charges Imbal0.341 Imbal %7.32% Alkalinity66.50 Ca Hardness, as CaCO Mg Hardness, as CaCO Total Hardness, as CaCO Residual Alkalinity43.64ppm as CaCO3 Residual Alkalinity0.87mEq/L pH Shift RE Distilled Water0.07 Full set of measurements from 6341 Georgetown Pike well 30 Oct 2008

69 68 Worksheet for 30 Oct 08 Analysis

70 69 Part V Testing Water

71 70 Why Discuss Testing Test principals build on many of the things you have learned and most important test (alkalinity) mimics what happens in mash –Acid is added causing pH to drop –This is why alkalinity is a useful measure Explanation of how test is done will enhance your understanding of what the parameter means You may wish to do some testing yourself –Only way to get a feel for extent of temporal variation in your supply Most tests relatively easily carried out with kits –Get these from or aquarium supply companywww.hach.com –These things are getting expensive!

72 pH (Water Analysis Perspective) Need to measure/detect end point pH in alkalinity titration –This can be done with indicator dyes but woe betide the color blind (your instructor) –Electronic means more accurate, even for non Daltonians –Electronic meters now more reliable, inexpensive, durable, feature laden than before But be kind to your pH meter. Keep it clean and wet. Dont stick it into hot wort or mash! 71

73 pH Meter Voltage E = E0 + (RT/F)ln{H + } is developed across special glass membrane –E0 is voltage developed when {H+} = 1 –R (Bolzmans) and F (Faradays) are constants –T is temperature (Kelvins) E = E (RT/F)log{H + } = E0 - S*pH You (or the meter), must know E0 and S in order to determine pH = (E0 –E)/S This is where standard buffers come in –Placing the meter in 2 solutions of known pH and at known temperature allows meter to calculate S and E0 Thereafter meter can adjust readings for temperature response of electrode (ATC) But not, e.g. shift in wort pH from kettle to room temperature! 72

74 73 Alkalinity Defined as the number of mEq/L of acid required to lower pH of water sample from its initial value, pH i, to a reference pH, pH a pH a is part of definition of alkalinity and is usually 4.3 in brewing –May be based on equivalence: C T f 2,a (1000)10 -pH a –Analyst should report pH a. If he didnt use 4.3 –Important because you will solve for C T in report quality checking, synthesis Units of mEq/L (hence factor of 1000). Multiply by 50 for ppm as CaCO 3. C T = total millimoles/L carbonic, bicarbonate, carbonate in sample f s subscripted i refer to fractions at pH i f s subscripted a refer to fractions at pH a K w is dissociation constant of water (pK w = 20°C) Equals sum of acid required to –Convert initial fractions to fractions (mostly carbonic) at pH a –Increase hydrogen ion content to 10 -pH a –Decrease (by neutralizing to H 2 O) hydroxyl ion concentration to 10 pH a -pK w alk = C T (f 1,a - f 1,i + f 3,i - f 3,a ) (10 -pH a -10 -pH i +10 pH i -pK w -10 pH a -pK w )

75 74 Alkalinity II - Definition: The number of mEq of acid which must be added to a liter of water to bring pH to 4.3 (IOW, to convert most carbonate and bicarbonate to carbonic). Multiply by 50 for ppm as CaCO 3. Example sample pH i Where you go during titration Where youd Like to be in Mash tun - A rough indication of the amount of acid needed in the mash per L water - Measured by titration (addition of small amounts of acid until pH 4.3 is reached and reporting total used)

76 75 Alkalinity - Procedure Add an indicator (e.g. methyl orange or bromcresol green- methyl red) or a pH electrode to 100 mL sample Using a buret (conventional, digital, automatic, eyedropper, syringe…) add 0.1N (.1 mEq/L) acid (usually sulfuric) to sample until indicator turns color or pH 4.3 is reached –Other endpoint pH values can be used Report total number of mL acid used and endpoint pH –Multiply by 50 for ppm as CaCO 3. Kits available: Hach AL-AP $36.79 (100 tests) –Phenolphthalein (8.3) and Bromcresol Green-Methyl Red (4.3) indicators, sulfuric acid, measuring tube and bottle

77 76 Alkalinity Titration using pH Meter (Indicator also present) Sulfuric acid cartridge Digital Titrator: Plunger, lead screw, counter pH electrode pH Meter Dip Tube

78 77 Total Hardness (Ca ++ + Mg ++ ) Certain dyes (e.g. Eriochrome Black) are one color (red) in the presence of Ca ++ or Mg ++ and another color (blue) in their absence. Add such a dye to 100 mL of sample with buffer to set pH for sharp end point Titrate with a standardized strength chelating agent (EDTA) until the sample changes from red to blue. Report the number of mL chelant used (it has been calibrated to a convenient number of mEq or ppm or grains or dH (German degrees) etc. hardness per mL) This gives the total hardness (sum Ca + Mg) Kits available: Hach HA-71A $48.25 (100 tests) –Test tube/bottle, EDTA, Indicator, buffer, 20 ppm res.

79 78 Calcium Hardness Remove Mg ++ from water by raising pH (add suitable buffer) –Mg (OH) - --> Mg(OH) 2 (insoluble gel) Add dye and titrate with EDTA as before. This gives calcium hardness Subtract from total hardness to get magnesium hardness Kits available: Hach HA-4P Total and Calcium Hardness $65.05 (100 tests) 20 ppm as CaCO 3 resolution –Test tube and bottle, 2 indicators, 2 buffers, EDTA –Doubling amount of sample halves resolution (to 10 ppm) and halves number of tests per kit (to 50).

80 79 Hardness - Colorimetric Add dye to sample Divide into three portions Chelate Ca ++ and Mg ++ from first (excess EDTA) Chelate Ca ++ only from second (excess EGTA) Do nothing to third. Zero spectrophotometer with first - read second. Color depth difference is proportional to Mg ++ Zero specrophotometer with second - read third. Color difference is porportional to Ca ++ Add the two values for total hardness. No simple kits available - requires photometer or spectrophotometer.

81 80 Chloride Titration (kits available) –Diphenyl Carbazone forms a light pink complex with Hg ++ (mercuric) ions –Add DPC to sample, titrate with calibrated mercuric nitrate. –Precipitate of HgCl 2 forms. –When all Cl - has precipitated any additional Hg ++ forms colored complex with diphenyl carbazone. –Amount of Hg(NO 3 ) 2 used to obtain color is proportional to amount of chloride in sample Colorimetry (uses photometer) –Add Mercuric Thiocyanate Hg(SCN) 2 + Cl - ---> HgCl 2 + 2SCN - –Add ferric ion solution 3SCN - + Fe > Fe(SCN) 3 (red orange) –Measure depth of color formed with photometer. Note: Nasty mercury salts used in both these - Hg waste

82 81 Sulfate Barium sulfate is insoluble, Barium chloride is soluble. Add barium chloride to sample. Barium coalesces with sulfate to form insoluble BaSO 4 –Special agents in test reagent keep this in suspension Read turbidity in turbidimeter or spectrophotometer calibrated with standard solutions. No kits available - requires turbidimeter or photometer.

83 82 Sodium No practical chemical method Atomic Absorption/Atomic Emission Spectrophotometry –Sample is vaporized into flame. Optical absorption (or emission) at nm is measured. Ion Selective Electrode (ISE) –Similar to pH electrode except that its glass responds to log{Na + } rather than log{H + } –Expensive (hundreds of $) –Electrical response to calibrated standards is recorded (similar to pH). –Electrical response to sample is recorded Electrode is very slow to respond (especially at low concentrations) so automatic (e.g. strip chart) recording is preferred –Sample response is interpolated into calibration curve Some meters have the math built in

84 83 Sodium - Multiple Additions mV = U 1 + U n log{Na + } –U1 = response to 1 mg/L (unknown) –Un = response change per decade (only approximately known) –{Na + } = sample sodium concentration (what we want to know) Place electrode in known volume, v 0, of sample and record response Add spikes i.e. known volumes v 1, v 2 … mL of sodium standard solution of known strength S mg/mL. Then… mV 0 = U n log(v 0 {Na + } 0 ) + U 1 mV 1 = U n log(v 0 {Na + } 0 + S(v 1 )/(v 0 + v 1 )) + U 1 mV 2 = U n log(v 0 {Na + } 0 + S(v 1 + v 2 )/(v 0 + v 1 + v 2 )) + U 1 3 measurements are sufficient (though more are better) to allow estimation of {Na + } 0, U n, and U 1 Math is not basic (iterative non linear mmse estimation) but easily handled in a laptop –Excel Solver can do it!

85 84 Sodium ISE Recording Example

86 85 Analysis of Assymptotic mV Readings from Previous Slide Slope = , Intercept = mV, Concentration = ± mg/L; rmse = mV after 88 iterations. Un DOP = 4.74 mV/decade/mV; U0 DOP = 7.57 mV/mV; Concentration DOP = 4.48 mg/L/mV

87 86 Chlorine/Chloramine N,N-diethyl-p-phenylenediamine (DPD) added to sample Magenta Würster Dye formed if free chlorine is present Depth of color measured on photometer or judged relative to printed color patches, color wheels etc. Where chloramine is present it is converted to free chlorine first - total reading Difference RE free chlorine measurement is chloramine Kit: Hach CN-66 $45.29 (50 tests total; 50 free)- 0.1 ppm resolution –DPD, color wheel, 2 test tubes, test fixture.

88 87 Other Ions There are tests for dozens of other ions –Fe(II), Fe(III), Cu, Mn, Zn, NO 2, NO 3, K, Al, SiO 2, NH 3 … all based on similar principals –Kits are available for many (www.hach.com)www.hach.com Most of these are not important in brewing unless well in excess of typical values –i.e. in excess of EPA secondary limits Water tastes bad. –If in excess of primary limit, dont drink it or brew with it –Fe, Cu, Zn in excess may indicate corrosion Zn in particular may indicate leaching from brass in well fittings with potential that lead is being extracted as well –Brass containing lead now prohibited in wells

89 88 Summary of Measurement Techniques Titration –Addition of reagent of calibrated strength until an end point (color change, particular pH…) is reached Color development; color depth measurement –By visual comparison to printed chart, color wheel etc. –By use of photometer of spectrophotometer Gravimetry –A precipitate is formed, separated and weighed –A precipitate is formed and kept in suspension. Its ability to scatter light is mesured by a nephelometer or spectrophotometer Electrochemistry –An electrode which responds to the concentration of a particular species of ion is placed in the sample.

90 Practical Considerations Only the simplest tests (alkalinity, hardness, chorine) can be done without a lot of trouble and expense –Of limited but sufficient accuracy for brewing More accurate measurements, as with pH, require calibration with standards –Chemistries age. Old chemistries can be used past expiration dates but standards must be employed –Much more involved than tolerability unless this is part of the hobby (or commercial operation) 89

91 90 Part VII Synthesizing Water With Desired Profile

92 91 Where Do I Get Profiles? From textbooks, friends, articles, the internet, the ones on the handout CD ROM –Caution - not all profiles are physically realizeable. Reporting, measurement, interpretation errors Reporting of average values –Simple check: add up all ion concentrations, specify a pH and calculate net electronic charge Must be close to 0 (imbalance of a few %) Easily done with spreadsheet on CD ROM Same as for evaluating quality of water reports You cant get a good approximation to an unrealizeable profile!

93 92 Target Profile: Burton on Trent

94 93 Base Water Deionized (DI) water (distilled, ion exchanged but not by home water softener!) represents blank piece of paper –RO water is a decent approximation to DI Other water: can increase an ion concentration easily but not decrease it –Dilution with DI/RO water –Bicarbonate can be removed to some extent Takes calcium and magnesium with it. Modern municipal supplies generally represent a decent starting point

95 94 Source Water McLean Well

96 95 Approach to Synthesis Simply add anything that is deficient! –Catch: You must add salts. Ratio of calcium to chloride in CaCl 2 is fixed! (100mg Ca:35mg Cl) –Nevertheless you can do quite well using a few common salts NaCl, MgSO 4.7H 2 0, NaHCO 3 Source - grocery or drugstore –Table salt (dont use iodized!), epsom salts, baking soda CaSO 4.2H 2 0, CaCO 3, CaCl 2.2H 2 O Source homebrew supply shop –Gypsum, (precipitated) chalk, calcium chloride –If using carbonate, bicarbonate or changing alkalinity you will need acid This can be CO2 Sulfuric or Hydrochloric (not recommended: FCC, USP, safety) –Math is nettlesome: successive approximations by manipulation of salt addition amounts until combined error in ion concentrations is small –Excel Solver to the rescue! Set up the problem and let the Solver do the work. FCC = Food Chemicals Codex i.e. approved for use in food for human consumption USP = United States Pharmacopoeia i.e. approved for use in drugs for humans

97 96 Adding an Ion from a Salt Gypsum is CaSO4.2H2O GMW Each millimole of mg contains 40 mg of Ca ++ and 98 mg of SO 4 -- To add, for example, 60 mg/L Ca ++ would require 60/40 = 1.5 mMol = mg gypsum for each litre treated –And you are also adding 1.5*98 = 147 mg/L SO 4 -- like it or not. To add 250 mg/L sulfate use 250/98 = 2.55 mMol = 440 mg/L –And you are also adding 2.55*40 = 102 mg/L Ca ++ like it or not. Spreadsheet does all this math for you. Compromise necessary because of fixed relative amounts of ions in salts If target is reasonable, spreadsheet can do a fairly good job and its a lot easier than doing the math yourself

98 97 Synthesis Portion of Spreadsheet Specify salt additions here Resulting ion concentrations Relative importance in computing error

99 98 Water Worksheet Summarized Three parts (two identical) –These two accept your inputs of pH, alkalinity(as CaCO 3 or mEq), hardness (as CaCO 3 or mg/L), other ion content, temperature (°F or °C) –Compute balance, residual alkalinity, ionic strength, carbo species ratios and fractions Must have balanced target; should have balanced source –One on left is for source water –One on right is for target water profile –Middle part is for synthesis of target from source Manually indicate the amount of each salt or acid you want to try Check errors (differences between desired and realized) Adjust until close enough for government work Better still: Let Excel Solver do this for you Detailed instructions on Sheet 2 of spreadsheet

100 99 More on Acid Requirements If you use NaHCO 3 and/or CaCO 3 in a synthesis pH will most probably shift and CaCO 3 probably wont dissolve –Acid is required to set pH to desired value and dissolve CaCO 3 –If you have used these to match alkalinity and then intend to decarbonate, save yourself the trouble - synthesize for stylistic ions only Much will probably precipitate when water is heated in HLT I do not recommend the use of strong mineral acids for safety reasons That leaves CO 2. Add salts and stir. Water will be cloudy as CaCO 3 will be in suspension Bubble CO 2 through water until it clears and pH is about right - this may take some time (hours). –Pressure helps dissolve CO 2 - put salts in Corny keg, pressurize, agitate –Target pH not that critical. Will go where it wants to in HLT, mashtun

101 100 Part VI Treatment

102 101 At Water Treatment Plant Depending on source, strong oxidants may be used to burn off flavors, aromas –Chlorine, potassium permanganate Mix with salt of trivalent metal (Fe, Al) –Forms hydroxide gel which is allowed to settle –Drags down particles (silt, bacteria, viruses) with it Decant, filter (may include active carbon)… Adjust alkalinity, hardness, pH –Same way we do! Add acids, lime, salts to desired profile –Mostly for protection of distribution system –Set to near saturation pH (small amounts of lime precipitated) Inject chlorine and/or ammonia and/or ozone Send to distribution system

103 102 At Home - Well Wound filters remove particulates If iron is present Aeration/sand filter (or greensand filter) If water is acidic (subterranean CO 2 ) run through limestone (neutralizer). Prevents corrosion; increases hardness and alkalinity. Softener - Dont use for brewing water! –Ion exchange resin loaded with Na + (sometimes K + ) –Replaces Ca ++, Mg ++ with Na + (sometimes K + ) –Backwash with brine, NaCl (or KCl) recharges medium. Replaces Na + (or K + ) while Ca ++, Mg ++ go down drain. Removes beneficial hardness and replaces with useless Na + (or K + ) Reverse Osmosis (RO) units force water through membrane with small pores removing most ions (95-99%) Activated carbon filter: removes organics, mustiness… Anion/Cation ion echanger (see next slide)

104 103 At Home - City Water Wound filters remove particulates Softener - Dont use for brewing water! Activated carbon filter: removes chlorine, chloramine, organics –Required if RO unit is installed - HOCl, H 2 NCl poison membrane –Available as whole house or at sink installations Reverse Osmosis (RO) units force water through membrane with small pores removing most ions (95-99%) Cation/Anion exchanger: –Swaps H + for all cations, (OH) - for all anions. Result: DI water. –Brita filters in this class (also contain silver as Ag + is bacteriostatic)

105 104 Decarbonation/Softening Goal is decarbonation (reduction of alkalinity). Softening is the price that usually must be paid. –Ca HCO > CO 2 + CaCO 3 + H 2 O Calcium is removed but only to extent of bicarbonate e.g water with alkalinity of 100 ppm as CaCO 3 and hardness of 200 ppm as CaCO 3 precipitates all (theoretically) its bicarbonate and half its calcium –Decarbonation limit practially about 50 ppm as CaCO 3 Calcium so precipitated is called temporary hardness Remaining calcium is called permanent hardness –Ca(OH) 2 + Ca HCO > 2H 2 O + 2CaCO 3 This is actually neutralization of the acid HCO 3 - with the base Ca(OH) 2 which suggests procedure (next slide) Decarbonation limit practially about 50 ppm as CaCO 3 –Ca HCO HCl ----> 2CO 2 + Ca Cl - + 2H 2 O No softening: temporary (carbonate hardness) converted to permanent (non carbonate hardness) - no decarbonation limit heat

106 105 Lime Decarbonation Calculate amount of lime required –CaO (quick lime) + H 2 O --> Ca(OH) 2 (slaked lime) + heat Pickling lime is slaked. Available in canning section of supermarket –1 mMol of slaked lime (74 mg) treats 2 mEq bicarbonate (122 mg or 100 ppm as CaCO 3 alkalinity) Ca(OH) 2 + Ca HCO > 2H 2 O + 2CaCO 3 All added calcium precipitates. No hardness increase (theoretically) –DeClerck recommends treating trial batches with this amount and ±10%. Then use dose that gave best results Add to 2/3 the water to be treated –Wait for Mg(OH) 2 to precipitate and decant if Called (split treatment). Only necessary if Mg is to be reduced Excess lime with only 2/3 water raises pH to where Mg(OH) 2 forms –Titrate back to pH 8 or so with remaining volume –Allow to settle and decant

107 106 Iron Fe ++ (clearwater iron) is soluble Fe(OH) 3 is insoluble (ugly brown) gel Approach to treatment is, thus, to oxidize any Fe ++ to Fe +++, at higher pH Fe(OH) 3 gel forms. Filter gel –4Fe H 2 O + O 2 +8(OH) - --> 4Fe(OH) 3 (gel) –Gel gets caught by sand. Backwash to dispose –Aeration supplies oxygen and sweeps CO 2 raising pH, increasing (OH) - Aeration by spraying, sparging with air, pouring back and forth then pouring through clean sand works Commercial units inject air and then pass through sand bed - similar construction as neutralizers, softeners Manganese greensand oxidizes Fe ++ (and Mn ++ and S - ) and traps gels –Its Mn(IV) that does job. Recharge with Mn (VII) i.e. KMnO 4

108 107 Chlorine/Chloramine These must be removed from brewing water –Form chlorphenolics with plastic, bandaid flavor at ppb level. Water treatment plants have bubbled chlorine gas into product for years - significant public health factor –H 2 O + Cl 2 H + + Cl - + HOCl Uncharged hypochlorous acid slips through bacterial cell wall disabling key enzymes - strong oxidizing agent –Standing, boiling, sparging reverses reaction removing chlorine More recently, ammonia is added after chlorination –NH 3 + HOCl --> H 2 O + H 2 NCl : Monochloramine Less likely to produce Trihalomethanes (THMs) More stable (persistent) in distribution system More persistent when you try to remove it

109 108 Removing Chloramine Boiling is effective but it takes an hour or more Granulated activated charcoal (GAC) filters are effective but make sure contact time is long enough –Limit flow rate –If you can smell it, it broke through Simplest treatment: 1 Campden Tablet for 20 gal. –Crush and suspend in a small amount of water, stir in.

110 109 Part -XX Comparison Beer

111 110 …and why was Burton Built on Trent? …well water drawn from the evaporite-rich Permo-Triassic sandstones outside of town It must make good beer because water doesnt taste very good –High sulfate accentuates hop character, stabilizes beer biologically (IPA) I have 7 profiles for Burton (all on handout CD). One which balances at pH 6.6 (i.e. a reasonable one) and shows: –Alkalinity: 182 ppm as CaCO 3 –Calcium Hardness: 878 ppm as CaCO 3 –Mg Hardness: 99 ppm as CaCO 3 –Residual Alkalinity - 83 ppm as CaCO 3 (pH Shift -0.17) –Sulfate: 820 mg/L –Chloride: 16 mg/L –Sodium: 44 mg/L This one was implemented with well water, baking soda, table salt (not iodized), epsom salts, gypsum, precipitated chalk and CO bbl batch brewed using Maris Otter, some Munich, 1058 London ale, Sterling, US Kent Goldings and EKS °P Same beer brewed with untreated well water A. E. Houseman, Shropshire Lad

112 111 Brewing

113 112 Fermentation

114 113 Tasting Look for differences in –Esters (aroma & flavor): Fruit, berry… –Yeast aroma: Bready? –Hops: (aroma & flavor):bitterness, sharpness, coarseness, fruity –Sweetness –Mouthfeel: viscosity, mellowness, astringency/dryness, rough/smooth, bite Is one beer better than the other? –If so and its the Burtonized one is it enough better that its worth the trouble?

115 114

116 115 Further Reading Basic inorganic chemistry text The articles on the handout CD Palmer, John, How to Brew Hardwick, W. A. (Ed.) Handbook of Brewing De Clerck, J. A Textbook of Brewing (no ISBN! – get it from Siebel) Noonan, G, New Brewing Lager Beer Foster, Terry, Pale Ale 2 nd Edition Eaton, et al. Eds. Standard Methods for the Examination of Water and Wastewater


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