Brewing Water 6 October 2008 A J de

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

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 p. H 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 1

Approach • Water chemistry is intricate and detailed if not complex • In a couple of hours I can only skim the surface – There won’t 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 won’t 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 2

There are Two Aspects to Brewing Water • I: Water chemistry has great influence on mash p. H thus great influence on nature of the beer – Full understanding of this requires knowledge of acidbase 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 3

Your Goals • Understand – Relationship between beer and water it’s made from – Fundamentals of chemistry related to brewing water • Atoms, molecules, ions, moles, equivalents, acids, titration… – p. H, 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 p. H of your mash Establish an approximation to a desired ion profile 4

Quotations • “Wine is made by farmers. Beer is made by engineers. ” (? ) • “A distinction is frequently drawn in the industry between 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 de. Clerck • “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 Du. Garm 5

Quotations II • Water contains three ions which influence the p. H of wort: bicarbonate, calcium and magnesium. The bicarbonate ion has a p. H raising effect, the other two lower it. The p. H lowering effect of magnesium ions is only half that of calcium ions. Depending on the ratio of the water’s content of bicarbonate on the one hand calcium and magnesium on the other, the p. H 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 p. H 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 p. H raising effect of the water. – Paul Kohlbach, Die Einfluss des Brauwassers auf das p. H von Würze und Bier, Monatsschrift für Brauerei, Berlin, Mai 1953 – Whole paper is on CD. Read it! 6

Topics • Part 0: Beer and Water • Part 1: Fundamentals of Chemistry • Part 2: Carbon Dioxide, Water, Limestone, p. H, 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 7

Handout CD Contains… • A copy of this presentation • Translation of Paul Kohlbach’s seminal paper (1953) • A set of slides from a lecture given at De. Clerck 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. 8

Part 0 Overview - Beer and Water 9

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 10

The First of the Two Aspects • Bicarbonate is a base - it’s alkaline – It raises mash p. H ~ malt enzymes become less effective – It must be neutralized or removed (so p. H 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 p. H. 11

Hardness & Alkalinity for Several Cities Bad OK Good OK RA = Alkalinity - (Ca_hardness + Mg_hardness/2)/3. 5 12

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

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 14

Atoms • Smallest particle of elemental matter with nucleus of positively charged protons and uncharged neutrons… – … of mass ~1. 673 E-24 grams (protons and neutrons slightly different) • Surrounded by negatively charged electrons – – – With mass 0. 000911 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 we’ll 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); 6 p + 8 n ~ 14 C (radioactive) 15

Chemical Symbols • Each element (atom type) is represented by a symbol – It’s 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: – Na. Cl ~ Sodium chloride HCl ~ Hydrochloric Acid Ca. Cl 2 ~ Calcium chloride H 2 CO 3 ~ Carbonic acid Ca. CO 3 ~ Calcium Carbonate Ca. SO 4. 2 H 2 O Calcium Sulfate with 2 waters of hydration. – Subscript indicates number of atoms in molecule • 1 Molecule of Ca. CO 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 16

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]+1 e-): 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]+7 e-): Cl + e- --> Cl- Ion • ([Ne]+8 e- = [Ar]) – Calcium ([Ar]+2 e-): Ca --> 2 e- + 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) 17

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]+4 e– Hydrogen (H) has 1 electron: 1 e– If carbon shares the electrons from each of 4 hydrogen atoms it completes its outer (valence) shell : • [He] + 4 e-(shared from hydrogens) ~ [Ne] – Each hydrogen shares one of carbon’s electrons • 1 e- + 1 e- (shared from carbon) ~ [He] – CH 4 is the gas methane • Na gives e- to Cl. Na+ attracts Cl- --> Na. Cl • Atoms so combined are called molecules the constituents of compounds. 18

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 Ammonia (base): NH 3 + H+ --> NH 4+ Sulfuric Acid: H 2 SO 4 --> H+ + HSO 4 Hydrochloric Acid: HCl --> H+ + Cl- Bicarbonate ion Ammonium ion Bisulfate ion Chloride ion • Ions can do this too and become doubly ionized or un-ionized – Bicarbonate ion: HCO 3 - --> H+ + CO 3 -- Carbonate ion – Bicarbonate ion: HCO 3 - + 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. 19

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++ + 2 HCO 3 - --> 2 Ca. CO 3 + 2 H 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. 20

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. 023 E+23 called Avogadro’s Number. – Avogadro’s number of Daltons = 1 gram – Avogadro’s number of anything (atoms, molecules, ions, electrons, rutabagas, even furry blind subterranean mammals) is called one 21 mole

Gram Molecular Weights ~ Weight of 1 mole • • Hydrogen: 1 proton. 1 mole should weigh about 1 gram. Actual GMW 1. 00794 Oxygen: 8 protons, 8 neutrons. 1 mole should weigh about 16 grams. Actual value 15. 9994 Calcium: 20 protons, 20 neutrons. 1 mole should weigh about 40 grams. Actual value 40. 078 Ca(OH)2: 38 protons, 38 neutrons. 1 mole should weigh about 74 grams. Actual GMW 74. 093 HCO 3 -: 31 protons, 30 neutrons. 1 mole should weigh about 61 grams. Actual GMW 61. 03 Thus 1 molecule of Ca(OH)2 reacting with 2 HCO 3 - ions implies that 6. 023 E 23 (1 mole = 74. 093 grams) of Ca(OH)2 will react with 12. 046 E 23 (2 moles = 122. 06 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 m. Mol of Ca(OH)2 weighing 74. 093/2 = 37. 046 mg per liter. 22

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 61. 03 means 61. 03 grams has a charge of 1 mole of (-) charges. Equivalent weight = 61. 03. Doubly charged Ca++: 20 protons, 20 neutrons. GMW 40. 078 means 40. 078 grams carries 2 moles of (+) charge. 20. 039 grams carries 1 mole. Equivalent weight = 20. 039 Equivalent weight = gram molecular weight divided by charge. Alkalinity (HCO 3 -) and hardness (Ca++, Mg++) are often expressed in milliequivalents per liter (m. Eq/L sometimes called m. Val/L or just m. Val). Sometimes given as 50 times m. Eq/L - called parts per million as Ca. CO 3 – This is seen a lot. Note: 1 ppm ~ 1 mg/L (as water weighs ~ 1 kg/L) 100 mg 1 m. Mol 44 mg 1 m. Mol 18 mg 1 m. Mol 122 mg 2 m. Mol 40 mg 1 m. Mol Ca. CO 3 + CO 2 + H 20 --> 2 HCO 3 - + Ca++ 2 m. Eq 100 ppm as Ca. CO 3 23

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 = 11. 36 Mol ~ 11. 36 Eq (OH) • H+ + (OH)- --> H 2 O Need 11. 36 Eq H+ • Sulfuric Acid MW 98: H 2 SO 4 --> 2 H+ + SO 4 -– 11. 36/2 Mol H 2 SO 4 yields 11. 36 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 = 0. 806 kg) go down drain (wrong on CD) • Hydrochloric Acid MW 36. 46: HCl --> H+ + Cl– 38% HCl solution (23 Baume) is 12. 29 Normal meaning it contains 12. 29 Eq H+ per litre. Therefore need 11. 36/12. 29 = 0. 917 L of 38% HCl – 664 g Na. Cl (table salt) goes down drain • Add acid to solution until p. H neutral rather than relying on calculation 24

Another Example Calculation • Water tests 3 mg/L available chlorine (from chloramine). How much potassium metabisulfite (K 2 S 2 O 5 MW 222. 32) is required to treat 20 gal (76 L) – 2 K+ + S 2 O 5 -- + 2 H 2 NCl + 3 H 2 O --> 2 K+ + 2 SO 4 -- + 2 H+ + 2 Cl- + 2 NH 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 = 0. 0846 m. Mol/L requiring 0. 0423 m. Mol/L metabisulfite and producing 0. 0846 m. Mol/L sulfate, hydrogen, chloride and ammonium ions. – The GMW of potassium metabisulfite is 222. 32 mg/m. Mol so we need 9. 4 mg/L or 714 mg total (one lot of Campden tablest we measured weighed 695 mg) – The hydrogen ions, 0. 0846 m. Eq/L represent a reduction in alkalinity of 50 times this or 4. 2 ppm as Ca. CO 3. – As each bound chlorine atom is converted to a chloride ion the chloride level will increase by 3 mg/L – 0. 0846 m. Mol/L * 96 mg/m. Mol ~ 8. 12 mg/L increase in sulfate (Pils brewers take note) – 0. 0846 m. Mol/L*18 mg/m. Mol ~ 1. 5 mg/L increase in ammonium ion (your yeast will love it) 25

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

Carbon Dioxide: CO 2 MW 44. 01 • Spewed by volcanoes • Taken up by plants -> sugar, starch… oxygen light – 6 CO 2 + 6 H 2 O ------> C 6 H 12 O 6 + 6 O 2 • Released by carbohydrate oxidation (including respiration, fermentation, decay…) – Cn. H 2 n. On + n. O 2 --> n. CO 2 + n. H 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. 0003 Atm ~ 0. 3 h. Pa) • 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). 27

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. 28

Carbonic Acid MW 62. 03 • 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 p. H (at brewing p. H it is basic) – In reverse, CO 3 -- takes up a proton to form HCO 3 -- is a base • …which can coalesce with calcium ion to precipitate chalk – CO 3 -- + Ca++ <--> Ca. CO 3 (only slightly soluble) 29

Calcium Carbonate MW 100. 087 • Ca++ + CO 3 -- --> Ca. CO 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 – Ca. CO 3 + H 2 O + CO 2 --> Ca. CO 3 + H 2 CO 3 --> 2 HCO 3 - + Ca++ – Surface and ground water are hard & alkaline – Cave formation: underground pa. CO 2 much higher (hence more carbonic) because of respiring bacteria 30

Law of Mass Action • In any reaction m. A + n. B <--> k. C + j. D • {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} = p. K • If A + B <--> C (underscore ~ precipitation) then – – {A}{B} < Ks (solubility product) No precipitation occurs {A}{B} > Ks supersaturated. Precipitation usually occurs {A}{B} = Ks saturated. No precipitation p{A} + p{B} = p. Ks at saturation 31

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

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

- 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 CT = x(1 + r 1 r 2) =xd • CT = 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 34

Distribution of carbo species p. H s p. K 1 6. 38 p. K 2 10. 35 Alkalinity is defined as the number of m. Eq of acid required to change the p. H of a sample from its p. H at the source (p. Hs) to p. H 4. 3 35

Alkalinity • Definition: the number of m. Eq of acid required to change p. H of a sample to a reference p. H (usually p. Hr = 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 -p. Hr m. Eq/L Acid require to neutralize (OH)- alk = CT(f 1, r - f 1, s + f 3, s- f 3, r) + (1000)10(p. Hs-p. Hr) + (1000)10(p. Kw-p. Hr-p. Hs) • • • r ~ reference p. H, s ~ sample p. H, p. Kw = 14 Units: m. Eq/L (that’s why the factor of 1000 is there) CT = total mmol/K carbonic, bicarbonate, carbonate Equation can be solved for CT if alk, p. Hr and p. Hs are known Thus choice of p. Hr is somewhat arbitrary 36

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

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

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 p. H – 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 Ca. CO 3 – Make charts like on next slide • It is what is behind the spreadsheet on the CD 39

CO 2 Over Water in Equilibrium with Ca. CO 3 40

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

p. H • Søren Peter Lauritz Sørenson (1868 -1939) – Worked at Carlsberg Laboratory – Studied amino acids, proteins enzymes – Their behaviour (total electric charge) depends on hydrogen ion concentration (mechanism we’ve been discussing). – Sought convenient scale for specifying {H+} (1909) – Called it pondus (L. a weight) hydrogenii i. e. p. H = -log 10{H+} – For pure water {H+} = 10 -7 Mol/L thus p. H = 7 – For. 001 N acid {H+} = 10 -3 Mol/L thus p. H = 3 • p. H < 7: Acid, sour, beer, wine, soda (phosphates), vinegar, lemon, lime (citrus), sauerkraut, sour cream, kimche • p. H ~ 7: Neutral, water, blood, brine • p. H > 7: Base, bitter, lye, lime (slaked), soda ash 42

Importance of p. H in Brewing • Necessary to calculate carbo species distribution in water • As p. H 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 p. H 5. 2 -5. 7 • Proper charge distribution on proteins (chains of amino acids) in boil (iso-electric point~ net charge 0) enhances coagulation H+ H 3 N+CRHCOO H p. H 1 Q = 1 H+ H 3 N+CRHCOO p. H 6 Q = 0 H 2 NCRHCOO p. H 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 43

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

p. H Measurement • Originally with dye which changes color at particular p. H – “Litmus Test” from a lichen (red < 7, blue >7) – Phenolpthalein, bromcresol red, methyl orange (4. 3) … • Electronically: potential developed across specially prepared (delicate) glass bulb dependent on p. H 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 p. H change • Depends on temperature - temperature compensation essential • Note: p. H also changes with temperature (because p. K’s 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 p. H 45

Part III Adding Phosphate, Residual Alkalinity 46

Phosphoric Acid Chemistry • Same as carbonic except – The oxide is a solid: P 2 O 5 + 3 H 2 O --> 2 H 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 4 - --> 2 H+ + HPO 4 -- --> 3 H+ + PO 4 -- • Three (not the same as carbonic) p. K’s (2. 12, 7. 21, 12. 67), three r’s, three f’s. • 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 • 3 Ca++ + 2 Na 3 PO 4 ---> Ca 3(PO 4)2 + 6 Na+ – And why malt phosphate lowers p. H of hard water • Net reaction releases protons (hydrogen ions) - later slide 47

Phytic Acid from Malt 48

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 p. H. • Paul Kohlbach observed that 3. 5 m. Eq of Ca++ or 7 m. Eq Mg++ “neutralize” 1 m. Eq alkalinity – Neutralize here means that the p. H of a mash with all alkalinity neutralized has same p. H 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 m. Eq/L or ppm as Ca. CO 3. – Also noted 0. 085 p. H shift for each m. Eq/L (50 ppm) of RA 49

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 Ca. CO 3 corresponding to p. H shift increments of 0. 085 • Above heavy line (RA = 0) p. H will be higher than distilled water mash, below it, p. H will be higher • RA < 50 generally OK (dotted line) 50

RA Chart 51

Use of Chart - Example • Edinburg (Edn 2): Alk 180, Hard_eff 340, RA 85, p. H ~ 5. 89 is too high • Reduce alkalinity by 180 - 100 = 80 to get to RA ~ 0 and p. H ~5. 75 – Add 80/50 = 1. 6 m. Eq/L acid (e. g. HCl, H 2 SO 4) – Decarbonate water. Can get to approximately 50 ppm as Ca. CO 3, RA ~ 35, p. H 5. 69 • Could also get to this RA by adding (180 -50)/50 = 2. 6 m. Eq/L acid • Add (620 - 340)/50 = 5. 6 m. Eq/L hardness – 5. 6 m. Eq/L Ca++ ~ 2. 8 m. Mol/L Ca. SO 4. 2 H 20 ~ 482 mg/L gypsum 52

Carbo + Phosphate System 10 Ca+2+12 HCO 3 - + 6 H 2 PO 4 - + 2 H 2 O -> Ca 10(PO 4)6(OH)2 + 12 CO 2+ 2 H+ +12 H 2 O 53

Demonstration • Prepare phosphate buffer from 40 m. Mol/L KH 2 PO 4 • Add Na 2 HPO 4 to p. H 5. 92 – Phosphate buffers very commonly used to control p. H in laboratory • Simulates phosphate distribution in distilled water mash • Add strong Ca. Cl 2 solution drop by drop and observe p. H • p. H 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, p. H drop would no be so dramatic as some of the H+ released would go to neutralize it. 54

Part IV Water Reports 55

Water Report Key Parameters 1 st Aspect • Alkalinity – Measure of acid required to lower sample p. H to 4. 3 ~ buffering capacity of water – Indicator of amount of acid (from any source) required to establish proper mash p. H (5. 2 -5. 6) – 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 it’s alkalinity (reaction with malt phosphate) • p. H – Permits calculation of ion balance (quality check on report) – Permits calculation of amount of bicarbonate from alkalinity – Otherwise, not really that important 56

Water Report Key Parameters 2 nd Aspect • Sulfate – Large effect on the way hops are perceived • High value for assertive, dry hop flavor • Low (15 mg/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 >300 mg/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. 3 mg/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) 57

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

Magnesium • Part of hardness - half as effective as Calcium in RA reduction (m. Eq for m. Eq). • 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 59

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, … 60

61

April: 50*32. 5/20 (Ca) + 50*8. 2/12. 15 (Mg) = 80 + 33. 7 = 113. 7 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. 62

63

Imbal =100*(1. 4 -1. 1)/(1. 4+1. 1)=12% 64

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 p. H calculation gets a bit nettlesome • Must calculate CT, r’s, f’s – Spreadsheet on CD takes care of all this for you • Full instructions for use on 2 nd sheet. 65

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

Full set of measurements from 6341 Georgetown Pike well 30 Oct 2008 67

Worksheet for 30 Oct 08 Analysis 68

Part V Testing Water 69

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 p. H 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 www. hach. com or aquarium supply company – These things are getting expensive! 70

p. H (Water Analysis Perspective) • Need to measure/detect “end point” p. H 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 p. H meter. Keep it clean and wet. Don’t stick it into hot wort or mash! 71

p. H Meter • Voltage E = E 0 + (RT/F)ln{H+} is developed across special glass membrane – E 0 is voltage developed when {H+} = 1 – R (Bolzman’s) and F (Faraday’s) are constants – T is temperature (Kelvins) • E = E 0 + 2. 303(RT/F)log{H+} = E 0 - S*p. H • You (or the meter), must know E 0 and S in order to determine p. H = (E 0 –E)/S • This is where standard buffers come in – Placing the meter in 2 solutions of known p. H and at known temperature allows meter to calculate S and E 0 • Thereafter meter can adjust readings for temperature response of electrode (ATC) • But not, e. g. shift in wort p. H from kettle to room temperature! 72

Alkalinity alk = CT(f 1, a- f 1, i+ f 3, i- f 3, a) - 1000(10 -p. Ha -10 -p. Hi +10 p. Hi-p. Kw-10 p. Ha-p. Kw) • • Defined as the number of m. Eq/L of acid required to lower p. H of water sample from its initial value, p. Hi, to a reference p. H, p. Ha is part of definition of alkalinity and is usually 4. 3 in brewing – May be based on equivalence: CTf 2, a ≈ (1000)10 -p. Ha – Analyst should report p. Ha. If he didn’t use 4. 3 – Important because you will solve for CT in report quality checking, synthesis • • • Units of m. Eq/L (hence factor of 1000). Multiply by 50 for ppm as Ca. CO 3. CT = total millimoles/L carbonic, bicarbonate, carbonate in sample f s subscripted i refer to fractions at p. Hi f s subscripted a refer to fractions at p. Ha Kw is dissociation constant of water (p. Kw = 14 @ 20°C) Equals sum of acid required to – Convert initial fractions to fractions (mostly carbonic) at p. Ha – Increase hydrogen ion content to 10 -p. Ha – Decrease (by neutralizing to H 2 O) hydroxyl ion concentration to 10 p. Ha-p. Kw 73

Alkalinity II - Definition: The number of m. Eq of acid which must be added to a liter of water to bring p. H to 4. 3 (IOW, to convert most carbonate and bicarbonate to carbonic). Multiply by 50 for ppm as Ca. CO 3. - Measured by titration (addition of small amounts of acid until p. H 4. 3 is reached and reporting total used) - A rough indication of the amount of acid needed in the mash per L water Example sample p. Hi Where you’d Like to be in Mash tun Where you go during titration 74

Alkalinity - Procedure • Add an indicator (e. g. methyl orange or bromcresol greenmethyl red) or a p. H electrode to 100 m. L sample • Using a buret (conventional, digital, automatic, eyedropper, syringe…) add 0. 1 N (. 1 m. Eq/L) acid (usually sulfuric) to sample until indicator turns color or p. H 4. 3 is reached – Other endpoint p. H values can be used • Report total number of m. L acid used and endpoint p. H – Multiply by 50 for ppm as Ca. CO 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 75

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

++ ++ 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 m. L of sample with buffer to set p. H for sharp end point • Titrate with a standardized strength chelating agent (EDTA) until the sample changes from red to blue. • Report the number of m. L chelant used (it has been calibrated to a convenient number of m. Eq or ppm or grains or d. H (German degrees) etc. hardness per m. L) • This gives the total hardness (sum Ca + Mg) • Kits available: Hach HA-71 A $48. 25 (100 tests) – Test tube/bottle, EDTA, Indicator, buffer, 20 ppm res. 77

Calcium Hardness • Remove Mg++ from water by raising p. H (add suitable buffer) – Mg++ + 2(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-4 P Total and Calcium Hardness $65. 05 (100 tests) 20 ppm as Ca. CO 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). 78

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. 79

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 Hg. Cl 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- ---> Hg. Cl 2 + 2 SCN- – Add ferric ion solution • 3 SCN- + Fe+++ ---> Fe(SCN)3 (red orange) – Measure depth of color formed with photometer. • Note: Nasty mercury salts used in both these - Hg waste 80

Sulfate • Barium sulfate is insoluble, Barium chloride is soluble. • Add barium chloride to sample. Barium coalesces with sulfate to form insoluble Ba. SO 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. 81

Sodium • No practical chemical method • Atomic Absorption/Atomic Emission Spectrophotometry – Sample is vaporized into flame. Optical absorption (or emission) at 589. 6 nm is measured. • Ion Selective Electrode (ISE) – Similar to p. H 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 p. H). – 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 82

Sodium - Multiple Additions • m. V = U 1 + Unlog{Na+} – U 1 = 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… m. L of sodium standard solution of known strength S mg/m. L. Then… m. V 0 = Unlog(v 0{Na+}0) + U 1 m. V 1 = Unlog(v 0 {Na+}0 + S(v 1)/(v 0 + v 1)) + U 1 m. V 2 = Unlog(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, Un, and U 1 • Math is not basic (iterative non linear mmse estimation) but easily handled in a laptop • • – Excel Solver can do it! 83

Sodium ISE Recording Example 84

Analysis of Assymptotic m. V Readings from Previous Slide Slope = 48. 4336, Intercept = -148. 0979 m. V, Concentration = 5. 8632 ± 0. 0255 mg/L; rmse = 0. 1015 m. V after 88 iterations. Un DOP = 4. 74 m. V/decade/m. V; U 0 DOP = 7. 57 m. V/m. V; Concentration DOP = 4. 48 mg/L/m. V 85

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. 86

Other Ions • There are tests for dozens of other ions – Fe(II), Fe(III), Cu, Mn, Zn, NO 2, NO 3, K, Al, Si. O 2, NH 3… all based on similar principals – Kits are available for many (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, don’t 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 87

Summary of Measurement Techniques • Titration – Addition of reagent of calibrated strength until an end point (color change, particular p. H…) 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. 88

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 p. H, 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

Part VII Synthesizing Water With Desired Profile 90

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 p. H 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 can’t get a good approximation to an unrealizeable profile! 91

Target Profile: Burton on Trent 92

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 93

Source Water Mc. Lean Well 94

Approach to Synthesis • Simply add anything that is deficient! – Catch: You must add salts. Ratio of calcium to chloride in Ca. Cl 2 is fixed! (100 mg Ca: 35 mg Cl) – Nevertheless you can do quite well using a few common salts • Na. Cl, Mg. SO 4. 7 H 20, Na. HCO 3 Source - grocery or drugstore – Table salt (don’t use iodized!), epsom salts, baking soda • Ca. SO 4. 2 H 20, Ca. CO 3, Ca. Cl 2. 2 H 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 CO 2 • 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 95

Adding an Ion from a Salt • Gypsum is Ca. SO 4. 2 H 2 O GMW 172. 14 • Each millimole of 172. 14 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 m. Mol = 258. 2 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 m. Mol = 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 96 and it’s a lot easier than doing the math yourself

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

Water Worksheet Summarized • Three parts (two identical) – These two accept your inputs of p. H, alkalinity(as Ca. CO 3 or m. Eq), hardness (as Ca. CO 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 98

More on Acid Requirements • If you use Na. HCO 3 and/or Ca. CO 3 in a synthesis p. H will most probably shift and Ca. CO 3 probably won’t dissolve – Acid is required to set p. H to desired value and dissolve Ca. CO 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 Ca. CO 3 will be in suspension • Bubble CO 2 through water until it clears and p. H is about right - this may take some time (hours). – Pressure helps dissolve CO 2 - put salts in Corny keg, pressurize, agitate – Target p. H not that critical. Will go where it wants to in HLT, mashtun 99

Part VI Treatment 100

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, p. H – Same way we do! Add acids, lime, salts to desired profile – Mostly for protection of distribution system – Set to near saturation p. H (small amounts of lime precipitated) • Inject chlorine and/or ammonia and/or ozone • Send to distribution system 101

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 - Don’t use for brewing water! – Ion exchange resin loaded with Na+ (sometimes K+) – Replaces Ca++, Mg++ with Na+ (sometimes K+) – Backwash with brine, Na. Cl (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 echanger (see next slide) 102

At Home - City Water • Wound filters remove particulates • Softener - Don’t 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) 103

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

Lime Decarbonation • Calculate amount of lime required – Ca. O (quick lime) + H 2 O --> Ca(OH)2 (slaked lime) + heat • Pickling lime is slaked. Available in canning section of supermarket – 1 m. Mol of slaked lime (74 mg) treats 2 m. Eq bicarbonate (122 mg or 100 ppm as Ca. CO 3 alkalinity) • Ca(OH)2 + Ca++ + 2 HCO 3 - ----> 2 H 2 O + 2 Ca. CO 3 • All added calcium precipitates. No hardness increase (theoretically) – De. Clerck 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 p. H to where Mg(OH)2 forms – Titrate back to p. H 8 or so with remaining volume – Allow to settle and decant 105

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 p. H Fe(OH)3 gel forms. Filter gel – 4 Fe++ + 2 H 2 O + O 2 +8(OH)- --> 4 Fe(OH)3 (gel) – Gel gets caught by sand. Backwash to dispose – Aeration supplies oxygen and sweeps CO 2 raising p. H, 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 – It’s Mn(IV) that does job. Recharge with Mn (VII) i. e. KMn. O 4 106

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 107

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. 108

Part -XX Comparison Beer 109

“…and why was Burton Built on Trent? ” A. E. Houseman, Shropshire Lad • • “…well water drawn from the evaporite-rich Permo-Triassic sandstones outside of town” It must make good beer because water doesn’t 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 p. H 6. 6 (i. e. a “reasonable” one) and shows: – – – – • • • Alkalinity: 182 ppm as Ca. CO 3 Calcium Hardness: 878 ppm as Ca. CO 3 Mg Hardness: 99 ppm as Ca. CO 3 Residual Alkalinity - 83 ppm as Ca. CO 3 (p. H 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 2. 1. 5 bbl batch brewed using Maris Otter, some Munich, 1058 London ale, Sterling, US Kent Goldings and EKS - 12. 7°P Same beer brewed with untreated well water 110

Brewing 111

Fermentation 112

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 it’s the Burtonized one is it enough better that it’s worth the trouble? 113

114

Further Reading • • Basic inorganic chemistry text The articles on the handout CD Palmer, John, How to Brew 978 -0 -937381 -88 -5 Hardwick, W. A. (Ed. ) Handbook of Brewing 0 -8247 -8908 -3 De Clerck, J. A Textbook of Brewing (no ISBN! – get it from Siebel) Noonan, G, New Brewing Lager Beer 0 -937381 -46 -2 Foster, Terry, Pale Ale 2 nd Edition 0 -937381 -69 -1 Eaton, et al. Eds. Standard Methods for the Examination of Water and Wastewater 115