Brewing Science
Introduction and Water Quality
Water
Hydrogen Bonds
Water
Dissolved Ions in Water
• Enthalpy of Hydration
Mx+(g) + nH2O  Mx+(aq)
• As size of cation decreases or charge
increases, enthalpy increases (stronger
interactions)
Enthalpy of Hydration of Some
Typical Ions (kJ/mol)
Ion
H+
-Li+
Na+
K+
Rb+
Cs+
-Cr2+
Co2+
Zn2+
Hhyd
-1130
Ion
Al3+
Hhyd
-4665
Ion
Fe3+
Hhyd
-4430
-520
-406
-322
-297
-276
Be2+
Mg2+
Ca2+
Sr2+
Ba2+
-2494
-1921
-1577
-1443
-1305
FClBrIClO4-
-505
-363
-336
-295
-238
-1904
-1996
-2046
Mn2+
Ni2+
Cd2+
-1841
-2105
-1807
Fe2+
Cu2+
Hg2+
-1946
-2100
-1824
Hydrolysis of cations
• Metal ions in aqueous solution behave as
Lewis acids
• [M(H2O)n]x+ + H2O  [M(H2O)n-1(OH)](x-1)+ + H3O+
• Note the similarly to a typical acid ionization:
• HA + H2O  A- + H3O+
Analogous to a pKa
pH
pH = -log[H+]
K w  [H  ][OH- ]  110 14 M 2
 log[ H  ]  log[ OH- ]  14
pH  pOH  14
Acids
Ions in Brewing
Important Cations
• Calcium (Ca+2)
– Contributes to permanent water hardness
– Interacts with malt phosphates which lowers pH
during mashing and boiling
– Helps yeast flocculation and beer clarification
– Also aids protein coagulation during hot and cold
breaks
– According to Dave Miller the optimum is 50-100 mg/l.
Provided by Ken Woodson & the North Texas Home Brewers Association
Ions in Brewing
Important Cations
• Magnesium (Mg+2)
– Contributes to permanent water hardness
– Lowers mash pH similar to Calcium, but not as
effective
– Usually sufficient amount present in malt, so
seldom have to add to brewing water.
– Good yeast nutrient at 10-20 mg/l. However, at
30+ mg/l it can impart a sharp sour/bitter flavor
Provided by Ken Woodson & the North Texas Home Brewers Association
Ions in Brewing
Important Cations
• Sodium (Na+)
– Poisonous to yeast and harsh tasting when levels
are too high.
– Unpleasant harshness when combined with Sulfate
– Contributes sour salty taste at reasonable levels.
For brewing, should be below 50 mg/l
Provided by Ken Woodson & the North Texas Home Brewers Association
Ions in Brewing
Important Anions
• Bicarbonate (HCO3)– Neutralizes acids in dark malts
– Acts as a pH buffer
– Under 50 mg/l unless it is balanced by Calcium or
dark malts.
Provided by Ken Woodson & the North Texas Home Brewers Association
Ions in Brewing
Important Anions
• Sulfate (SO4)-2
– Accentuates hop bitterness and dryness at high
concentrations. It is strongly bitter above 500
mg/l
– For non highly hopped beers, levels should be
below 150 mg/l
– Creates an unpleasant harshness if combined with
Sodium
Provided by Ken Woodson & the North Texas Home Brewers Association
Ions in Brewing
Important Anions
• Chloride (Cl)– Enhances sweetness at low concentrations, but at
high levels it impairs yeast flocculation.
– Increases beer stability and improves clarity
– For light beers 1-100 mg/l is common; however,
it can be as high as 350 mg/l for beers with gravity
larger than 1.050
Provided by Ken Woodson & the North Texas Home Brewers Association
Water Analysis - pH
• pH, or potential hydrogen, is important in
brewing
– Enzymes that break down starches work best
over a pH range of 5.2 – 5.5
– If pH of sparging water is greater than 6.0, then
tannins can leak into wort causing harsh flavors.
– Rapid drop in pH during fermentation is common,
which inhibits bacterial activity
Provided by Ken Woodson & the North Texas Home Brewers Association
Water Analysis - Alkalinity
• Alkalinity is the amount of alkaline ions
present and is usually expressed as an
equivalent amount of CaCO3
• For water pH between 7 and 9, alkalinity is
basically the bicarbonate ion, expressed as an
equivalent amount of CaCO3
• Alkalinity, as equivalent CaCO3, should be less
than 50 mg/l for brewing pale beers
Provided by Ken Woodson & the North Texas Home Brewers Association
Water Analysis - Hardness
• Informally, water hardness was determined by
the amount of suds produced in soap, the harder
the water, the fewer the suds.
• Water hardness is measured as the amount of
Calcium (Ca+2 ) and Magnesium (Mg+2) dissolved
in water and is usually expressed as an equivalent
amount of CaCO3
Hardness = (100/40)* (mg/l of Calcium)
+ (100/24)* (mg/l of Magnesium)
Provided by Ken Woodson & the North Texas Home Brewers Association
Water Analysis - Hardness
Temporary Hardness
Calcium reacts with bicarbonate (HCO3)- ,
when heated, to precipitate Calcium
carbonate (CaCO3), which reduces the
amount of Calcium. The Calcium that can be
removed from the water through this boiling
process is called temporary hardness
Provided by Ken Woodson & the North Texas Home Brewers Association
Water Analysis - Hardness
Permanent Hardness
• Permanent hardness is the water hardness
that remains after boiling
• When alkalinity exceeds hardness, then the
water hardness is mostly temporary.
• Conversely, if the hardness exceeds the
alkalinity, the difference indicates permanent
sulfate hardness.
Provided by Ken Woodson & the North Texas Home Brewers Association
Water Adjustment for Extract Brewing
• Pre-treatment
– Odors/tastes: Chlorine, Iron, Sulfur, metallic, etc.
– Carbon Filters, Campden Tablets, Water Softeners,
Green Sand
• Flavor Tweaking
– Sulfate for hop bitterness
– Sodium/Chloride for Malt accentuation
• Fermentation Issues (Rare)
– Zn, Ca, Mn, Mg = Yeast Nutrition, Beer Haze
– 30 Years ago, malt extract was for baking
– Now, mineral levels for mash chemistry
fermentability have been done for you.
Provided by Ken Woodson & the North Texas Home Brewers Association
Brewing Water Treatment
Carbon Filtration
• Most municipal water supplies are treated
with chlorine to inhibit bacterial growth.
• Chlorine can interact with wort to produce
chlorophenols which can impart a plastic taste
to beer
• Chlorine should be removed from brewing
water. To remove chlorine you can use a
carbon filter
Provided by Ken Woodson & the North Texas Home Brewers Association
Brewing Water Treatment
Reverse Osmosis and Distillation
• RO removes about 94% of the ions from water.
If you use RO, then may need to add mineral
salts to increase the calcium level to an
appropriate level.
• Distillation removes all ions from water.
Complete distillation is not recommended
because it removes all yeast nutrients, however,
partial distillation may be appropriate
Provided by Ken Woodson & the North Texas Home Brewers Association
Brewing Water Treatment
Boiling
• Recall that calcium reacts with bicarbonate
(HCO3)- , when heated to a boil, to
precipitate calcium carbonate (CaCO3), which
reduces the amount of Calcium and the
amount of bicarbonate. The reduction in
bicarbonate will lower the pH of the water
• The process removes about 3 mg/l of calcium
for every 5 mg/l of bicarbonate removed
Provided by Ken Woodson & the North Texas Home Brewers Association
Mineral Salts
• Mineral salts are adding to brewing water to:
– Change the mash or sparge pH
• For pale malt mashes adding calcium sulfate will lower
mash pH. For dark malt mashes adding calcium
carbonate will increase mash pH
– Replicate the water profile of a famous brewing
region
– To achieve specific flavors in beer
Provided by Ken Woodson & the North Texas Home Brewers Association
Mineral Salts
• Common mineral salts added to brewing water
– Calcium Sulfate (Gypsum) CaSO4∙2H2O
• Ca 23.28%, SO4 55.79%, H2O 20.93%
• Increases water hardness and sulfate levels
– Magnesium Sulfate (Epsom Salts) MgSO4∙7H2O
• Mg 14%, SO4 55%, H2O 31%
• Increases water hardness and sulfate levels
– Calcium Carbonate (Chalk) CaCO3
• Ca 40.04%, CO3 59.96%
• Increases Calcium and strongly buffers mash pH
Provided by Ken Woodson & the North Texas Home Brewers Association
Mineral Salts
• Common mineral salts added to brewing water
– Calcium Chloride CaCl2∙2H2O
• Ca 27.26%, Cl2 48.23%, H2O 24.51%
• Adds Calcium and saltiness
– Sodium Chloride (Table Salt) NaCl
• Na 39.34%, Cl 60.66%
• Enhances bitterness and fullness of beer
Provided by Ken Woodson & the North Texas Home Brewers Association
Mineral Salts
Brewing Water Additions
• One gram of a mineral salt in one gallon of
water at 68o F will increase the total dissolved
solids by 264.2 mg/l.
• The 264.2 is the conversion from
grams per gallon to milligrams per liter.
Provided by Ken Woodson & the North Texas Home Brewers Association
Mineral Salts
Brewing Water Additions
• For example, If you add 1.5 grams of gypsum to
10 gallons of your brewing water, how much of
the Calcium ion have you added to the water?
Answer:
Mineral Salt ppm
(1.5g/10gallon)*(1gallon/3.785liters)(1000mg/1g)=39.63mg/l
Calcium ppm
(39.63mg/l*.2328 )= 9.22 mg/l of Calcium
Provided by Ken Woodson & the North Texas Home Brewers Association
Acidification
• The pH of brewing water can be reduced by
adding a small amount of food grade acid.
Typically, lactic, phosphoric, or sulfuric acid are
used.
• As a general guide, you can add small amounts of
food grade acid until the brewing water pH is
around 7. For modified pale malts that will not
undergo acid or protein rests, then you should
add food grade acid until the brewing water pH is
6.0
Provided by Ken Woodson & the North Texas Home Brewers Association
Acidification
• Acids can be used more precisely to lower
alkalinity, which will lower mash pH
• The amount of acid in milligrams/milliliter for
common acids used in brewing:
Lactic acid 85-90% w/w: 1,020 mg/ml
Phosphoric acid 85-88% w/w: 1,445 gm/ml
Sulfuric acid 95-98% w/w: 1,766 mg/ml
Provided by Ken Woodson & the North Texas Home Brewers Association
Acidification
• To calculate the milliliters of acid required to
lower alkalinity use the formula:
(Alkalinity Reduction in CaCO3 )*3.7854*gallons of water
milligrams of acid per milliliters
Provided by Ken Woodson & the North Texas Home Brewers Association
Acidification
• Example
If your brewing water has a pH of 7.9 and an
alkalinity of 89, how many ml of 85% lactic acid
should you add to 8 gallons of brewing water
to reduce the alkalinity to 50 mg/l?
Answer
lactic acid ml = (89-50)*3.7854*8 = 1.2 ml
1,020
Note that a teaspoon is 5 ml
Provided by Ken Woodson & the North Texas Home Brewers Association
Famous Brewing Waters
• The water at Burton upon Trent is very hard
and the sulfate levels are extremely high. The
high sulfate levels accentuate the bitterness in
English Bitters and Pale ales
• The water in London, Dublin and Munich is
high in bicarbonate which balances the dark
malts used to brew porters, stouts, and bocks,
in the respective regions
Provided by Ken Woodson & the North Texas Home Brewers Association
Famous Brewing Waters
• Plzen water is very soft with low
concentrations of dissolved ions.
• Decoction mashing is common in Plzen, in
part due to soft water. The decoction
process allows enzymes to work even though
the calcium levels are very low.
Provided by Ken Woodson & the North Texas Home Brewers Association
Famous Brewing Waters*
Mineral
Plzen
Calcium
7
Magnesiu
m
Sodium
Sulfate
Bicarbona
Chloride
te
2
2
5
15
5
Dortmund 225
40
60
120
180
60
Munich
75
18
2
10
150
2
Vienna
200
60
8
125
120
12
Burton
275
40
25
450
260
35
Dublin
120
5
12
55
125
20
Edinburgh
120
25
55
140
225
65
London
90
5
15
40
125
20
Plano
67
10
91
178
109
1
*Data from Greg Noonan's water workshop at the 1991 AHA Conference and
are in ppm (mg/l)
Provided by Ken Woodson & the North Texas Home Brewers Association