Brewing

1
Brewing

• Lindsay Korth
• Jacob Spizziri
• Edward Schoenherr
• Brenna Priest

2
What is brewing?

• Brewing is the production of alcoholic beverages
  and alcohol fuel through chemical mixing
  processes of infusion, boiling and fermentation.
  
• The term is generally used to describe beer
  production, however the fermentation processes
  are also used in the production of wine, mead,
  sake, and soy sauce

3
Why brewing?

• Because everybody loves beer!
• Beer is the largest alcohol segment nationwide,
  accounting for roughly 85 of all alcohol volume
  sold in the United States

4
History

• The first archeological evidence of beer
  production comes from 6000 BC in ancient Babylon
  
• Earliest known chemical evidence comes from
  organic residue from inside a pottery vessel
  dated 3500-3100 B.C. from the site of Godin Tepe
  in the Zagros Mountains of western Iran
• Other records are shown in Ancient Egyptian
  hieroglyphics and Sumerian writings
• Beer was known to Germanic and Celtic tribes in
  Europe as far back as 3000 BC
• Its possible that beer-like beverages were
  independently developed throughout the world soon
  after a tribe or culture had domesticated cereal
• Basis of beer came from loaves of specially made
  bread
• Beer loaves made from richly yeasted dough,
  possibly with the addition of malt
• Lightly baked, then resulting bread was crumbled
  and strained with water
• Dates, extra yeast added, dissolved mixture was
  fermented in large vats

5
Modern Studies

• Louis Pasteur, father of microbiology first to
  study beer production 1850s
• Discovered that all fermented materials contained
  yeast
• Spoiled batches of beer occurred from bacterial
  contamination of the ferment, contamination could
  be prevented by heating wort to 55 degrees C
  before adding yeast
• Pasteurization still used today
• U.S. beer industry got its start in the 1840s and
  1850s

6
Sources

• http//www.chemheritage.org/EducationalServices/ph
  arm/antibiot/readings/ferment.htm
• http//www.scq.ubc.ca/the-unacknowledged-workers-o
  f-the-biotechnology-industry-microbes/
• http//www.beer-brewing.com/beer-brewing/US_beer_i
  ndustry/beer_industry_history.htm
• http//en.wikipedia.org/wiki/History_of_beer
• http//www.museum.upenn.edu/new/research/Exp_Rese_
  Disc/masca/beer.shtml
• http//www.beer-brewing.com/beer-brewing/mashing/c
  hemical_changes_mashing.htm

7
Whats to come..

• 7 stages of the brewing process
• Mashing
• Wort separation
• Boiling
• Fermenting
• Conditioning
• Filtering
• Packaging

8
Mashing

• Conducted over a period of time at various
  temperatures in order to activate the enzymes
  responsible for the acidulation of the mash
  (traditionally for lagers) and the reduction in
  proteins and carbohydrates
• malt and adjunct particles swell, starches
  gelatinize, soluble materials dissolve, and
  enzymes actively convert the starches to
  fermentable sugars
• end result is wort with a fixed gravity (OG), a
  set ratio of fermentable and non-fermentable
  sugars, and proteins (soluble and non soluble)
  that affect physical and biochemical changes
  during fermentation

9
Chemical changes

• Acidification
• responsible for reducing the initial mash pH for
  traditional decoction mashing of lager beers
• Protein Degradation
• Protease enzymes comprise the group of enzymes
  that reduce high-molecular-weight proteins to
  simpler amino-acid constituents by breaking the
  peptide bonds between proteins
• Proteinase
• responsible for degrading albumins already
  dissolved in the wort, along with insoluble
  globulins, into simpler medium-sized protein
• Peptidase
• responsible for degrading medium-sized proteins
  (peptones and polypeptides) into smaller proteins
  (peptides and amino acids).

10
Chemical Changes cont.

• Starch degradation
• conversion of starch molecules into fermentable
  sugars and unfermentable dextrins
• Principle enzymes responsible for starch
  conversion
• 1. Alpha-amylase- very rapidly reduces insoluble
  and soluble starch by splitting complex starch
  molecules into many shorter chains that can be
  attacked by beta-amylase.
• 2. Beta-amylase- more selective than
  alpha-amylase since it breaks off two sugars at a
  time from the starch chain.

11
WORT SEPARATION
(wort boiler)
12
Wort Separation

• The Separation of the wort (liquid extract) from
  the solid materials (found in the mash).
• Undissolved solid materials include large
  amounts of protein, poorly modified starch, fatty
  material, silicates, and tannins
• Objectives of wort separation
• Produce clear wort
• Obtain good extract recovery
• Operate within the acceptable cycle time

13
Wort Separation

• Three different methods
• Lauter Tun
• Mash Tun or Filter
• Strainmaster
• Two stages of separation processes
• Wort run-off
• Extract is separated in an undiluted state from
  the spent grains.
• Sparging
• Extract remains with the grains and then rinsed
  off with hot water.

14
Lauter Tun

• Most widely-used wort separation vessel system in
  North America and Europe.
• Tank with small holes in the bottom to hold back
  the large bits of grist and hulls.
• The bed of grist (that settles on the bottom) is
  the actual filter.

15
Mash Filter

• Sometimes preferred by large-volume brewers.
• Plate-and-frame filter.
• Empty frame, containing the mash, has capacity of
  approx. one hectoliter (100 L).
• The plate contains the support structure for the
  filter cloth.
• Arranged as frame, cloth, plate, cloth, and
  plates at end of each structure.
• Cycle
• Mash filter is flushed, then preheated with hot
  water.
• Mash is pumped from mash mixer into the filter
  through the top channel, completely filling the
  filter frames.
• Process takes about 20 to 30 minutes.

16
Strainmaster

• Most rarely used.
• Patented by Anheuser Busch.
• Separates wort by allowing it to flow into
  horizontal slotted tubes.
• Filtration is carried out by the spent grain.
• Recirculation continues until desired wort
  brightness is achieved.
• Wort is then run to the kettle.

17
Boiling

• Following Wort Separation, clear wort must be
  conditioned by boiling in the kettle.
• Stabilizes the wort and extracts the desirable
  components from the hops.
• Ensures sterility preventing infections.
• Biochemical changes occur during boiling
• Kettle Additives
• Wort Boiling Systems

(Boiling Wort Hop Pellets Cause the Greenish
Tint)
18
Biochemical Changes

• Sterilization
• Wort entering the kettle contains microorganisms
  which can result in off-flavors and other
  problems.
• Yeast, molds, bacteria.
• Enzyme Inactivation
• Fixes the carbohydrate composition of the wort.
• Inactivating residual enzymes responsible for
  carb and protein degradation that may have
  survived mass-off.

19
Biochemical Changes

• Protein Precipitation
• Occurs as the wort loses its turbidity during
  boiling, material breaks out of suspension and
  precipitates as proteins coagulate.
• Necessary to decrease level of high molecular
  weight nitrogen in malt.
• Isomerization
• Major flavor contribution of hops in beer is
  bitterness from iso-alpha acids.
• Insoluble alpha acid extracted from hops is
  converted to a more soluble iso-alpha acid.

20
Biochemical Changes

• Color Development
• Color of the wort becomes darker during boiling,
  caused by
• Production of Melnoidins
• Occurs when reducing sugars from carbs react with
  amino acids derived from proteins during mashing.
• Oxidation of Polyphenols
• Additional source of color formation derived from
  malt husks and hops.
• Known as tannins.
• Carmelization of Sugars
• Chemical process that affects sugars subjected to
  200C .

21
Biochemical Changes

• Dissipation of Volatile Constituents
• Boiling drives off volatile wort compounds
• Dimethyl, Sulfide, Aldehydes, and Hydrocarbon
  components of the hop oils.
• Concentration of Wort
• Concentrated by evaporation because water used in
  mashing produces wort lower in specific gravity
  than the target gravity.
• Reduction in Wort pH
• pH of the Wort decreases during mashing and
  boiling to reach a final pH between 5.2 and 5.3.

22
Kettle Additives

• Hops
• Timing
• Metered out in portions throughout
• the boil.
• Finish Hopping
• For hop flavor and aroma in beer hops are added
  very late in boil.
• Rates
• Determined by alpha-acid content, desired hop
  flavor and aroma, condition of hops, efficiency
  of hop extraction, brewing process, type of
  brewing water.

23
Kettle Additives

• Copper Finings
• Form of seaweed consisting of K-carrageenan
  (complex starchy polymer similar to polyphenols).
• Has negative charge and is effective in
  precipitating positively-charged proteins from
  wort solution.
• Dosage Rate
• Ranges from 10 to 80 mg/L.
• Differs due to variations in grist formulations,
  mashing systems, specific gravities of the wort.
• Choice of Material
• Range of physical forms and degrees of
  purification of copper fining products
• Powders, tablets, granules, refined carrageenan,
  alkali-washed seaweed.

24
Kettle Additives

• Acids
• Tannic Acid
• Reduces hop-bittering utilization.
• Reduces color reactions.
• Improves wort clarity through enhancement of hot
  break formation.
• Lactic Acid
• Lowers pH of the wort.
• Produced in propagation tanks.

25
Kettle Additives

• Calcium Sulfate or Calcium Chloride
• Lowers pH of wort during boiling by 0.10.2
  units.
• Syrups and Sugars
• Dry or liquid form
• wort extenders
• Increases extract without added investment in
  brewhouse vessels.
• Flavorings
• Fruits, spices, herbs.
• During or after boil.

26
Wort Boiling Systems

• Direct-Fired Kettles
• Made by copper
• Inefficient
• Improperly transfers heat into the wort
• Scorches the wort
• Restricted by volume of wort that can be boiled
  at once
• Kettles with External Heating Jackets
• Very common
• Symmetrically arranged around the vessel OR
• Jackets may be placed asymmetrically for rolling
  boiling.

27
Wort Boiling Systems

• Kettles with Internal Heating Systems
• Allows for more efficient heat transfer and
  larger kettles for boiling larger volumes of
  wort.
• Heaters are located in center of kettle for
  turbulent boil.
• Wort is heated by flowing upwards through heating
  unit into a venturi tube.
• Emerges above level of the wort striking a
  deflector plate.
• Kettles with External Wort Boilers
• Boiler is outside of kettle (called calandria)
  through which wort is pumped.
• Most common is tube and shell heat exchanger.
• Provides large surface area for vapor bubbles to
  nucleate.
• Provides excellent volitization.

28
Sources

• The Brewer's Handbook, (2008). Apex Publishers.
  Retrieved March 4, 2009, from The Brewer's
  Handbook Web site http//www.beer-brewing.com/bee
  r-brewing/beer_chapters/
• Brewing. (2/24/2009). In Wikipedia Web.
  Retrieved 3/1/09, from http//en.wikipedia.org/wik
  i/Brewing
• (2008). Brewing Beer. Retrieved March 4, 2009,
  from www.cubby-hole.com Web site
  http//www.cubby-hole.com/Brewing20Beer20Making
  20the20Wort.htm

29
Fermentation

• Fermentation is the process by which enzymes
  produced by yeasts convert the glucose in the
  wort into carbon dioxide and ethyl alcohol
• Giving beer both its alcohol content and
  carbonation
• To start the process the wort is cooled and sent
  to the fermentation tank
• Depending on what type of beer is being brewed
  and what type of yeast is being used the
  temperature must be kept at a certain temperature
  during this process
• Ale 20C(68F)
• Lager 9C(48F)
• Once in the fermentation tank the brewer selects
  and adds a type of yeast. Depending upon which
  type is selected a different fermentation process
  will be used and a different beverage will
  result.
• The fermentation process typically takes from
  10-20 days.

30
Fermentation (cont.)

• There are three types of fermentation Top,
  Bottom, and Spontaneous Fermentation
• Fermentation is broken up into three stages
• Lagtime
• Primary
• Secondary.

31
Yeast

• Certain yeasts can only breakdown sugars up to a
  certain percentage of alcohol. Beer yeasts
  about 5, Wine about 12
• The yeast its self goes through two processes
  Aerobic and Anaerobic
• The reaction of yeast with the wort produces a
  variety of flavor compounds which are crucial to
  the taste of beer
• acetaldehyde (green apple aroma)
• diacetyl (taste or aroma of buttery,
  butterscotch)
• dimethyl sulfide (DMS) (taste or aroma of sweet
  corn, cooked vegetables)
• clove (spicy character reminiscent of cloves)
• fruity / estery (flavour and aroma of bananas,
  strawberries, apples, or other fruit)
• C6H12O6 --------------gt 2C2H5OH 2CO2

32
Yeast (cont.)
33
Aerobic

• During this part of the process the wort is
  exposed to oxygen
• This is the initial rapid process in which the
  yeast doubles its colony size every four hours

34
Anaerobic

• During this process there is no oxygen present in
  the mixture
• As a result of a lack of oxygen the yeast focuses
  on converting sugar to alcohol rather that
  increasing the number of yeast cells

35
Top Fermentation

• Top fermentation occurs at higher temperatures
  (15-25C)
• This causes a faster fermentation period
• The result is beers with a more fruity and
  aromatic
• The quantity of yeast used is less than is used
  in bottom fermentation
• The yeast stays at the surface throughout the
  fermentation process
• These beers are typically darker
• Porter
• Stout
• Ale

36
Bottom Fermentation

• Beers made with Bottom Fermentation are the most
  widespread
• Pale beers
• Blonde beers
• Low alcohol concentration
• Neutral taste
• Yeasts are typically added at lower temperatures
  (6.5-8.5C)
• Once the fermentation is complete the temperature
  of the of the beer is lowered to 0 degrees
  Celsius.
• At this temperature the yeasts settle down to the
  bottom of the fermentation tank and the beer is
  siphoned off

37
Spontaneous Fermentation

• Typically used in certain Belgian specialty beers
• In this process the beer is fermented again in
  rooms at the temperature of 16C without adding
  any yeast
• Only microorganisms floating in the air touch the
  beer during this natural fermentation

38
Lag Phase

• The lag Phase is the time period that refers to
  3-15 hours after the yeast is added to the wort
• Yeast begins the process of acclimating to its
  environment and absorbing oxygen
• During this process is when the yeast reproduce,
  providing a sufficient amount of yeast cells to
  complete fermentation

39
Exponential Growth Phase

• This phase refers to a 1-4 day time period after
  the yeast begins to come out of the lag phase
• At this point the yeast begins to consume the
  sugars present in the wort
• CO2 begins to be produced leaving a layer of foam
  on the surface of the wort
• During this phase yeast cells will be reproduced
  rapidly and ethyl alcohol and flavor compounds
  will be produced

40
Exponential Growth (cont.)

• Sugars in the wort are consumed in a certain
  order
• Glucose, is consumed first in that it is the
  simplest of the sugars.
• Makes up aprox. 14
• Maltose
• Makes up aprox. 59 of wort sugars
• Gives beer its characteristic flavors
• Maltotriose
• The most complex sugar, aprox. 27
• Fermentation typically stops at this point
• Many yeasts are unable to ferment this sugar

41
Stationary or Conditioning Phase

• 3-10 days on the tail end of fermentation
• At this point yeast grown slows down
• When beer enters this stage it is referred to as
  green beer because the balance of flavor in the
  beer is not acceptable
• During this period the beer matures
• Yeast reabsorbs the diacytyl produced during
  fermentation
• Hydrogen Sulfide gas leaves the beer
• The beer is then siphoned or pumped into another
  holding tank leaving the yeast and other solids
  behind
• After this process is complete the beer is cooled
  slowly

42
Filtering

• Filtering is a process that further stabilizes
  the flavor of the beer
• Not all beers are filtered
• Several different methods of filtration
• Diatomaceous earth
• Naturally occurring chalk-like porous rock
• Cloth filters

43
Beer filtration process

• The filtration process stabilizes the beers
  flavor, and gives it a desirable appearance.
• Filtering starts by removing unwanted matter from
  beer such as, hops, grain and yeast particles.
• the two most common forms of filtration are the
  use of screens or kieselguhr (a chalk-like rock
  crumbled into fine powder)
• Not all beer is filtered. Some brewers do not
  filter their beer to add flavor and body to their
  product.

44
Screening

• Screens come in a variety of porosity levels.
  Brewers choose different levels of porosity
  depending on how clear they want their beer.
• Screens are often layered to trap bigger
  particles first, and then collect smaller
  particles as the beer moves thru the filter.
• Screen filters are easy to use, but require
  frequent cleaning.

45
kieselguhr

• Kieselguhr is a fine chalk like powder, that is
  naturally porous and abrasive.
• Beer is pored thru a layer of this powder as it
  acts as a filter media.
• Kieselguhr is a much more complicated process of
  filtration, but can filter higher quantities of
  beer and does not require as frequent cleaning.

46
Filtration ratings

• the three normally used filtration ratings for
  brewing are rough, fine and sterile.
• Rough filtration leaves some cloudiness in the
  beer, but is noticeably clearer than unfiltered
  beer.
• Fine filtration eliminates all cloudiness from
  the beer, giving it a clear appearance.
• Sterile is as the name implies, and removes
  almost all microorganisms from the beer.

47
Packaging

• The finished beer product is then packaged and
  consumed
• Bottles
• Kegs, metal or wooden
• Cans

48

• http//www.whitelabs.com/beer/Yeast_Life_Cycle.pdf
  
• http//beeradvocate.com/beer/101/yeast.php

• http//www.whitelabs.com/beer/Yeast_Life_Cycle.pdf
  
• http//beeradvocate.com/beer/101/yeast.php
• http//spot.colorado.edu/kompala/lab2.html