lecture

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lecture 1 and 2
beer and the brewing process
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alcohol -What is it? a class of molecules
that have an OH group methanol- 1
carbon ethanol- 2 carbons propanol- 3 carbons
butanol- 4 carbons pentanol- 5
carbons
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alcohol -Where does it come from?
fundamental metabolic processes extracting
energy from sugar
glucose
aerobic respiration - requires oxygen
- 36 ATP per glucose molecule - low
energy waste products, H2O and CO2
anaerobic respiration
alcoholic fermentation
lactic acid fermentation
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alcohol -Where does it come from?
anaerobic respiration fermentation -
extraction of energy from glucose without
oxygen - only 2 ATP per glucose molecule -
very inefficient, high energy waste
products - lactic acid - ethanol
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alcohol -Where does it come from?
Were only concerned with alcoholic
fermentation - many fungi and bacteria can
perform alcoholic fermentation fairly common
amongst microorganisms - Saccharomyces
cerevisiae brewers and bakers
yeast water sugar yeast time
alcoholic beverage - alcohol is a byproduct of
yeast metabolism, its a waste product, its
yeast poop
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alcoholic beverages
the source of sugar, the process, other
ingredients, and geographic origin are used to
classify types of alcoholic beverages In
other words, why are there so many types of
alcoholic beverages? What makes beer beer?
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alcoholic beverages -Sugar source
beer wine sake mead cider pulque masato chi
cha cyser birch beer
grains
whiskey, vodka, gin
brandy, grappa
grapes, fruit
awamori
rice
honey
distilled mead
apples
calvados, apple jack
agave sap
tequila
manioc root
??
corn
bourbon
honey and apples
birch sap
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alcoholic beverages -Process
beer wine sake mead cider pulque masato chi
cha cyser birch beer
grains
whiskey, vodka, gin
brandy, grappa
grapes, fruit
awamori
rice
honey
distilled mead
apples
calvados
agave sap
tequila
manioc root
??
corn
bourbon
honey and apples
birch sap
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alcoholic beverages -Process
the process - wines typically have nothing
added to them, just juice not cooked, but
cider too - sake is made with different
yeasts than beer, different process - chicha
is made with different yeasts than beer,
different process
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alcoholic beverages -History
geographical factors - where each type of
sugar source was first domesticated -
degree of isolation - local names/traditions
lead to divergence of beverages
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alcoholic beverages
today, beer is usually made with four primary
ingredients (1) water (2) malted
barley (3) hops (4) yeast Modern beer
also has a very particular process of
production the beer we know today has only been
around since the mid 1600s
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brewing beer
cultivate malt mill mash sparge boil hop fine cool
oxygenate pitch ferment age fine filter package e
njoy
HISTORICAL DISCLAIMER
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brewing beer -Cultivating
What are grains? - Angiosperm, grasses,
Poaceae, (flowering plants) - the fruit of
the grass, but starchy not sugary - Hordeum
vulgare, barley
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brewing beer -Cultivating
other grains used in brewing - wheat -
corn - rice - rye - oats
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brewing beer -Malting
but yeast cant use starch to live, thus they
cant make alcohol from starch - this is not
an issue in wine making, why? - a big
difference in process
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brewing beer -Malting
what is starch?
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brewing beer -Malting
need to convert the starch to sugar so that the
yeast can use the energy stored in the starch to
make alcohol - what is fruit for? why do
plants have fruit? why do grasses have grains?
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brewing beer -Malting
no living thing (or very few living things) can
use starch directly to get energy - most
living things need to convert starch to sugar
first - yeast cant do it - some fungus can
- plants can - humans can
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brewing beer -Malting
brewers borrow the plants ability to convert
starch to sugar by tricking them into thinking
theyre growing this is malting
a-amylase ß-amylase
also in human saliva
soak sprout spread and germinate kiln
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brewing beer -Malting
malting is also where much of a beers character
is determined - type of barley used - 2 row
vs 6 row - color, protein - American -
Canadian - English -Maris Otter - Scottish
Golden Promise terroir? - German -
Belgian - malting method - floor malted -
machine malted - kilning fuel peat, wood smoke
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brewing beer -Malting
kilning - temperature - length - moisture
content types of malt - base malt -
biscuit - Vienna - Munich - aromatic -
crystal - chocolate - black patent - roasted
barley
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brewing beer -Milling
need to expose the starch dont want to
pulverize the grains, need to keep the husks
intact for the sparge or else big trouble
peated malt
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brewing beer -Mashing
converting starch to sugar by activating a suite
of enzymes that were created by malting the
grain mix milled grains with water in a mash
tun water/grain ratio, temperature, water
chemistry all affect how the starch is converted
low temps, 140F lots of glucose high
temps, 160F lots of complex sugars, dextrins
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brewing beer -Mashing
glucose
140F
150F

starch
160F
glucose
maltose
dextrin
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brewing beer -Mashing
some beers use unmalted grains in the mash such
as corn, rice wheat, the big 3 use a lot of these
adjuncts - how could this be a problem? how to
remedy the problem?
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brewing beer -Sparging
how to separate the crushed grain from the sweet
liquid, the wort, that will become beer? -
straws - grain bed, husks
lauter tun (usually mash tun too)
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brewing beer -Sparging
recirculation recirculate the wort until it is
clear parti gyle do one mash, then drain all
the wort off, add more hot water, do
another mash, drain all the wort,
continue until all sugars are gone - usually
results in two or three smaller batches of
beer that range from strong to medium to
weak sparging do one mash, begin to drain the
wort off and as the wort level falls, add
hot water, sparge water, to rinse the sugars
from the grains, continue until all sugars
are rinsed - usually get one big batch of beer
that is one strength, weaker than first
runnings of parti gyle but stronger than
second runnings
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brewing beer -Sparging
What do I mean by strong and weak
wort? original gravity the density of the wort
before fermentation determined by how
much sugar is dissolved in the
wort high gravity lots of sugar high
density lots of sugar potential for lots of
alcohol
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brewing beer -Boiling
wort the clear, sugary liquid that is collected
during run off, also called sweet
wort collected in the boil kettle or just kettle
why boil? - sterilize wort - coagulate
proteins - concentrate sugars - extract hop
oils
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brewing beer -Hopping
Humulus lupulus a tall, non-woody vine that
dies back to the ground every winter, perennial,
Cannabaceae family, sister genus to hemp female
flowers produce cones that bear lupulin glands
which contain many different oils that
contribute bitterness, flavor, and aroma to beer,
also bacteriostatic, used to balance sweetness
of malt must be boiled vigorously to extract
the oils
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brewing beer -Hopping
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brewing beer -Hopping
many different varieties, typically grouped by
region of origin, American hops most distinct
- England - Fuggles - East Kent
Goldings - Target - Challenger -
Germany - Spalt - Tettnanger -
Hallertau
- United States - Cascade - Simcoe -
Chinook - Magnum - Czech Republic -
Saaz
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brewing beer -Hopping
hops are just one type of spice others still
used today - orange peel - coriander more
historical - rosemary - spruce tips - myrica
gale - wormwood - mints
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brewing beer -Fining
fining the addition of material to beer or wort
that aids in the clarification of the wort and
beer during the boil, carrageen in Irish Moss
helps pull proteins out of solution
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brewing beer -Cooling
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brewing beer -Oxygenating
even though fermentation is an anaerobic process,
we want the yeast population to be large enough
and strong enough to have a healthy fermentation
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brewing beer -Pitching
pitching the addition of yeast to the cooled
wort, also called bitter wort now until very
recently, 1940s and 50s in England,
mixed cultures of yeast were pitched pure
culture fermentation, only one type of yeast,
was not adopted until 1890s in Europe, now
almost universal
1/1000 of a millimeter
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brewing beer -Yeast and fermentation
fungi
Ascomycota
yeast
Basidiomycota
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brewing beer -Yeast and fermentation
Basidomycota
Ascomycota
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brewing beer -Yeast and fermentation
fermentation the period of time from pitching to
complete attenuation (also the biochemical
process that makes ATP without
oxygen) attenuation the degree to which the
yeast convert sugar to alcohol and
CO2 original gravity density of the bitter
wort before pitching, many sugars
dissolved in the wort final gravity
density of beer after fermentation is
complete, depends on yeast strain, mash
temps
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brewing beer -Yeast and fermentation
stages of fermentation primary fermentation
-where vast majority of attenuation occurs,
3-20 days lag phase yeast are acclimating
to wort, little obvious activity, 2-24
hours aerobic phase -yeast grow very
rapidly, population increases
exponentially, consumes much of the sugar,
much attenuation occurs here, consumes
oxygen, obvious activity, 1-5
days anaerobic phase yeast begin to ferment
the sugars left in the wort, activity
slows, 1-15 days
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brewing beer -Yeast and fermentation
secondary fermentation to be covered in aging
section
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brewing beer -Yeast and fermentation
Saccharomyces cerevisiae sacchar- sugar
(saccharide, saccharine) myces- fungus
(ancient Greek) ceres- Greek goddess of
agriculture? (cereal) Saccharomyces
carlbergensis Carlsberg- Danish city where
lager species was first isolated
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brewing beer -Yeast and fermentation
Saccharomyces cerevisiae -ale yeast warm
fermentation, between 65-90F (avg 70F),
typically more character than lager
strains, less attenuative, short
fermentation and aging, as short as 5 days
from grain to glass, top fermentation
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brewing beer -Yeast and fermentation
S. uvarum (S. carlbergensis) lager yeast cool
fermentation, between 48-55F, typically
cleaner than ale strains, more
attenuative, long fermentation and aging,
primary 20 days, secondary or lagering
period, at least 14 days, bottom
fermentation
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brewing beer -Yeast and fermentation
many different strains within each species, 1000s
of strains - in addition to alcohol and CO2,
different strains contribute different
flavors and aroma - Belgian strains lots of
character, fruity, clove, can be very
attenuative even though theyre ale
strains - English strains lots of character,
fruity, bready, not attenuative, ale
strains - German strains mostly lager
strains, clean, attenuative - American
strains both ales and lager, typically
clean
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brewing beer -Yeast and fermentation
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brewing beer -Yeast and fermentation
spontaneous fermentation no yeast is added by
hand Belgian lambic style beer many
different microorganisms
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brewing beer -Aging
after fermentation, beer is generally racked from
one vessel to another, from the primary
fermenters to the aging tanks beer is aged for a
couple reasons - to complete attenuation -
for proper flavor development, yeast reabsorb
certain molecules, chemical reactions occur
etc. - for the beer to clear aging also
known as secondary fermentation some ales not
aged at all, Upland Wheat, most aged only 1-2
weeks, very strong ales aged up to a year or
more
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brewing beer -Aging
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brewing beer -Aging
lagering a long period of cold aging that is
normally required when using a lager strain,
lager to store lagering takes at least 2
weeks, usually a month to 6 weeks, the
stronger the beer, the longer the aging
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brewing beer -Fining
at this stage, finings are added to encourage the
yeast to drop out of suspension, but also
proteins and other large, haze forming molecules,
both a physical and electrical process isinglass
and gelatin are popular finings, some strict
vegetarians object to its use, swim bladders and
bones etc. usually used in British
breweries, synthetics are becoming more and
more popular such as polyclar and DE
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brewing beer -Filtering
beer is typically filtered immediately before
packaging filtering removes all yeast and other
microorganisms, can also remove proteins and
other large molecules has an effect on
packaging because filtering impacts stability of
the product, when stripped of large molecules,
there cant be much chemical activity in
the beer and thus it cant change much and of
course with everything living having been
stripped out, nothing can grow and spoil the
beer that way
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brewing beer -Packaging
cans bottles kegs casks How to get the gas into
the beer? artificial carbonation filter the
beer and forcibly inject CO2 then
package natural carbonation - do not
filter, add extra sugar or actively
fermenting wort, and put a cap on it - filter,
add some sugar AND yeast or actively
fermenting wort (Sierra Nevada)
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brewing beer -enjoy responsibly