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Beer
MGMT 252 – Wine Industry
Fenix Theuerkorn – VIU
Introduction
• As we have learned yeast is responsible
for the fermentation of wine from the
conversion of sugar into alcohol
• Bread, beer, and wine are the main food
products associated with yeast
fermentations
• Saccharyomyces cerevisiae is the most
common yeast species for these purposes
Bread
• Ancient societies used grains to produce
porridges, gruels, and unleavened bread
• As societies became more sophisticated,
leavened breads became more popular
• In early times, bakeries were often
attached to breweries so that the yeast
by-product of brewing (S. cerevisiae)
could be used for bread-making
• S. cerevisiae is commonly called “baker’s
yeast”
Beer
Essential Ingredients
•
•
•
•
hops for flavor and antimicrobial activity
yeast to produce alcohol and CO2
water
malted barley to provide fermentable
carbohydrate
hops
Beer
• German purity laws forbid the use of any
other ingredients (1516)
• Different hops give different beers their
distinctive flavors
• Other countries (including U.S.) allow less
expensive cereals, grains, or corn to be
used to replace malt as the carbohydrate
Beer-making
• Process consists of malting, mashing,
wort boiling, fermentation, and postfermentation treatments
• Yeast cannot ferment starch in the barley,
so it is malted and mashed
• Sweetness in beer comes from the malted
barley
Malting
• Grain is steeped in water for 24 – 48 hrs
to induce germination
• This breaks down the cell wall and protein
matrix that contains the starch granules
and liberates amylases
Mashing and Wort
Boiling
• Amylases break the starch into
fermentable carbohydrates
• After mashing, the liquid malt is almost
ready to ferment
• Herbs, usually hops, are added for flavor
and antimicrobial activity
• The mixture of hops and liquid malt is
boiled and then cooled to ~20oC
Fermentation
ALES
• S. cerevisiae grows on top of the
fermentation mix and is used for ales
LAGERS
• S. carlsbergensis settles to the bottom
and is used for lagers
• Cooler fermentation
Fermentation
Fermentation
• The yeast from one fermentation is used
to inoculate the next batch for 10 – 15
fermentations and then, a new inoculum is
reintroduced
• The yeast uses the various sugars in the
wort sequentially, with simple sugars
being fermented first and maltotriose
relatively later (except for some ales)
Fermentation
• Ethanol production continues after the
yeast stops growing
• Flavor compounds, such as aldehydes
and higher alcohols, are produced
Post-fermentation
• Includes “aging” to remove the “green”
flavors caused by diacetyl and
acetaldehyde
• These can impact the taste adversely as
humans can taste them at very low
concentrations
• Aging in casks, storage in the presence of
yeast at 15oC, and avoiding O2 exposure
helps to remove flavor defects
Post-fermentation
• Most beers are filtered until clear,
although cloudiness of “boutique” beers is
part of their charm
• Cellulose fiber or pumice are used as filter
aids to enhance removal of the yeast by
filtration
Process: Brewing Beer
Beer Character
Color
 Color is from the type of grains and roasting level. Colors
range from straw to black and most of the earth tones.
Bitterness
 Bitterness is from the addition of hops during the boiling
process. Bitterness levels are controlled by the amount
and varieties of hops.
Gravity
 The term “gravity” refers to the density of beer which is
determined by the amount of soluble sugars in the beer. In
North American this is usually measured as brix. The
primary soluble sugar in beer is derived from the malted
grain, which is called maltose.
Major Beer Styles
Ale
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•
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Ales
Lambic
Stout
Wheat Beer
Lagers
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Lagers
Pilsner
Bock
Märzen
Exceptions:
Beer using both ale & lager fermentation
Steam beer
 Altbier
 Kölsch

Influence of beer
Karl Marx claimed communist revolution
could not happen in Köln (Cologne)…
… workers drink with their bosses.