Transcript Alcoholic Beverages

Alcoholic beverages
David S. Seigler
Department of Plant Biology
University of Illinois
Urbana, Illinois 61801 USA
[email protected]
http://www.life.illinois.edu/seigler
Alcoholic beverages from plants - Outline
Importance
o Historical - origins
o Nutritional
o Abuse
Wines
o Botanical - grapes
o Process
Beers
o Botanical - cereal grains
o Process
Distilled beverages
o Brandies etc.
o Whiskeys
Reading
• CHAPTER 14 IN THE TEXT, 332 ff.
Introduction
• All alcoholic beverages involve the action of
fungi.
• Most involve the genus Saccharomyces.
These yeasts covert six carbon sugars such
as glucose to ethanol and carbon dioxide and
live under anaerobic conditions. Yeasts can
tolerate fairly high concentrations of alcohol
(up to about 14-18%) in the medium.
• Alcoholic beverages are known from virtually
all cultures. These beverages are major
social problems, but also sources of nutrition.
• Many plants have been used to prepare
alcoholic beverages. Mead is made from
fermented honey.
• Plants often store nutrition as starch. Yeasts
cannot use starch. The starch is broken down
by enzymes in the plant into sugars. The
sugars are then converted by the yeasts into
ethanol and carbon dioxide.
• Alcohol is a lipid and moves freely across
membranes in the stomach.
• Alcohol is broken down in humans, but also
affects the neurons and is a non-selective
central nervous system depressant.
Wines
• Wine is fermented fruit juice. The most
important fruit is Vitis vinifera
(Vitaceae), but any fruit can be used.
• Yeasts occur on the skins of most fruits
and if the fruits are mashed, the sugarcontaining juices begin to ferment.
Yeast on the outside of grapes
B. Lehane, Power of Plants, McGraw Hill.
New York. 1977
• Winemaking probably began as one of the
earliest of human enterprises (8000-3000
B.C.).
• The wine grape was domesticated by at least
4000 B.C. Wine was used for Egyptian
worship ceremonies.
• Wine only became a popular beverage about
2000-1000 B.C. in Greece.
• About 600 B.C., wine growing reached
France.
Grape motif in an
Egyptian tomb
B. Lehane, Power of Plants, McGraw Hill.
New York. 1977
• Wine grapes were introduced early into the United
States.
• The Spanish introduced grapes into California in
the 1700's.
• Between 1850 and 1860, the root louse,
Phylloxera, was introduced inadvertently from
North America into Europe. This insect decimated
fields of Vitis vinifera. The problem was solved by
making hybrids or grafting European grapes on
American grape roots.
Grape flowers and fruits, Vitis vinifera, Vitaceae
Vineyards near
Lausanne,
Switzerland
• Many good quality wines are still made in the
same way they have been made for
centuries. However, most wines are now
made by sophisticated highly controlled
processes.
• Grapes are crushed (still by foot or with crude
presses in many parts of the world).
• The juice is then often treated with sulfur
dioxide to kill native yeasts.
• See diagram p. 343.
Newer style equipment for pressing grapes
Grape pomace after pressing
• If white wine is to be made, the juice is put
into fermentation tanks and the peels and
stems re-pressed.
• If red wine is to be made, the skins are
added.
• Special strains of yeasts are added to the
liquid from the grapes. These are often highly
guarded trade secrets and proprietary
substances.
• After 8-10 days, the liquid is drawn off and
allowed to ferment for another 20 days to one
month. Sediment forms.
Wine fermentation tanks
• At this point the wine is drawn off and
placed in aging tanks. White wines are
usually aged from 1 year to 18 months
and red wines as long as 5 years.
Stainless steel aging tanks for wine
Aging of wine in barrels
• White wines are generally not too good
after 5 years; red wines improve up to
30-40 years.
• Wine labelling: see p. 486.
• Champagne and sparkling wines are
made by putting the wine into a bottle
with a little added sugar. The carbon
dioxide produced carbonates the wine.
The sediment is removed and the the
wine maintained under pressure.
Aging of champagne in a New York winery
• Apples and pears are used to make
cider and perry respectively.
• To make fortified wines, ethanol or
distilled beverages such as cognac are
added.
• One group (including port, sherry, and
madeira) is made exclusively from
grapes, whereas the second group
includes aperitif wines and other
flavorings (such as Dubonnet and
vermouth).
• As many as 40 million metric tons of grapes
are produced per year.
• The major wine making countries are the
former USSR, France, Italy, USA, Spain,
Germany, Australia, Argentina, Chile and
South Africa.
• Consumption of wine in France is about 30
gal per person per year and about 2 in the
U.S.
Beer, ale and stout
• Beer making goes back at least 6000
years. The Sumerians had records
about brewing of beer.
• Early brewing is intimately linked with
bread making. This is one way of
making the grains more edible.
• Although the Egyptians used wine for
religious ceremonies, they commonly
drank beer.
Barley fields in California
and Germany
• Yeasts were developed and saved to give
better qualities of beer. Today beer making is
also a quite sophisticated process.
• The three main ingredients are barley malt,
hops and water.
• As much as 7.5 X 109 liters of beer are made
per year (2 X 109 gallons).
Malt
• Malt is sprouted grain that has been dried.
• Barley (Hordeum vulgare, Poaceae or
Gramineae), is preferred for several reasons.
The husks stay on the kernels and add some
of the flavor. Also, barley contains higher
concentrations of the enzymes needed for
converting starches into sugars.
• The grain is steeped in water and
allowed to sit where it is warm until
germination begins. The grain
synthesizes hydrolytic enzymes that
convert starch to sugar. The cell walls of
the endosperm break down. The
mixture is then dried at 130 to 200 C.
The brewing process
• See diagram p. 493.
• The process is now highly mechanized.
• The malt is extracted at 68-73 °C for 2-6
hours, a process called mashing. During
mashing, the enzymes diffuse into the
solution and break down the starch in
the malt and the adjuncts. Proteins are
degraded into amino acids.
The malted grain is
dried, milled, mashed,
and strained.
Adjuncts are added at
this stage.
Anheuser Busch Brewing Co., St. Louis
Adjuncts
• Adjuncts are unmalted grains that are added.
Barley, rice, wheat, or corn grits are often
used.
• In other countries, potatoes or cassava may
be used.
• Adjuncts are commonly used in the U.S., but
usually not in Europe. They are less
expensive than barley malt. Corn and rice are
both precooked before being added.
The wort is made by
boiling the extracted
malt mixture with
hops.
Anheuser Busch Brewing Co., St. Louis
Hops (Humulus lupulus, Cannabaceae)
• Hops (Humulus lupulus, Cannabaceae) were
only added to beer after 700 A.D.
• The English only started adding them in the
1500's. Sometimes other plants were added
for flavoring before that time. Hops not only
add flavor but help to coagulate and
precipitate proteins.
• The female inflorescences are used. They
contain a glandular exudate with the flavor
properties.
Hops, Humulus lupulus, Cannabaceae, fruits
Hops in cultivation in
Kent, England
•
•
•
•
Hops are then added and the liquid boiled.
This boiling step does several things.
The yeasts present are killed.
Compounds in the hops are converted to
bitter tasting compounds.
• The resulting liquid, called wort,
contains sugars, some starches,
proteins and amino acids, among other
components.
• The spent malt and adjuncts often are
used for cattle feed.
• In the process of making the wort, enzymes in
the mixture are denatured.
• Compounds in the hops are converted into
the compounds that give beer its bitter taste.
The hops are then removed.
• The liquid is pumped to fermentation tanks
and yeast is added.
• Saccharomyces cerevisiae is a top
fermenting yeast and S. uvarum is a bottom
fermenting yeast. The latter is used to make
ales and lager beers.
Fermentation and aging
of beer
Anheuser Busch Brewing Co., St. Louis
• Carbon dioxide is captured and is a major
byproduct of brewing.
• The mixture is allowed to ferment for 7-12
days at cool temperatures.
• The resultant liquid is transferred and allowed
to age for 2-3 weeks.
• Proteins precipitate out and some other
chemical modifications take place.
• In the U.S., most of the beers are
pasteurized or micropore filtered to
remove yeasts. The beer is usually
carbonated.
Sake
• Sake is made from rice and is a traditional
beverage in Japan. It is a fermented grain
beverage.
• Aspergillus oryzae is used to convert the
starch to sugar and then yeast added. Both
are involved in the fermentation process.
• The mixture is fermented for about 25 days.
• The alcohol content is about 18-19%. The
beverage is allowed to mature for about 40
days. It is consumed before 1 year.
Pulque
• Pulque is made by fermenting the juice
of Agave species, especially A.
americana. Pulque made from Agave
tequilana is distilled to produce tequila.
Maguey, Agave americana, Agavaceae
http://commons.wikimedia.org/wiki/Image:Agave_americana.jpg
Collecting the agua
miel with an ocote
Transferring the aqua miel for transport
Filtering the aqua miel prior to fermentation
Chicha
• Chicha is made by chewing cassava or corn
and spitting the materials into a tank or
container. The mixture is then allowed to
ferment. The saliva serves as a source of
amylase to break down starches. This
beverage is found in many areas of western
South America.
“Mash” and fermentation of
chicha in Peru
Courtesy Dr. Memory Elvin-Lewis
Dr. Memory ElvinLewis with a bowl
of chicha in Peru
Courtesy Dr. Memory Elvin-Lewis
Other alcoholic beverages
• Kvass is made from fermented bread, barley
or rye. It is sometimes peppermint flavored
and is popular in the former Soviet Union.
• Sorgo is made from fermented sorghum in
Africa.
• Pombe beer is made from bananas in
Uganda and eastern Africa.
Distillation
• Distillation involves converting components to
the vapor phase and then condensing them.
• The Arabs probably discovered this process.
They distilled perfume components and other
mixtures of fermented materials.
• Many of these substances were prepared for
medicinals.
Brandies
• Brandies are distilled wines.
• The most famous come from France. Cognac
is one type.
• The fermented juices of many other fruits are
also distilled.
• Liquers differ from brandy in that various
flavoring agents are added. They have sugar
and syrups added.
Alembics for distilling
wine to make brandy.
• By the 15th century, the English and Scots
had begun distilling barley beer and, in the
16th century, cognac was prepared in France.
Whiskeys were made in a similar way.
• Once distilled, the mixture is diluted back to
about 50% alcohol in general. Whiskeys are
aged in (usually oak) barrels.
• The inside of these barrels is often charred.
The barrel provides some of the flavoring
materials.
• Scotch whiskeys have a characteristic taste
because of the smoking process (over peat)
used to dry the malt.
• Bourbon whiskey is made from corn as the
primary grain (Zea mays, Poaceae) and was
developed by the early Scottish (many of
whom are called Scots-Irish) immigrants in
Pennsylvania.
• These whiskies are aged for at least two
years in new, charred oak barrels.
Aging of whiskey in charred white oak barrels
Other distilled beverages
• Gin and vodka are distilled to a high
percentage of alcohol and in the case of gin,
Juniperus communis, Cupressaceae,
"berries" are added.
• These beverages can be distilled from almost
any fermented mixture including potatoes,
grains, etc.
• Rum is made from fermented molasses or
sugar cane juice.
Tequila and mescal
• Tequila and mescal are distilled from
pulque made from various Agave
species.
Cultivation of Agave tequilana in Jalisco, Mexico
Field of agave and
“hearts” removed
from mature plants.
Courtesy Dr. Beryl Simpson
Hearts of agave on
way to distillery.
Steamed hearts ready to be fermented and distilled.
Courtesy Dr. Beryl Simpson