alcohol beverages
TRANSCRIPT
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Lecture 20 – Alcoholic Beverages –
Beer, Distilled Beverages
Reading: Textbook, Chapter 14
In this lecture we will continue our discussion of alcoholic beverages and the plants associated with their
production by considering beer, as well as distilled beverages.
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Beer, Ale, Sake
Beers – made from fermented grains
Lager beers – bottom-fermenting yeasts
Ales, bitters - top-fermenting yeasts
Sake: rice “wine” – made from rice, Aspergillus fungusÆ
liberates sugar Æ higher concentration of alcohol (18%)
Chicha: starts with chewed kernels of corn
Pulque: uses sap of Agave (compare to tequila, below)
By definition, the starting material for beers is grain - this distinguishes these beverages from wines. The most
commonly consumed beers in our country are based on barley. A problem in producing any beer is to convertthe starches in the grain into sugars that can be metabolized by yeasts. In sake, this process utilizes another
fungus and produces a more potent beverage. The traditional beer of native american groups in Mexico starts
with corn to which saliva - with its enzymes that break down starch into sugar - is added by chewing.
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History of Beer
Ca 6000 yrs ago?
Sumerians – used much of their grain to make beer
Early brewing – linked to bread making
- Barley breads – made from sprouted grainÆ dough was
logical place for fermentation to occur
- Source of microbes not controlledÆ not always
Saccharomyces, so batches could vary greatly
Relatively Recent – Standardization of methods to produce beer
of consistently uniform quality
NOTE: beers made the traditional way can be highly nutritious
– “liquid bread” – have significant proteins, vitamins
Beer has been consumed for as long as written records have been kept.
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Beer Ingredients
1. Barley Malt
Barley – preferred because contains large amounts of
enzymes that convert starches to sugars
Malting: causing the grain to sprout, then drying it
- grain is washed 8-10 hrsÆ absorbs water
- grain sits in water ca 40 hrs
- water is drained; grain sits controlled room 6 daysÆ
production of amylases, enzymes that break downstarch; other processesÆ reduce cloudiness
- germination process stopped by heating
The process of malting involves a process that liberates the starch-converting enzymes that are naturally
present in the barley grain. It also adds flavor compounds that are produced by the heating process.
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Beer Ingredients
2. Hops – Humulus lupulus
(Cannabaceae)
Dioecious vine – female flowering
structures utilized
- provides flavor associated with
beer
- adds enzymesÆ coagulate
proteins, reduce cloudiness
- appears to have antibacterialactivity
NOTE: other plants have been
used to flavor beers
Although beers can be flavored in a variety of ways, the use of hops became standard at a time when
preservation of the brew was an important consideration.
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Beer Ingredients
3. Adjuncts
Unmalted grains – barley, rice, wheat; corn syrup; potatoes – contain starches that can be converted to sugar (economic
consideration – less expensive than malted barley)
Æ Light-flavored beer, preferred in U.S.
Beer produced this way will also have fewer proteins
4. Yeast – Saccharomyces uuvuram (lager beers); S. cerevisiae(ale)
5. Water – pH, mineral content – affect taste
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Beer Brewing – Basic Steps
1. MaltingÆ Liberate enzymes (diastatic power)
2. MashingÆ Enzymes convert starchÆ sugar
3. Drain liquid = wort
4. Add hops (flavoring)
5. FermentationÆ “green beer”
6. Aging (“lagering”)
7. Pasteurization/filtering8. Re-addition of carbon dioxide
9. Bottling
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Distillation
Water – boils at 100 C (212 F)
Ethanol – boils at 78.5 C (173.3 F)
Note: owning a still is illegal in
the U.S. and Canada!
Mixture is heated; ethanol gas is
driven off at lower temperature;
gathered in condenser – note, various
devices added to minimize water
vapor from escaping
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Distilled Alcoholic Beverages -
Whiskeys
Whiskey: made from malted barley, or malted barley + other grain
- proof = twice concentration of alcohol (90 proof = 45% alcohol)
Scotch: made from barley malt; aged in charred casks
Bourbon: from Bourbon Co., Kentucky – 51+% corn
Tennessee sour mash: similar to bourbon; filtered through charcoal
Rye: 51% rye grain
Straight whiskey: <80 proof; aged 2+ years in new charred barrels
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Other Distilled Beverages
Gin, Vodka – distilled to high percentage of alcohol
Gin: flavored with juniper “berries” (fleshy cones)
Vodka: malt, grains, potatoes (variously mixed)
Rum: distilled from molasses or sugar cane juice
Tequila, Mescal: Mexico, produced from Agave
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Wood Products - Charcoal
Goal: create low temperature combustion to drive off water and
volatile - basically distillation of carbon
Product: enriched carbon – burns at high temperature
Byproduct: nitrogen and sulfur oxides = pollution
Production of charcoal is a special aspect of wood technology.
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Charcoal Production
Charcoal production is important to a number of other products, such as spirits, and it is also practiced
intensively in tropical regions where it can represent a severe environmental threat.