Alcohol Beverages

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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.