Alcohol Beverages

7/28/2019 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.



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.



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.



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.



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.



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



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



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



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



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



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.



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.

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Alcohol Beverages