Section 2: Brewing

Question 0

Describe diacetyl

Answer 0

• buttery movie theater popcorn, butterscotch
• present at low levels in some English style ales
• common in dirty draft lines
• bacterial contamination
• leaks out of yeast cells during amino acid synthesis

Question 1

Name the major steps in the brewing process

Answer 1

1. Milling
2. Mashing
3. Lautering
4. Boiling
5. Whirlpooling
6. Cooling
7. Fermenting
8. Maturing
9. Filtering
10. Packaging
11. Distribution

Question 2

Describe Estery/ Solvent (ethyl acetate)

Answer 2

• fruity, nail polish remover
• created in boil
• brew house probs
• microbial infection
• found in high alcohol beer

Question 3

Describe Estery isoamyl acetate

Answer 3

• Banana, circus peanuts
• sign of yeast stress
• found in high alcohol beers
• ford during fatty synthesis
• common & desired in Bavarian weizens

Question 4

Describe 4-vinyl guaiacol

Answer 4

• clove, phenolic
• only in German weizens
• formed during fermentation if ferulic acid was formed durning malt kilning

Question 5

Describe 4-ethyl phenol

Answer 5

• “barnyard”/ Brett
• horsey
• appropriate in lambick, English style old ales and some saisons
• made by Brettanomyces yeast

Question 6

Describe acetaldehyde

Answer 6

• green apples
• should NEVER be detected
• symptom of too young “green” beer

Question 7

Describe butyric acid

Answer 7

• rancid butter
• should NEVER be detected
• in spent grains

Question 8

Describe isovaleric acid

Answer 8

• rancid butter
• should NEVER be detected
• in spent grains

Question 9

What is Brettanomyces and what does it do?

Answer 9

• yeast strain
• role in lambic, some saisons, and traditional English old ales
• barnyard aromas
• metabolizes maltose
• can be used to slowly ferment beer

Question 10

What are pichia and candida?

Answer 10

• type of yeast
• similar to sherry
• minor role in lambics
• occurs as spoilage organism

Question 11

What are lactobacillus and pediococcus?

Answer 11

• types of yeast

- sours lambics and Berliner Weisses

Question 12

What is acetobacteria?

Answer 12

• type of yeast
• vinegar and pickle aromas
• common in oak aged beers
• important aromas of lambics➡ Flanders style red/ brown ales