Control Of Fermentation Flavors

Question 1

Name 5 fermentation flavor compounds

Answer 1

Acetaldehyde 
Diacetyl 
Esters
Phenols
Fusel Alcohol 
Sulfer
Autolysis

Question 2

How many flavor compounds have been identified in beer

Answer 2

950

Question 3

How can higher alcohols be reduced in fermentation

Answer 3

Higher pitching rate
Cold pitching and fermentation temps
CO2 pressure during fermentation
Avoid O2 after pitching
Yeast strain selection

Question 4

What is the flavor of isoamyl acetate

Answer 4

Banana or pear

Question 5

List 4 factors affecting ester production

Answer 5

Wort gravity (higher P, higher esters)
Fermentation Temp
Pitching rate
O2 levels
Zinc
Fermentation pressure

Question 6

If beer has high diacetyl after fermentation, what can be done to reduce it?

Answer 6

Allow the beer to sit on the yeast for 2-3 days

Question 7

What common taste attribute do organic acids have?

Answer 7

Sourness

Question 8

Are fatty acid flavors desirable in beer

Answer 8

Generally not, but some styles may call for it in the form of 4VG or Diacetyl

Question 9

What is yeast autolysis?

Answer 9

Stressed yeast that eventually ruptures its cell walls, releasing proteolytic enzymes into the beer.

Question 10

If pressure is increased in fermentation, will the following attribute levels rise or fall?

Answer 10

Acetaldehyde (rise)

Dissolved CO2 (rise)

Diacetyl (rise)

Esters (fall)

Higher / Fusel alcohols (fall)