Cultures and Propagation

Question 1

What is a pure culture?

Answer 1

Single strain of yeast species grown in isolation from any other strains or contaminants

Question 2

What ph level does the phosphoric acid need to be for acid washing?

Answer 2

2.2 to 2.5

Question 3

What is viability?

Answer 3

Refers to ability of cells to reproduce

Question 4

What is vitality?

Answer 4

Metabolic activity, fermentation performance and stress resistance

Question 5

What are the reasons for propagation?

Answer 5

Produce sufficient yeast in good physiological condition
Avoid mutations
Minimize contamination
Prevent problems

Question 6

What is yeast pitching?

Answer 6

Inoculation of yeast cells into fresh wort

Question 7

What are the most frequent mutations in brewing yeasts?

Answer 7

Petite (stress induced)

Question 8

What are key considerations for laboratory propagation?

Answer 8

Aseptic technique
Steril growth media
Aeration
Temperature

Question 9

What are key considerations for plant propagation?

Answer 9

Wort
Temperature
Time
Contamination
Conditions