Unit 1 - Malt - Germination

Question 1

What is the main function of enzymes during germination?

Answer 1

To break down structures of the endosperm, including cell walls and starch granules

Enzymes involved include β-glucan solubilase, α-amylase, and β-amylase.

Question 2

What are the two forms of starch found in barley granules?

Answer 2

• Amylose
• Amylopectin

Question 3

What is the role of β-glucan solubilase in germination?

Answer 3

Breakdown of protein links that keep β-glucan chains rigid and insoluble

Question 4

What must be degraded to expose starch granules during germination?

Answer 4

The protein matrix surrounding the starch granules

Question 5

What are the two types of proteases involved in protein breakdown?

Answer 5

• Endoproteases
• Exoproteases

Question 6

What is the significance of the balance in protein breakdown during germination?

Answer 6

Too little leads to incomplete modification; too much destroys proteins needed for beer foam.

Question 7

What enzymes are responsible for starch breakdown?

Answer 7

• α-Amylase
• β-Amylase
• Limit dextrinase

Question 8

Fill in the blank: The enzyme that converts phytic acid to phosphate in barley is called _______.

Answer 8

Phytase

Question 9

What is the main function of lipases during germination?

Answer 9

Breakdown lipids to produce fatty acids for energy and new plant cells

Question 10

What compound does lipoxygenase oxidize, leading to stale beer flavor?

Answer 10

Linoleic acid

Question 11

What is gibberellic acid (GA) and its role in germination?

Answer 11

A hormone that stimulates enzyme production during germination

Question 12

List two properties that increase due to gibberellic acid (GA).

Answer 12

• Extract
• Soluble proteins

Question 13

List two properties that decrease due to gibberellic acid (GA).

Answer 13

• Germination time
• Colour

Question 14

What is the traditional method of germination called?

Answer 14

Floor maltings

Question 15

What is the function of the helical screws in modern Saladin boxes?

Answer 15

To turn the grain bed and prevent matting

Question 16

What temperature range is typically maintained in the grain bed during germination?

Answer 16

16-21˚C

Question 17

What is the effect of moisture on germination and enzyme activity?

Answer 17

Increasing moisture increases the rate of modification and enzyme activity.

Question 18

Fill in the blank: The acrospire growth test is used to measure the extent of _______ during germination.

Answer 18

Modification

Question 19

What does a length measurement of > 1 for acrospires indicate?

Answer 19

Over modification of the kernels

Question 20

What are two quality checks that can be performed during germination?

Answer 20

• Moisture content analysis
• Visual analysis

Question 21

What is the role of temperature control during germination?

Answer 21

To maintain optimal enzyme activity and prevent overheating

Question 22

What is the consequence of high CO2 levels during germination?

Answer 22

Reduces the rate of germination

Question 23

What is the purpose of water spray nozzles during germination?

Answer 23

To maintain bed moisture

Question 24

What is the significance of the protein matrix density in barley grains?

Answer 24

Higher density can make grains resistant to protein-degrading enzymes.

Question 25

What is the primary purpose of α-amylase during starch breakdown?

Answer 25

To randomly break glucose links within the starch molecule.

Question 26

What is the role of limit dextrinase in starch breakdown?

Answer 26

To break the branch points of amylopectin, creating shorter chains.

Question 27

What is the effect of climatic conditions on amylase levels in barley?

Answer 27

Can affect the production of α- and β-amylases.

Question 28

What range indicates that acrospires are either dead or growing slowly?

Answer 28

0-1/4 ## Footnote Acrospires are the shoots that emerge from the germinating grain.

Question 29

What is the significance of having acrospires the same length?

Answer 29

It helps ensure the finished malt is uniform across the batch.

Question 30

List three quality checks that can be carried out during germination.

Answer 30

* Moisture content analysis * Acrospire growth * Visual analysis

Question 31

What does visual analysis involve?

Answer 31

Rubbing grains between your thumb and forefinger.

Question 32

What does it indicate if the starchy endosperm looks like chalk on your fingers?

Answer 32

The green malt is correctly modified.

Question 33

What happens if there is still cell wall material present when rubbing the grains?

Answer 33

It forms little balls, indicating the malt is under modified.

Question 34

How long does barley typically spend in the germination vessel?

Answer 34

Four to six days.

Question 35

What can over modification reduce?

Answer 35

Extract levels.

Question 36

What issues can arise from the friable nature of over modified grain?

Answer 36

Grain can shatter, leading to dust losses and finer grist than required for wort separation.

Question 37

What problems can under modified grain cause in the brewhouse?

Answer 37

Problems in filtration due to undegraded β-glucans.

Question 38

What continues to happen during the first couple of hours of kilning?

Answer 38

The grain continues modification.