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MBCP 2021 > Barley/Malt > Flashcards

Barley/Malt Flashcards

1
Q

What are the two varieties of barley grain?

A
  1. 2-row
  2. 6-row
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2
Q

What is the minimum and maximum size required for barley grain?

A

2.5 mm minimum

No maximum

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3
Q

How is protein content of barley estimated?

A

Protein = Total Nitrogen x 6.25

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4
Q

What is germinative capacity of barley?

A

It indicates the amount of barley that will eventually germinate

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5
Q

What is germinative energy of barley?

A

It indicates the amount of barley to germinate after 3 days

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6
Q

What does staining with fluorescein dibutyrate indicate for barley?

A

It indicates if the barley has sprouted. You do not want the barley to begin sprouting prior to the malting process

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7
Q

What is the target for total moisture of barley?

A

<12.0%

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8
Q

What is the target for B-glucans in barley?

A

4.0%

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9
Q

What is DON and what is the target for barley?

A

DON is a toxin produced by fungi in barley. If present, the barley will have a pink color. The target should be 0 mg/kg

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10
Q

How much of the barley is typically composed of starch? What are the 2 starches?

A

60-65%

Amylopectin (70-78%)

Amylose (20-30%)

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11
Q

How much of the barley is typically composed of proteins?

A

9-13%

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12
Q

What are the 3 classes of proteins?

A
  1. Structural proteins
  2. Storage proteins
  3. Metabolic and protective proteins
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13
Q

What is proline?

Why is it important?

Where is it found?

A

It is an amino acid but cannot be utilized by yeast. It is found abundantly in the sequences of hordeins which is a storage protein of barley

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14
Q

What is FAN?

Why is it important?

What is the target for barley (mg/100g)

A

Free Amino Nitrogen

It is released during malting by action of peptidases

It supports the Maillard reactions which produce flavors during the kilning in the malting process

150-200 mg/100g malt

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15
Q

How much of the barley is typically composed of non-starch polysaccharides?

What are the 2?

Where are they found?

A

3-5%

B-glucan

Arabinoxylan

Found in the cell walls

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16
Q

What are B-glucans and arabinoxylans hydrolyzed by during malting?

A

B-glucanase

Xylanase

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17
Q

What is the impact of having a higher amount of non-starch polysaccharides in barley?

A

Harder texture in the cell wall

More difficult to malt

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18
Q

How much of the barley is typically composed of polyphenols?

What does this contribute to the beer?

A

3%

  • Antioxidant properties
  • Haze
  • Ferulic acid to 4-vinylguiacol during fermentation (gives the clove spice)
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19
Q

How much of the barley is typically composed of lipids?

What do they contribute to the beer?

A

2-3%

Lipids have a negative effect on beer foam

Produce off flavors

Do support some fatty acids for yeast metabolism

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20
Q

What is the target for barley extract (course, % as is)?

A

77-78%

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21
Q

What is friability of malt?

What is the target?

A

The ability for the malt to be milled, indicates the modification level of the malt

90-92%

22
Q

What is the target for alpha amylase (DU) for barley?

For wheat?

A

50

80

23
Q

What is the target for Diastatic Power in malt?

Why is this important?

A

150-200

DP is proportional to B-amylase

24
Q

What is the Falling Number test for barley?

A
  • Milled flour is mixed with water in a large test tube
  • A plunger is placed on top of the of the slurry and allowed to fall
  • The time that it takes for the plunger to reach the bottom is measured and get the Falling Number
  • Grain that is germinated will have alpha amylase enzyme that already started breaking up the starch which makes the slurry less viscous and allows the plunger to fall faster
  • Falling Number <300 s indicates pre-germination
25
Q

What are the 3 grades of barley sizing and what are they used for?

A
  1. 1st grade which are plump grains and used to produce standard base malts
  2. 2nd grade which are thinner/smaller grains and my be used for specialty malts
  3. 3rd grade which are too thing to malt and are usually sold for feed barley
26
Q

What the 4 reasons we need to dry barley grain?

A
  1. Leads to mold on the grain
  2. Leads the grain to respire which produces heat and condensation in the silo
  3. Lead to hot spots in the silo
  4. If temperature is too high, the embryo will die and result in poor germination
27
Q

What is the Kolbach Index for barley?

What is the target?

A

Kolbach Index is the amount of soluble nitrogen divided by the total nitrogen in the malt. It is an indication of the modification of the malt.

The target is 40-46.

<40 is undermodified

>46 is well modified

28
Q

What is the function of alpha amylase enzymes in barley?

A

Cuts glucose molecules apart randomly into smaller molecules

29
Q

What is the function of B-amylase enzymes in barley?

A

Cuts off 2 glucose molecules at a time from larger molecules to make maltose molecules

30
Q

What is the function of limit dextrinase enzymes in barley?

A

Cuts the 1-6 bonded branches from glucose chains that are longer than 6 molecules

31
Q

On the left is an active protein. What is pictured on the right? What has caused this?

A

A denatured protein

This is caused by excessive heat

This renders the protein inactive

32
Q

During which stage of malting are proteases synthesized?

What is their purpose?

A

Proteases are synthesized during germination.

They cut up larger polypeptides into smaller peptides

33
Q

What is the purpose of peptidases during the malting process?

A

Peptidases cut smaller peptides into individual amino acids.

34
Q

Which two amino acids make up the majority of amino acids in barley?

A
  1. Glutamine
  2. Proline
35
Q

What is the purporse of steeping in the malting process?

A

Steeping the barley increases the moisture of the grain and kickstarts the biological processes needed for germination

36
Q

How long does a typical steep last?

How many steep/air rest cycles are required?

A

24-48 hours

Consists of 2-3 steep/air rest cycles

37
Q

What does this graph depict?

A

A typical steeping cycle for barley

38
Q

Higher protein content will increase or decrease the rate of barley germination during the malting process?

What is the ideal protein content?

A

Decrease

Ideal protein is 10-11%

39
Q

How long does a typical germination phase last?

A

4-6 days

40
Q

How long does a typical kilning phase last during the malting process?

A

~24 hours

41
Q

What is the final target moisture content of malt after kilning?

A

4-4.5%

42
Q

What are the 4 objectives of kilning in the malt process?

A
  1. Drying the malt
  2. Stabilize reactions
  3. Add color to malt
  4. Add flavor to malt
43
Q

What is the name of the reactions that take place in the kiln during the malting process that produce flavors and color?

A

Maillard Reactions

44
Q

What extra step is needed to make specialty malts?

A

Roasting of the malt after kilning

45
Q

When analyzing malt quality, what should be the target for difference between the fine and course extracts?

A

<1%

46
Q

What is °P?

What does a 20°P wort represent?

A

°P = degree Plato

It is a w/w % of a sugar solution

20°P wort would have 20 g of sugar per 100 g wort

47
Q

How do you convert between °P and SG?

How many °P is equal to a SG of 1.060?

A

1.060 SG = 15°P

48
Q

The viscosity of wort is proportional to the concentration of B-glucans.

True of false?

A

True

49
Q

What is this molecule?

What is the significance of the red end?

A

This amylopectin starch

The red end is the single reducing end of the molecule

50
Q

Why is it so important to cool malt after the kilning process?

A

MBCP 2021 (18 decks)

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