Barley/Malt Flashcards
What are the two varieties of barley grain?
- 2-row
- 6-row
What is the minimum and maximum size required for barley grain?
2.5 mm minimum
No maximum
How is protein content of barley estimated?
Protein = Total Nitrogen x 6.25
What is germinative capacity of barley?
It indicates the amount of barley that will eventually germinate
What is germinative energy of barley?
It indicates the amount of barley to germinate after 3 days
What does staining with fluorescein dibutyrate indicate for barley?
It indicates if the barley has sprouted. You do not want the barley to begin sprouting prior to the malting process
What is the target for total moisture of barley?
<12.0%
What is the target for B-glucans in barley?
4.0%
What is DON and what is the target for barley?
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
How much of the barley is typically composed of starch? What are the 2 starches?
60-65%
Amylopectin (70-78%)
Amylose (20-30%)
How much of the barley is typically composed of proteins?
9-13%
What are the 3 classes of proteins?
- Structural proteins
- Storage proteins
- Metabolic and protective proteins
What is proline?
Why is it important?
Where is it found?
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
What is FAN?
Why is it important?
What is the target for barley (mg/100g)
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
How much of the barley is typically composed of non-starch polysaccharides?
What are the 2?
Where are they found?
3-5%
B-glucan
Arabinoxylan
Found in the cell walls
What are B-glucans and arabinoxylans hydrolyzed by during malting?
B-glucanase
Xylanase
What is the impact of having a higher amount of non-starch polysaccharides in barley?
Harder texture in the cell wall
More difficult to malt
How much of the barley is typically composed of polyphenols?
What does this contribute to the beer?
3%
- Antioxidant properties
- Haze
- Ferulic acid to 4-vinylguiacol during fermentation (gives the clove spice)
How much of the barley is typically composed of lipids?
What do they contribute to the beer?
2-3%
Lipids have a negative effect on beer foam
Produce off flavors
Do support some fatty acids for yeast metabolism
What is the target for barley extract (course, % as is)?
77-78%
What is friability of malt?
What is the target?
The ability for the malt to be milled, indicates the modification level of the malt
90-92%
What is the target for alpha amylase (DU) for barley?
For wheat?
50
80
What is the target for Diastatic Power in malt?
Why is this important?
150-200
DP is proportional to B-amylase
What is the Falling Number test for barley?
- 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
What are the 3 grades of barley sizing and what are they used for?
- 1st grade which are plump grains and used to produce standard base malts
- 2nd grade which are thinner/smaller grains and my be used for specialty malts
- 3rd grade which are too thing to malt and are usually sold for feed barley
What the 4 reasons we need to dry barley grain?
- Leads to mold on the grain
- Leads the grain to respire which produces heat and condensation in the silo
- Lead to hot spots in the silo
- If temperature is too high, the embryo will die and result in poor germination
What is the Kolbach Index for barley?
What is the target?
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
What is the function of alpha amylase enzymes in barley?
Cuts glucose molecules apart randomly into smaller molecules
What is the function of B-amylase enzymes in barley?
Cuts off 2 glucose molecules at a time from larger molecules to make maltose molecules
What is the function of limit dextrinase enzymes in barley?
Cuts the 1-6 bonded branches from glucose chains that are longer than 6 molecules
On the left is an active protein. What is pictured on the right? What has caused this?
A denatured protein
This is caused by excessive heat
This renders the protein inactive
During which stage of malting are proteases synthesized?
What is their purpose?
Proteases are synthesized during germination.
They cut up larger polypeptides into smaller peptides
What is the purpose of peptidases during the malting process?
Peptidases cut smaller peptides into individual amino acids.
Which two amino acids make up the majority of amino acids in barley?
- Glutamine
- Proline
What is the purporse of steeping in the malting process?
Steeping the barley increases the moisture of the grain and kickstarts the biological processes needed for germination
How long does a typical steep last?
How many steep/air rest cycles are required?
24-48 hours
Consists of 2-3 steep/air rest cycles
What does this graph depict?
A typical steeping cycle for barley
Higher protein content will increase or decrease the rate of barley germination during the malting process?
What is the ideal protein content?
Decrease
Ideal protein is 10-11%
How long does a typical germination phase last?
4-6 days
How long does a typical kilning phase last during the malting process?
~24 hours
What is the final target moisture content of malt after kilning?
4-4.5%
What are the 4 objectives of kilning in the malt process?
- Drying the malt
- Stabilize reactions
- Add color to malt
- Add flavor to malt
What is the name of the reactions that take place in the kiln during the malting process that produce flavors and color?
Maillard Reactions
What extra step is needed to make specialty malts?
Roasting of the malt after kilning
When analyzing malt quality, what should be the target for difference between the fine and course extracts?
<1%
What is °P?
What does a 20°P wort represent?
°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
How do you convert between °P and SG?
How many °P is equal to a SG of 1.060?
1.060 SG = 15°P
The viscosity of wort is proportional to the concentration of B-glucans.
True of false?
True
What is this molecule?
What is the significance of the red end?
This amylopectin starch
The red end is the single reducing end of the molecule
Why is it so important to cool malt after the kilning process?
