Processing Factors and Control - Kilning Flashcards
What is the first phase of the kilning process?
Free drying
Free drying is the initial stage where moisture on the kernel surface is removed by airflow.
What are the three phases of kilning?
- Free drying
- Forced drying
- Curing
These phases help in controlling the drying process of malt.
What parameters are measured to control the kilning process?
- Air-on temperature
- Air-off temperature
- Relative humidity (RH)
These parameters help monitor the effectiveness of the drying stages.
True or False: RH is always measured by all maltsters.
False
RH probes can become inaccurate when dusty, leading some maltsters to omit this measurement.
What is the air-on temperature range used during the free drying phase?
50-60˚C (as low as 40˚C for highly enzymatic malt)
This temperature range is effective for removing moisture from the malt.
What is the significance of latent heat in the drying process?
It is the energy required to break the links between water molecules, turning water into vapor
Latent heat is crucial for evaporating moisture from the grain surface.
What occurs at the break point during the forced drying phase?
The moisture on the surface of the grain has been evaporated, causing air-off temperature to rise
The break point marks the transition from free drying to forced drying.
What is the typical air-on temperature during the curing phase for lager malts?
78-85˚C
Curing is crucial for developing color and flavor compounds in malt.
Fill in the blank: The period where the malt moisture approaches 5-8% is called _______.
Curing
Curing involves high temperatures and is essential for flavor development.
What happens to the malt after the curing phase?
It is cooled down to around 30˚C
Cooling is important to prevent additional color pick-up and excessive moisture removal.
What is the drying front in the kilning process?
The progression of drying from the bottom to the top of the malt bed
The drying front indicates different drying stages within the malt bed.
What is the final step after the malt is cooled in the kiln?
It undergoes the deculming process to remove dried rootlets
This is followed by a final cleaning stage to eliminate dust and foreign material.
How does the air-off temperature change during the forced drying phase?
It rises closer to the air-on temperature and RH decreases
This indicates that the moisture has been effectively removed from the grain surface.
What is the effect of recirculating high humidity warm air during the free drying stage?
It damages the malt enzymes
High humidity can adversely affect the enzymatic activity in the malt.
What compounds are formed during the curing phase?
Characteristic color and flavor compounds, including DMS from SMM
This phase is critical for developing the desired attributes in malt.
What is the importance of controlling fan speed and drying air temperature?
They are the main process elements that affect air-on and air-off temperatures and RH
Proper control of these elements ensures effective drying.
