Tests before steeping Flashcards
What is the purpose of the germinative capacity (GC) test?
To check if barley has the ability to germinate
The GC test is usually undertaken when barley is delivered to the malt plant to check whether it is acceptable for intake.
How is the germinative capacity (GC) test conducted?
100 grains are cut longitudinally and stained with a tetrazolium dye
Living embryos stain pink, while dead embryos remain white or discolored.
What does a GC test result indicate?
The percentage of living barley grains
A result > 98% is preferred, ideally 100%.
What is the germinative energy (GE) test?
A test to determine the ability of barley grains to germinate
Involves checking 100 wetted grains for rootlet growth over three days.
What is the difference between germinative capacity (GC) and germinative energy (GE)?
GC measures living grains; GE measures germination ability
The difference indicates dormancy levels.
What is dormancy in barley grains?
A protective mechanism preventing premature germination
It varies by variety and is reduced over time or through drying heat.
What is the significance of high dormancy in newly harvested barley?
It prevents germination after rainfall on the mature plant
High dormancy requires longer storage until it breaks.
What is water sensitivity in barley grains?
A condition where grains do not germinate in excess water
It is tested by comparing germination in 4 mL vs. 8 mL water.
How is water sensitivity calculated?
Water sensitivity = number of germinated grains in 4 mL test - number of germinated grains in 8 mL test
Important to test before steeping to ensure good germination.
What happens to water sensitivity during grain storage?
It declines or disappears in most varieties
Some varieties remain water sensitive even after storage.
What action is taken if barley is found to be water sensitive?
Use a modified steeping process with longer air rests
Necessary to ensure proper germination.
What is the role of steeping in the malting process?
To prepare the grain for germination
Changes occur in the grain during steeping.
