MALTING QUALITY TRAITS - Canadian Malting Barley Technical ...

14
Chapter Two
Malting Barley Handling and Storage
Malting barley, like other cereal grains, is frequently subjected to various physical and biological
damages during handling and while in storage. If damage is excessive, however, the barley will
lose its suitability for malt production. Although damage cannot be avoided completely, it can be
minimized through proper handling and safe storage.
Handling
The barley kernel is very brittle, especially when its moisture content is low. During the handling
process, the physical force applied to barley kernels may peel, crack and break them. Excessively
peeled and broken kernels could be a result of rough handling during the harvesting and conveying
processes.
Combining and Conveying
Improper combining is the most common reason for peeled and broken kernels.
The degree of kernel damage is associated with combine settings, combine cylinder speed,
barley kernel moisture content and the variety type. The variety type plays a significant role in the
barley kernel’s resistance to damage. As some malting varieties have a tougher husk, they are less
susceptible to physical damage.
For storage safety reasons, malting barley should not be combined if kernel moisture
is higher than 14.8%. On the other hand, if the kernels are too dry they will peel
and crack easily. Accordingly, farmers often combine malting barley in the early morning
and evening when humidity is relatively high. The combine should be adjusted to
eliminate chaff and weeds as much as possible without damaging the kernels. Generally, the
combine cylinder speeds should be set slightly slower than those used for harvesting wheat. Speed
requirements differ depending on the barley variety, kernel moisture content and the cylinder diameter.
All mechanical adjustments to the combine must be worked out by trial and error to ensure
a minimum degree of damage to the barley kernels.
Conveying is involved when grains are physically moved from one point to another.
If not conveyed carefully with suitable conveying equipment, severe kernel damage can
occur. The degree of damage depends on both the conveying method and the barley
condition, such as kernel shape and moisture content. ‘Screw and drag’ conveyers should
be used as little as possible, as they usually result in more damage than ‘belt and bucket’
conveyers. Although conveying by gravity and airflow is considered to be the safest
conveying method, damage can still occur if barley kernels are dropped from a great height, or if
passed through a pipe or chute too quickly. The best preventative measure is to keep barley movement
minimal, and to convey as gently as possible.
Safe Storage
Malting barley must be stored carefully in order to preserve its quality. It has always
been a challenge to find cost-effective storage that both preserves the barley’s quality
and is suitable for various climatic conditions. Although modern storage structures
effectively protect the barley from weathering, other biological and environmental
factors such as fungi, insects, rodents, ambient temperatures, relative humidity and
oxygen content can damage stored barley. To maintain quality and prevent malting barley loss, these potential
damages must be successfully controlled. In Canada, the cold and dry climate typical of the Prairie
provinces provides excellent conditions for barley storage without major concerns of fungal infection
and insect infestation. However, in countries with a hot and humid environment, various measures must
be taken to protect barley in storage from excessive fungal growth and insect infestation. The effects of
barley moisture content, fungal infection and insect infestation on barley quality are briefly discussed
on the next two pages.