/ RAW MATERIALS / Barley / Physiological Tests

R-110.34.612 [2016-03] Water Sensitivity in Barley

Germinative capacity

Germinative capacity is the most important characteristic of malting barley. It measures the percentage of viable kernels in a barley sample, independent of whether they are still dormant or not.

Germinative energy

Germinative energy measures the percentage of kernels in a barley sample, which would germinate under normal malting conditions at the time of the analysis.

A high value for germinative energy indicates that the barley is in good condition and therefore can be successfully malted.

Pre-germination (number of kernels exhibiting pre-germination)

Moist weather during the final maturation stage can cause germination to occur prematurely, while the barley is still in the field. The acrospire and rootlet develop, enzymes are produced and therefore extract is consumed (extract loss) and during the necessary drying process, germinative capacity is diminished. Floating tests and sectioning provide a certain amount of information with regard to pre-germination; however, staining methods allow the degree of hidden pre-germination to be determined. Additionally, the percentage of non-germinated and unmalted barley in malt can be established as well.

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Application/Purpose

This method describes the determination of water sensitivity in barley.

Scope of Application

Barley intended for the production of malt is evaluated on the basis of water sensitivity.

Principle

The 4 ml test measures the normal germinative energy of a barley sample. The 8 ml test provides information regarding the level of water sensitivity. During the steeping process, the water sensitivity of a barley sample must be taken into consideration. The duration of the air rest or dry-steep period must be extended with increasing sensitivity.

The water sensitivity is expressed as the difference between the germinative energy measured in the 4 ml and 8 ml tests.