Importance of the assessment of grain at intake to the maltings.
The need for such rigorous assessment should be clearly understood. Maltsters have to take a firm line at intake not only to ensure that they receive the grain that they have purchased, but also to be able to show that they have been duly diligent in meeting barley quality requirements. By these means subsequent malt quality and food safety standards can be met.
Barley has to grow evenly during the malting process to ensure high quality malt. Dead or dormant corns cause problems; they do not producing any usable extract (or spirit yield for distilling), and they can impair the quality of the finished malt.
UK Maltsters have therefore set a minimum standard for germinative capacity of 98% for barley to attain before it is accepted for malting.
In the UK, intake tests for germination are carried out by using a quick method, the tetrazolium staining test which takes about 10 minutes in total, and gives a germinative capacity result. This is an indication of what the germinative power of the barley is likely to be, that is ‘will it grow?’. The test entails cutting 100 grains along the ventral crease, then immersing them in a solution of tetrazolium under vacuum for 5 minutes. The embryo of growing corns will be stained red; dead corns remain white or may be discoloured. The trained eye can also detect dormant and pre-germinated grains by the degree of staining. Photographs of a range of results from tetrazolium staining tests can be viewed here
The germinative energy result is obtained by a visual check for rootlet growth on 100 wetted corns over 3 days. This test is used by maltsters to show how well the grain will grow if it is steeped.