Once germination is complete the green malt is transferred to the kiln, where it is dried. The main objectives of kilning are to stop the germination process, remove moisture in the grain down to a suitable moisture content for safe storage, to stabilise the enzymes produced during germination and to impart essential characteristics of the finished malt, such as moisture, colour and flavour.
During the kilning process free drying takes place, initially, where moisture from the surface of the grain is removed by blowing air at low temperatures and high air flow up through the bed. This ensures the survival of the enzymes contained in the grain so that the brewer and distiller can reactivate them again during the mashing process. Free drying reduces the moisture in the grain down to approximately 25%. Forced drying is the next stage, where water migrates from the centre of the grain to the surface at higher temperatures At the end of this stage, the moisture is less than 10%.
The final stage in the kilning process is curing, where moisture is reduced to less than 5% and the grain can be safely stored until requested by the brewer or distiller. The curing stage is where the majority of flavours, aromas and colour are produced. Varying the amount of drying time, temperature and other methods, like roasting, enable us to create variations in the flavour and colour of the malt to produce our specialty malts such as caramalt, crystal and chocolate to name but a few.