Dextrination is a dry acid thinning, carried out at very high temperature and low moisture content.  After heating and drying the starch, the required amount of acid is added and the starch is reacted over a period in order to obtain the desired viscosity level.  The reaction is influenced by temperature, time, acid amount and moisture.  During dextrination three reactions occur, hydrolysis and re-polymerization and trans-glycosidation.