The determination of aging indicators in beer records volatile substances that undergo a significant increase during the storage of bottled beer as a function of the temperature and oxygen content of the beer. From the increase in the aging components during storage, in combination with the sensory analysis of the beer, a statement can be made about the flavor stability.
The method is suitable for the determination of steam-volatile aging indicators in beer.
Volatile aging indicator substances are driven out of the sample through steam distillation. The ethanol distillate is adjusted to be alkaline and saturated with NaCl. The extraction of the aroma compounds is performed by shaking out with dichloromethane and the phases separated by centrifuging. The organic phase is further concentrated in a stream of nitrogen gas. Ammonia solution is added to remove the acids, as the acids would coelute, thus preventing the quantification of important substances.