According to the Völkenrode System, aerobic stability is still defined as the number of hours since the silage temperature rises by 2 ° C (or 3 ° C) above the ambient temperature. The quality of aerobic stability can also be assessed by other methods. These are: maximum silage temperature, pH at the beginning and end of the test, degree of condensation, degree of presence of yeasts and molds and weight loss of the silage. Corn silages tend to be less stable than alfalfa silages. An important task for the future is the unified European unification of the aerobic stability assessment methodology. It is necessary to unify the temperature and length of the test as well as the parameters of the test equipment.