G. Zhekova, A. Dzhurmanski, M. Nikolova

Abstract. Thyme “German winter”, thymol type was investigated for yield essential oil in four stage: buttoning, full blossom, end blossom and 7 days after blossoming period. Essential oil contents changes from 0.28 to 0.41% in fresh inflorescence. In stage buttoning it has the lowest value but during full blossom the highest. Essential oil contents after drying increases to 3.3 times and reaches 1.32 –1.42%, to absolutely dry material 1.55% but essential oil yield has a decrease tendency with 5-10%. The quality and quantity composition of essential oil are saved without important change. It shows that Thyme “German winter” can be distilled fresh as well as dry form.