The degree of decomposition for peat can be understood as the relative proportion of humification products of the entire peat substance. The definition continues with a scale of one to ten, the von Post humification method. One represents not decomposed material with visible plant structures and ten represents completely decomposed material with no longer recognizable structures.

In the topmost strata of the bog, the mosses still have well recognizable structures. Sphagnum moss, also called pale moss due to its light color, has a faint, whitish appearance. The lower the stratum is, the darker the color gets. White peat is found in the topmost layers, brown peat in the transition layers and black peat in the oldest, undermost, highly decomposed layers of a bog.