Fraction of methanol-ice with respect to water-ice column density plotted as a function of the visual extinction A_V along the line of sight through the cloud. The gray curve shows the model calculations by Vasyunin et al. (2017) with an updated radial density profile and a reduced initial oxygen abundance (see text for details). The methanol to water-ice ratio observed on source 3 is marked by a horizontal yellow line, which denotes the full range of A_V measured by the different methods. The upper limits on the methanol-ice abundance are shown with downward arrows in light grayfor sources 1 and 5. The fraction of methanol ice detected toward star 3 is 4.5 times smaller than predicted by the models.