Abundance ratios of several detected molecules (colored datapoints) with respect to the total column density of H₂O derived from the pure rotational lines (cold + warm components) toward B1-c. The datapoints of ¹³CO₂ and ¹³CCH₂ are multiplied by 70 to take into account the ¹²C/¹³C ratio of the local ISM (Milam et al. 2005). The range of column density ratios detected in the ices for all low-mass protostellar systems (i.e., not limited to B1-c or other JOYS sources) are displayed as the shaded colored area for each species with a confirmed ice detection (Boogert et al. 2015; Rocha et al. 2024; Chen et al. 2024).