In conclusion, in this paper we demonstrate the growth of columnar lithium layers up to 30 µm in thickness, through the use of water as an additive. We show that this morphology can be grown using both non-hydrolysing (LiTFSI) and fluorine-free (LiClO4) electrolytes, proving that a LiF SEI derived from electrolytes containing HF cannot be considered as the governing factor for this growth mode, as is often advocated in literature. Furthermore, we test an alternative hypothesis that relies on the formation step (potentials above 0 V vs. Lithium) for the columnar growth and find that this is also not consistent with our results. Rather we find that the water additive plays a continuous role in guiding the electroplating and should be balanced with the deposition rate. Finally, we investigate the growth process using a rotating ring disk electrode and observe that hydrogen is continuously present during growth. Based on these results we consider molecular hydrogen to be the critical component for columnar lithium growth, which homogenizes our results with literature on HF based electrolytes that also produce hydrogen during electrochemical reduction. We put forth a tentative mechanism for the role of hydrogen, through the combination a LiH containing surface layer, and/or by means of nanobubble templating. Overall, our results provide mechanistic insights on the growth of this particular lithium topography. Further design and control over such columnar lithium metal layers could enable the use of their unique plating/stripping behavior along the length of the column, which can potentially mitigate well-known failure mechanisms of high local current densities and large volumetric changes in lithium metal anodes. For the RRDE experiments an MSR rotator was used with an E6R1 ChangeDisk electrode (Cu disk, Pt ring, Pine Research). A glass beaker was used for the RRDE experiments, which was cleaned with acid piranha before every experiment and brought into the glovebox after vacuum drying in the antechamber (no heating). After every experiment the RRDE was polished on a rotating table with a polishing cloth and sequentially using a 3 µm, 1 µm, and 0.25 µm diamond suspension (Dia-complete poly, QATM).