Using ISIS facilities, our team has discovered three new phases of ice: ices XIII, XIV and XV. These phases form in the presence of small amounts of hydrochloric acid. Yet, the role the acid dopant plays is still very poorly understood. In particular since the preparation of ice XI from the ‘ordinary’ ice I requires base doping and acid doping is ineffective. Now, we have found using calorimetry and X-ray diffraction that ice XIII can also be prepared with lithium hydroxide doping. Since this is the first case where acid and base doping are effective, we now have the perfect system for finally clarifying the role of the dopants. In addition to complementary DFT calculations, the experimental key question is now if acid and base dopants facilitate the same structural pathways leading towards the same ice XIII end-state. This question can only be answered with neutron diffraction.