I could have sworn there is an episode in DS9 which shows or says the replicators use a jell from which everything is replicated, and to which all things are de-replicated into. I thought that episode might be DS9: "Babel" but when it shows inside the guts of the replicator there is only a tube full of red, bubbling liquid. The closest "Babel" gets is when Kira says all the replicators have bio filters to screen out contaminants and viruses. That would only be needed if replicators are just rearranging matter into a new form, more like a teleporter, rather than making matter from energy and vice versa. Is there an episode which shows or says replicators use some sort of bulk material, rather than turning energy straight into matter?