no, it is totally fine.
need to be careful here. prior to the 1996 version of the nec, it was acceptable for frames of electric ovens, ranges, clothes dryers and their associated outlets to be bonded (grounded) to the neutral. this often resulted in three wires being brought to these pieces of utilization equipment but not an equipment grounding conductor. the neutral conductor played the role of both the neutral and the equipment grounding conductor. and a requirement was that the circuit had to originate at the service equipment (i.e. the main panelboard, where neutral and ground are tied together). in other words, it could not be wired back to a sub-panel served from the main panelboard, only wired to the main panel itself.
this installation described above is still allowed for existing circuits but even those have to meet some minimum criteria on conductor size, insulated conductors, etc. this is so if someone buys a new oven, they don't need to go through a gnarly re-wiring of the circuit. for any new circuits, absolutely not allowed to use this installation method, even for an oven, dryer or range. for a brew panel, it wouldn't be allowed anyway since a brew panel is not an oven, range or clothes dryer. if you want 120 and 240 at the brew panel, absolutely need to run two hots, a neutral and a ground out to it. this can be served from the main panelboard or a sub-panel.