I have been investigating direct steam heating of the mash and from what my boiler people are telling me is that if I wanted to make the steam safe to inject into the mash that I would have give up the buffers that are carried with the steam that would protect the condensate return system,and the jackets and piping would break down more quickly. I run a 3,000,000 btu boiler powering a 30 BBL brewhouse.