Yes, a hollandaise and a bernaise (and some others) CANNOT be made on an open burner, no matter how low. Although, I have yet to try a burner that (allegedly) can do a 140 degree simmer, and maybe that would work. If I could have everything I wanted in life, I would have a simmer plate. But I would also have an apartment at 4 East 66th Street and 50 suits from a certain obscure but brilliant tailor. It's not gonna happen, so there is no point in dwelling on it.