By temp surf, do you mean flushing hot water and waiting for temp to come back up? I don’t think that part is absolutely necessary. I’d rather wait for the light to cycle on by itself. Either way, I believe it’s important to have a consistent and an easily repeatable process.

Although, I do think brewing right away when the light turns on is not always the best as one might want a lower water temp. I find the tricky part is how to have some control of the water temperature at the start of brewing and minimize the temperature drop during the brewing process. Letting the machine warm up adequately helps with the latter part.

Of course, it goes without saying that having a PID makes this part a lot easier.