system
Given the following post, respond as if you're commenting on Reddit:
human
What effect (if any) does boiling water have on its pH?

My gut tells me that, because you're boiling off the water, it will concentrate whatever was in that sample of water.

Meaning if the water starts basic, it will become more basic. If the water starts acidic, it will become more acidic.

But this is just my gut and not scientific fact. Does anyone have experience with this matter?
gpt
If we are talking pure water, then the pH will go down as the temperature rises. For example the pH of pure water at 60 C is 6.54. This does not mean that the water gets more acidic, it's still neutral as the pOH also decreased to 6.54. 
The temperature dependance of the self ionization of water can be seen in this equilibrium reaction

2H2O + 59kJ <--> H3O+ + OH-

at 25C the keq for this reaction is 1E-14 which is where the 14 point scale comes from. As temperature increases you increase the concentration of the products,  H3O+ (acid) and OH- (base), both go up together, driving both the pH and the pOH down equal amounts. The neutral point is only 7 at 25C. If it was pure water it would always be neutral, regardless of temperature.