I did an impromptu mash yesterday evening with the boil early this morning. I think I finished mashing by 10pm and after a short pasteauristion I let it sit in the kettle until 7am today, when I started the boil. Temperature of the wort was down to something like 45C (110F) at that time. It's not every time I take pH readings but fairly often, just to see where I'm at. I don't take readings in the beginning or middle of the mash but usually after mash since I don't feel confident enough to adjust on the fly. Yesterday evening I forgot to take a reading so I did it this morning instead. The pH reading was almost 7....close to my water's natural pH of 7.2. The recipe calculator had an estimated pH of 5.6 and I had adjusted the mash water with some lactic acid to get in to the 5.4 area. My first thought was that my pH meter was kaput and/or needed calibration but even after calibration and testing on other fluids it kept showing 7 on my wort and pH after boil read about 6.7. So, can anyone explain to me what happend, or what might be the cause? Would leaving the wort to chill down 8 hours before boil have this effect? And most importantly, how will it affect my beer? The grist was some leftovers (but not old) from other brews, 53% pale ale, 22% wheat malt, 20% munich and a bit of crystal.