So I recently started looking into measuring and adjusting my final beer ph for my beers. I took a couple readings for a couple pale ales that were from a split batch and they were both very high around 5.5. I found that very odd but it was only one batch so I lowered them down to around 4.5 with lactic acid (which improved the flavor a good bit) and decided to get more data on my next brew. So a few weeks ago I brewed a black IPA and made sure to mmeasure my post boil ph which came out at 4.86. Well it's now kegged and I took a non carbonated room temp sample and it was up around 5.5 again. What I want to know is what is causing this? The only thing I can think of is a wild yeast infection, but it still doesn't make sense to me that fermentation is raising my ph rather than lowering it.