What pH is self-preserving?
I keep seeing different answers on this one, so I'm hoping to get a more definitive answer. I had assumed 10+ had the ability to self-preserve, but I see some places saying 9. That seemed low to me, but I could be wrong. One product I noticed that didn't seem to be preserved (unless I missed something!) is Dr. Bronner's unscented hemp castile soap (the baby-mild). When I tested the pH of the soap I got around 9.5. Wouldn't that be too low?