Limits for adding Citric acid in bar soap

[Garden Gives Me Joy]

I just started using 1% ppo citric acid to reduce the likelihood of soap scum and rancidity. Of course, since 10g citric acid neutralizes 6g of NaOH, I counteract this addition of citric acid with an excess of NaOH.

My impression is that many soapers use 1 to 2% citric acid for bars as a matter of course, even despite not having any foreseeable risks.

What about when multiple triggrs of rancidity exist in combination (like brine soaps, hard showering water and lack of control over storage temperatures)? Until what percentage can or should soapers add citric acid (along with the NaOH excess) without hurting soap?

 

[Mobjack Bay]

I stick to 1% and now use sodium citrate because I was getting crystals on the top of my soap when I was using more than 1% citric acid. I also use ROE (rosemary oleoresin extract) in my oils to reduce the chances of rancidity.